We thank Angus Begg (The Bionics Institute) for his assistance in the video protocol. We acknowledge Dr. Sue Finch (Statistical Consulting Centre and Melbourne Statistical Consulting Platform, University of Melbourne) who provided statistical support. This work was supported by the funding through the National Health and Medical Research Council (1066565), the Victorian Lions Foundation, and The Victorian Government&#39;s Operational Infrastructure Support Program.

All methods described were reviewed and approved by the local human research ethics committee at Melbourne Health. Informed consent was obtained from the participant prior to the study.
1. Equipment setup
<ol>
	<li>Prepare the electromagnetic motion tracker with 3 miniature motion sensors as per the manufacturer&#39;s guidelines. Prior to data collection, ensure each sensor is sampled at a minimum 250 Hz, displacement is measured in millimeter units and rotations (pitch, roll, and yaw) are in degrees. Ensure that all internal filterings are disabled, and the position of the sensors set to reference a static origin (usually the electromagnetic transmitter).</li>
	<li>Affix a load cell (minimum tension range 100 N, S-type recommended) to the patient harness at shoulder-level using a rope with a minimum diameter of 10 mm. 
	NOTE: The harness system and rope are suitable for use in participants weighing up to 120 kg.</li>
	<li>Connect the load cell to data acquisition unit (A/D Converter).</li>
	<li>Connect the trigger output from the data acquisition unit into a trigger input of the motion tracker to ensure synchronized recording. Set data acquisition unit sampling rate to match the motion tracker and disable all filtering.</li>
	<li>Conduct the experiment in a quiet room to minimize distractions during the assessment. Allow enough space for participants to take several corrective steps to regain balance. 
	NOTE: Patients with Parkinson&#39;s disease and retropulsion are known to take 5-6 steps backward during the pull test.</li>
	<li>Place falls mat on the floor as a precautionary measure.</li>
	<li>Clean the harness, sensors, and wires with a hospital grade disinfectant wipe before testing each participant. 
	NOTE: Video recording (e.g., using a portable camera on a tripod) of the instrumented pull test procedure is recommended so that any irregularities during data processing can be referenced against the video data of a trial.</li>
</ol>
2. Participant selection and preparation
<ol>
	<li>Identify appropriate participants for study: participants can comprise a range of ages, disease conditions and severity where postural responses are of interest and balance assessment typically employs the clinical pull test. Ensure that participants can stand independently and generate a corrective balance response not requiring assistance to recover (i.e., up to Grade 1 postural instability according to the UPDRS).</li>
	<li>Exclude any persons with cardiovascular, vestibular, vision and musculoskeletal conditions (including persons requiring foot orthotics or splints), that may impair balance performance unless this is the subject of the investigation, those on contact precautions, and those on medication known to affect balance or attention (e.g., antidepressants, neuroleptics, benzodiazepines, antiepileptics, antiarrhythmics, and diuretics).</li>
	<li>Have the participant wear comfortable loose clothing on the day of the experiment and remove shoes prior to the pull test procedure.</li>
	<li>Assist the participant in putting on the customized trunk harness with the load cell. Click the buckles around the chest and waist. Ensure adjustment straps on the harness are tight but comfortable. Do not allow more than 50 mm of slack in the harness when pulling on the rope. In participants with known postural instability, ensure that an assistant is present when the harness is applied while the participant is standing.</li>
	<li>Attach motion sensors using medical tape to the sternal notch (at the level of the second and third thoracic vertebra), and on the feet at the right and left ankle malleolus. 
	NOTE: Apply the sensors on participants with known postural instability in sitting. All cables must be routed carefully to avoid trip hazards.</li>
	<li>Ask the participant to stand bare feet, in a comfortable stance (according to the participant&#39;s preferred base of support) along vertical and horizontal line markings on the floor. Note the participant&#39;s feet position. Ask the participant to also note their own feet position in order to revert to the same position after every pull. Monitor the participant&#39;s feet placement after every trial and ask the participant to return to the original feet position if any deviations are observed.</li>
	<li>Instruct the participant to focus on artwork 1.5 m ahead at the eye level with hands by their side to minimize distractions between pulls.</li>
</ol>
3. Instrumented pull test procedure
<ol>
	<li>Perform the instrumented pull test in accordance with the clinical pull test guidelines described by the UPDRS5.</li>
	<li>Explain the test procedure, and let the participant know that stepping is allowed to regain balance following the backward pull. Discourage anticipatory responses such as forward trunk flexion, stiffening in posture or knee flexion prior to the pull. Note these responses if they occur during the experiment.</li>
	<li>Prior to each pull, ensure the participant is attentive by asking the participant to focus on a picture hanging on the wall. Ensure the participant is standing upright, with eyes open, hands by their side, and their feet placed on the designated markers in a comfortable stance.</li>
	<li>Stand behind the participant. Apply a brisk pull of sufficient force to generate a trunk and step response via the rope and load cell held perpendicular to the shoulder level of the participant.</li>
	<li>After each pull ensure the participant returns to the original feet positioning. Reset the position back to designated markers on the floor and repeat 35 times. 
	NOTE: The number of trials can be varied according to the experimental design and clinical population.</li>
	<li>Allow participants a short rest of 2 min after every 10 trials or as required to reduce the effects of fatigue and ensure attention is focused on the task. Participants can choose to sit or stand. Request that participants refrain from talking in between pulls unless requesting a break or expressing discomfort during the procedure.</li>
	<li>As an additional safety precaution, ensure that the assessor and assistant are standing with their backs close to a wall while allowing enough room for the participant to take several steps backward. 
	NOTE: The assessor must always be prepared to catch the patient. An assistant is required for safety when participants with known postural instability are assessed.</li>
	<li>Detach sensors and assist the participant out of the harness following completion of the instrumented pull test procedure.</li>
</ol>
4. Signal processing
NOTE: Use a suitable data science platform such as MATLAB, R, or Python. Commands shown here are for MATLAB and example code is available as Supplementary File.
<ol>
	<li>Import data recorded during step 3.4 into a suitable data science platform: csvread().</li>
	<li>Align the motion tracker and load cell data using trigger signals and resample to a higher sampling rate: 1 kHz resample() function if required.</li>
	<li>High-pass filter all motion tracking and load cell data with a 0.05 Hz cut-off frequency to remove base-line drift: butter() and filtfilt().</li>
	<li>Double differentiate the trunk motion tracking displacement data to obtain trunk velocity and acceleration: diff().</li>
	<li>Using either the trigger signal or a peak-detection algorithm applied to the load cell data, slice recordings to obtain epochs of each individual pull test trial: findpeaks() function.</li>
	<li>Detect and reject trials with the anticipatory truncal movement. A forward trunk displacement immediately prior to the pull administration usually presents as a peak at least three standard deviations above the baseline mean of the trunk sensor: std() and mean().</li>
	<li>Determine postural reaction time as the difference between the onset of trunk displacement (3 standard deviations above baseline mean) following the pull and the turning point of the trunk velocity curve (indicating the beginning of trunk deceleration): differentiate, diff(), and use zero crossing detector, zcd().</li>
	<li>Determine the magnitude of the postural response as the peak deceleration of the trunk: min() or max().</li>
	<li>Calculate the step reaction time as the difference between the onset of truncal displacement (as per 4.7) to the initial movement of the stepping limb: 3 standard deviations above the baseline mean.</li>
	<li>Determine the step response magnitude by calculating the total displacement of the foot in millimeters (mm), from initial foot lift-off to contact of the stepping limb arresting backward retropulsion. Exclude steps less than 50 mm, as the change in the base of support is considered negligible24: min() or max().</li>
	<li>Calculate the peak pull force and rate of force development from the load cell: max() for pull; max() and diff() for rate of force. 
	NOTE: The peak pull force indicates the instantaneous maximum force delivered, whereas the force rate is the slope of the force versus time curve indicating how rapidly the force was generated.</li>
</ol>

<ol>
	<li>Shemmell, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Interactions+between+stretch+and+startle+reflexes+produce+task-appropriate+rapid+postural+reactions.">Interactions between stretch and startle reflexes produce task-appropriate rapid postural reactions.</a> Frontiers in Integrative Neuroscience. 9, (2015).</li><li>Kerr, G. K., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Predictors+of+future+falls+in+Parkinson+disease.">Predictors of future falls in Parkinson disease.</a> Neurology. 75 (2), 116-124 (2010).</li><li>Latt, M. D., Lord, S. R., Morris, J. G. L., Fung, V. S. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Clinical+and+physiological+assessments+for+elucidating+falls+risk+in+Parkinson's+disease.">Clinical and physiological assessments for elucidating falls risk in Parkinson's disease.</a> Movement disorders: official journal of the Movement Disorder Society. 24 (9), 1280-1289 (2009).</li><li>Foreman, K. B., Addison, O., Kim, H. S., Dibble, L. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Testing+balance+and+fall+risk+in+persons+with+Parkinson+disease,+an+argument+for+ecologically+valid+testing.">Testing balance and fall risk in persons with Parkinson disease, an argument for ecologically valid testing.</a> Parkinsonism &amp; Related Disorders. 17 (3), 166-171 (2011).</li><li>Fahn, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Recent Developments in Parkinson's Disease. , 153-163 (1987).</li><li>Hunt, A. L., Sethi, K. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+pull+test:+a+history.">The pull test: a history.</a> Movement disorders: official journal of the Movement Disorder Society. 21 (7), 894-899 (2006).</li><li>Visser, M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Clinical+tests+for+the+evaluation+of+postural+instability+in+patients+with+parkinson's+disease.">Clinical tests for the evaluation of postural instability in patients with parkinson's disease.</a> Archives of Physical Medicine and Rehabilitation. 84 (11), 1669-1674 (2003).</li><li>Jacobs, J. V., Horak, F. B., Van Tran, K., Nutt, J. G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=An+alternative+clinical+postural+stability+test+for+patients+with+Parkinson's+disease.">An alternative clinical postural stability test for patients with Parkinson's disease.</a> Journal of Neurology. 253 (11), 1404-1413 (2006).</li><li>Nonnekes, J., Goselink, R., Weerdesteyn, V., Bloem, B. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+retropulsion+test:+a+good+evaluation+of+postural+instability+in+Parkinson's+disease?.">The retropulsion test: a good evaluation of postural instability in Parkinson's disease?.</a> Journal of Parkinson's Disease. 5 (1), 43-47 (2015).</li><li>Bloem, B. R., Beckley, D. J., van Hilten, B. J., Roos, R. A. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Clinimetrics+of+postural+instability+in+Parkinson's+disease.">Clinimetrics of postural instability in Parkinson's disease.</a> Journal of Neurology. 245 (10), 669-673 (1998).</li><li>Thevathasan, W., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Pedunculopontine+nucleus+deep+brain+stimulation+in+Parkinson's+disease:+A+clinical+review.">Pedunculopontine nucleus deep brain stimulation in Parkinson's disease: A clinical review.</a> Movement Disorders. 33 (1), 10-20 (2018).</li><li>Visser, J. E., Carpenter, M. G., van der Kooij, H., Bloem, B. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+clinical+utility+of+posturography.">The clinical utility of posturography.</a> Clinical Neurophysiology. 119 (11), 2424-2436 (2008).</li><li>McVey, M. A., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Early+biomechanical+markers+of+postural+instability+in+Parkinson's+disease.">Early biomechanical markers of postural instability in Parkinson's disease.</a> Gait and Posture. 30 (4), 538-542 (2009).</li><li>Mancini, M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Trunk+accelerometry+reveals+postural+instability+in+untreated+Parkinson's+disease.">Trunk accelerometry reveals postural instability in untreated Parkinson's disease.</a> Parkinsonism &amp; Related Disorders. 17 (7), 557-562 (2011).</li><li>Nonnekes, J., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Are+postural+responses+to+backward+and+forward+perturbations+processed+by+different+neural+circuits?.">Are postural responses to backward and forward perturbations processed by different neural circuits?.</a> Neuroscience. 245, 109-120 (2013).</li><li>Horak, F. B., Dimitrova, D., Nutt, J. G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Direction-specific+postural+instability+in+subjects+with+Parkinson's+disease.">Direction-specific postural instability in subjects with Parkinson's disease.</a> Experimental Neurology. 193 (2), 504-521 (2005).</li><li>Colebatch, J. G., Govender, S., Dennis, D. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Postural+responses+to+anterior+and+posterior+perturbations+applied+to+the+upper+trunk+of+standing+human+subjects.">Postural responses to anterior and posterior perturbations applied to the upper trunk of standing human subjects.</a> Experimental Brain Research. 234, 367-376 (2016).</li><li>Graus, S., Govender, S., Colebatch, J. G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+postural+reflex+evoked+by+brief+axial+accelerations.">A postural reflex evoked by brief axial accelerations.</a> Experimental Brain Research. 228 (1), 73-85 (2013).</li><li>Govender, S., Dennis, D. L., Colebatch, J. G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Axially+evoked+postural+reflexes:+influence+of+task.">Axially evoked postural reflexes: influence of task.</a> Experimental Brain Research. 233, 215-228 (2015).</li><li>Smith, B. A., Carlson-Kuhta, P., Horak, F. B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Consistency+in+Administration+and+Response+for+the+Backward+Push+and+Release+Test:+A+Clinical+Assessment+of+Postural+Responses:+Consistency+of+Push+and+Release+Test.">Consistency in Administration and Response for the Backward Push and Release Test: A Clinical Assessment of Postural Responses: Consistency of Push and Release Test.</a> Physiotherapy Research International. 21 (1), 36-46 (2016).</li><li>Di Giulio, I., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Maintaining+balance+against+force+perturbations:+impaired+mechanisms+unresponsive+to+levodopa+in+Parkinson's+disease.">Maintaining balance against force perturbations: impaired mechanisms unresponsive to levodopa in Parkinson's disease.</a> Journal of Neurophysiology. , (2016).</li><li>Nonnekes, J., de Kam, D., Geurts, A. C. H., Weerdesteyn, V., Bloem, B. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Unraveling+the+mechanisms+underlying+postural+instability+in+Parkinson's+disease+using+dynamic+posturography.">Unraveling the mechanisms underlying postural instability in Parkinson's disease using dynamic posturography.</a> Expert Review of Neurotherapeutics. 13 (12), 1303-1308 (2013).</li><li>Tan, J. L., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Neurophysiological+analysis+of+the+clinical+pull+test.">Neurophysiological analysis of the clinical pull test.</a> Journal of Neurophysiology. , (2018).</li><li>McVey, M. A., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+effect+of+moderate+Parkinson's+disease+on+compensatory+backwards+stepping.">The effect of moderate Parkinson's disease on compensatory backwards stepping.</a> Gait and Posture. 38 (4), 800-805 (2013).</li><li>Valls-Sole, J., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Reaction+time+and+acoustic+startle+in+normal+human+subjects.">Reaction time and acoustic startle in normal human subjects.</a> Neuroscience Letters. 195 (2), 97-100 (1995).</li><li>Carlsen, A. N., Maslovat, D., Lam, M. Y., Chua, R., Franks, I. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Considerations+for+the+use+of+a+startling+acoustic+stimulus+in+studies+of+motor+preparation+in+humans.">Considerations for the use of a startling acoustic stimulus in studies of motor preparation in humans.</a> Neuroscience and Biobehavioral Reviews. 35 (3), 366-376 (2011).</li><li>Nanhoe-Mahabier, W., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=First+trial+reactions+and+habituation+rates+over+successive+balance+perturbations+in+Parkinson's+disease.">First trial reactions and habituation rates over successive balance perturbations in Parkinson's disease.</a> Neuroscience. 217, 123-129 (2012).</li><li>Aminian, K., Najafi, B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Capturing+human+motion+using+body-fixed+sensors:+outdoor+measurement+and+clinical+applications.">Capturing human motion using body-fixed sensors: outdoor measurement and clinical applications.</a> Computer animation and virtual worlds. 15 (2), 79-94 (2004).</li><li>De Luca, C. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+use+of+surface+electromyography+in+biomechanics.">The use of surface electromyography in biomechanics.</a> Journal of Applied Biomechanics. 13 (2), 135-163 (1997).</li><li>Horak, F. B., Nashner, L. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Central+programming+of+postural+movements:+adaptation+to+altered+support-surface+configurations.">Central programming of postural movements: adaptation to altered support-surface configurations.</a> Journal of Neurophysiology. 55 (6), 1369-1381 (1986).</li><li>Saito, H., Yamanaka, M., Kasahara, S., Fukushima, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Relationship+between+improvements+in+motor+performance+and+changes+in+anticipatory+postural+adjustments+during+whole-body+reaching+training.">Relationship between improvements in motor performance and changes in anticipatory postural adjustments during whole-body reaching training.</a> Human Movement Science. 37, 69-86 (2014).</li><li>Kam, D. D., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Dopaminergic+medication+does+not+improve+stepping+responses+following+backward+and+forward+balance+perturbations+in+patients+with+Parkinson's+disease.">Dopaminergic medication does not improve stepping responses following backward and forward balance perturbations in patients with Parkinson's disease.</a> Journal of Neurology. 261 (12), 2330-2337 (2014).</li><li>Peterson, D. S., Horak, F. B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+Effect+of+Levodopa+on+Improvements+in+Protective+Stepping+in+People+With+Parkinson's+Disease.">The Effect of Levodopa on Improvements in Protective Stepping in People With Parkinson's Disease.</a> Neurorehabilitation and Neural Repair. 30 (10), 931-940 (2016).</li><li>Haubenberger, D., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Transducer-based+evaluation+of+tremor.">Transducer-based evaluation of tremor.</a> Movement Disorders. 31 (9), 1327-1336 (2016).</li><li>Elble, R., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Task+force+report:+scales+for+screening+and+evaluating+tremor:+critique+and+recommendations.">Task force report: scales for screening and evaluating tremor: critique and recommendations.</a> Movement disorders: official journal of the Movement Disorder Society. 28 (13), 1793-1800 (2013).</li><li>Adkin, A. L., Carpenter, M. G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=New+insights+on+emotional+contributions+to+human+postural+control.">New insights on emotional contributions to human postural control.</a> Frontiers in Neurology. 9, 789 (2018).</li><li>Huffman, J. L., Horslen, B., Carpenter, M., Adkin, A. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Does+increased+postural+threat+lead+to+more+conscious+control+of+posture?.">Does increased postural threat lead to more conscious control of posture?.</a> Gait and Posture. 30 (4), 528-532 (2009).</li><li>Valls-Sole, J., Rothwell, J. C., Goulart, F., Cossu, G., Munoz, E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Patterned+ballistic+movements+triggered+by+a+startle+in+healthy+humans.">Patterned ballistic movements triggered by a startle in healthy humans.</a> The Journal of Physiology. 516 (Pt 3), 931-938 (1999).</li><li>Campbell, A. D., Squair, J. W., Chua, R., Inglis, J. T., Carpenter, M. G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=First+trial+and+StartReact+effects+induced+by+balance+perturbations+to+upright+stance.">First trial and StartReact effects induced by balance perturbations to upright stance.</a> Journal of Neurophysiology. 110 (9), 2236-2245 (2013).</li><li>Oude Nijhuis, L. B., Allum, J. H. J., Valls-Sol&#233;, J., Overeem, S., Bloem, B. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=First+trial+postural+reactions+to+unexpected+balance+disturbances:+a+comparison+with+the+acoustic+startle+reaction.">First trial postural reactions to unexpected balance disturbances: a comparison with the acoustic startle reaction.</a> Journal of Neurophysiology. 104 (5), 2704-2712 (2010).</li></ol>

No conflicts of interest, financial or otherwise, are declared by the authors.

Here, we have demonstrated the protocol for instrumentation of the clinical pull test, taking a method widely used in clinical practice and yielding an objective measurement of postural responses in addition to the important aspect of the pull administration. Using semi-portable motion tracking, this method offers a means of measurement that is more accessible compared to conventional laboratory techniques28. Using this method, researchers can explore characteristics of postural responses to a top...

An erratum was issued for: <a href="https://www.jove.com/video/59309/an-instrumented-pull-test-to-characterize-postural-responses">An Instrumented Pull Test to Characterize Postural Responses</a>.&#160; Author&#160;affiliations were&#160;updated.
The affiliations for Joy Tan were updated from:
1. Department of Medical Bionics, The University of Melbourne&#160; 
2. Department of Neurology, The Royal Melbourne Hospital
to:
1.&#160;Department of Medical Bionics, The University of Melbourne&#160; 
2.&#160;Department of Neurology, The Royal Melbourne Hospital 
4. The Bionics Institute
The affiliations for Thushara&#160;Perera&#160;were updated from:
1. Department of Medical Bionics, The University of Melbourne&#160; 
3. Department of Neurology, Austin Hospital
to:
1.&#160;Department of Medical Bionics, The University of Melbourne&#160; 
4. The Bionics Institute

An erratum was issued for: <a href="https://www.jove.com/video/59309/an-instrumented-pull-test-to-characterize-postural-responses">An Instrumented Pull Test to Characterize Postural Responses</a>.&#160; The affiliation section&#160;was updated.

Erratum: An Instrumented Pull Test to Characterize Postural Responses

Postural reflexes act to maintain&#160;balance and upright stance in response to perturbations1. Impairment of these postural responses in disorders such as Parkinson&#39;s disease results in postural instability, and commonly leads to falls, reduced walking confidence and diminished quality of life2,3,4. In clinical practice, postural reflexes are typically assessed with the pull test, where an examiner briskly pulls the patient backward at the shoulders and visually grades the response5,6,7,8. Postural instability is usually scored using the Unified Parkinson&#39;s Disease Rating Scale (UPDRS) (0 - normal to 4 - severe), as published by the International Movement Disorder Society5. This method has been used extensively in the assessment of individuals with Parkinson&#39;s disease but suffers poor reliability and very limited scaling (score/4)6,7,9. Pull test scores often do not correlate with important clinical endpoints such as falls and the integer-based rating lacks sensitivity to detect fine postural changes10,11.
Laboratory-based objective measures offer precise information about the nature of balance response by quantifying kinetic (e.g., the center of pressure), kinematic (e.g., joint goniometry/limb displacement) and neurophysiological (e.g., muscle recruitment) endpoints12. These methods may identify abnormalities before postural instability is clinically evident and track changes over time, including responses to treatment13,14.
Tools for Quantifying Postural Instability
Conventional techniques of dynamic posturography commonly employ moving platforms. Resulting postural responses are quantified using a combination of posturography, electromyography (EMG), and accelerometry12,15,16. However, the bottom-up responses of platform perturbations - which evoke a response like slipping on a wet floor, are fundamentally different from the top-down postural responses of the clinical pull test - as may occur when being bumped in a crowd. Emerging evidence suggests truncal perturbations yield different postural characteristics to those of moving platforms17,18,19. Accordingly, others have attempted truncal perturbations in the laboratory using complex techniques including motors, pulleys, and pendulums15,20,21,22. Methods of measurement are often expensive and inaccessible and comprise of video-based motion capture that requires dedicated space in specialized laboratories20,21. Ideally, an objective method to characterize pull test responses should have excellent psychometric properties, be easy to administer, simple to operate, widely accessible, and portable. This is important to facilitate widespread adoption of the technique as an alternative assessment tool to assess postural responses within research and potentially, clinical settings.
The Instrumented Pull Test 
The aim of this protocol is to offer researchers a technique for objective assessment of postural responses to the pull test. A semi-portable and widely available electromagnetic motion capture system underpins the technique. The perturbation involves manual pulls that do not require specialized mechanical systems. This method has sufficient sensitivity to detect small differences in postural reaction times and response amplitudes; therefore, it is suited to capturing potential abnormalities rated from normal up to grade 1 postural instability according to the UPDRS (postural instability with unassisted balance recovery)5. This method may also be utilized to explore the effects of therapy on postural instability. The protocol described here is derived from that in Tan et al.23.

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			<td height="21" style="height:21px;">MATLAB Software</td>
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			<td height="21" style="height:21px;">S&#38;F Technical Harness and Belt</td>
			<td>Lowepro</td>
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an instrumented pull test to characterize postural responses

Impairment of postural reflexes, termed postural instability, is a common and disabling deficit in Parkinson's disease. To assess postural reflexes, clinicians typically employ the pull test to grade corrective responses to a backward perturbation at the shoulders. However, the pull test is prone to issues with reliability and scaling (score/4). Here, we present an instrumented version of the pull test to more precisely quantify postural responses. Akin to the clinical test, pulls are manually administered except pull force is also recorded. Displacements of the trunk and feet are captured by a semi-portable motion tracking system. Raw data represent distance traveled (in millimeter units), making subsequent interpretation and analysis intuitive. The instrumented pull test also detects variabilities influencing pull test administration, such as pull force, thereby identifying and quantifying potential confounds that can be accounted for by statistical techniques. The instrumented pull test could have application in studies seeking to capture early abnormalities in postural responses, track postural instability over time, and detect responses to therapy.

The instrumented pull test (Figure 1) was used to investigate trunk and step responses in a young, healthy cohort23. Thirty-five trials were presented serially, with an auditory stimulus delivered concurrently with each pull (Figure 2). The auditory stimulus was either 90 dB (normal) or 116 dB (loud). The loud stimulus has been demonstrated as sufficient to trigger StartReact effects, where pre-prepared re...

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An Instrumented Pull Test to Characterize Postural Responses

Impairment of postural reflexes, termed postural instability, is difficult to quantify. Clinical assessments such as the pull test suffer issues with reliability and scaling. Here, we present an instrumented version of the pull test to objectively characterize postural responses.

Impairment of postural reflexes, termed postural instability, is a common and disabling deficit in Parkinson's disease. To assess postural reflexes, ...

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10.7K Views.  The University of Melbourne. Impairment of postural reflexes, termed postural instability, is difficult to quantify. Clinical assessments such as the pull test suffer issues with reliability and scaling. Here, we present an instrumented version of the pull test to objectively characterize postural responses. 

Video: An Instrumented Pull Test to Characterize Postural Responses

An Alternative to the Traditional Cold Pressor Test: The Cold Pressor Arm Wrap

Recently research on the relationship between stress and cognition, emotion, and behavior has greatly increased. These advances have yielded insights into important questions ranging from the nature of stress&#39; influence on addiction1 to the role of stress in neural changes associated with alterations in decision-making2,3. As topics being examined by the field evolve, however, so too must the methodologies involved. In this article a practical and effective alternative to a classic stress induction technique, the cold pressor test (CPT), is presented: the cold pressor arm wrap (CPAW). CPT typically involves immersion of a participant&#39;s dominant hand in ice-cold water for a period of time4. The technique is associated with robust activation of the sympatho-adrenomedullary (SAM) axis (and release of catecholamines; e.g.&#160;adrenaline and noradrenaline) and mild-to-moderate activation of the hypothalamic-pituitary-adrenal (HPA) axis with associated glucocorticoid (e.g.&#160;cortisol) release. While CPT has been used in a wide range of studies, it can be impractical to apply in some research environments. For example use of water during, rather than prior to, magnetic resonance imaging (MRI) has the potential to damage sensitive and expensive equipment or interfere with acquisition of MRI signal. The CPAW is a practical and effective alternative to the traditional CPT. Composed of a versatile list of inexpensive and easily acquired components, CPAW makes use of MRI-safe gelpacs cooled to a temperature similar to CPT rather than actual water. Importantly CPAW is associated with levels of SAM and HPA activation comparable to CPT, and can easily be applied in a variety of research contexts. While it is important to maintain specific safety protocols when using the technique, these are easy to implement if planned for. Creation and use of the CPAW will be discussed.

The cold pressor test is a classic stress induction task used in a wide range of research examining the relationship between stress and cognition, emotion, and behavior. In this article, a practical and versatile alternative to the traditional cold pressor test is presented: the cold pressor arm wrap.

Recently research on the relationship between stress and cognition, emotion, and behavior has greatly increased. These advances have yielded insights into ...

Assessing Forelimb Function after Unilateral Cervical SCI using Novel Tasks: Limb Step-alternation, Postural Instability and Pasta Handling

Cervical spinal cord injury (cSCI) can cause devastating neurological deficits, including impairment or loss of upper limb and hand function. A majority of the spinal cord injuries in humans occur at the cervical levels. Therefore, developing cervical injury models and developing relevant and sensitive behavioral tests is of great importance. Here we describe the use of a newly developed forelimb step-alternation test after cervical spinal cord injury in rats. In addition, we describe two behavioral tests that have not been used after spinal cord injury: a postural instability test (PIT), and a pasta-handling test. All three behavioral tests are highly sensitive to injury and are easy to use. Therefore, we feel that these behavioral tests can be instrumental in investigating therapeutic strategies after cSCI.

Three new behavioral tests (forelimb step-alternation, postural instability test, pasta handling test) for evaluating forelimb function after cervical spinal cord injury in rodents are described.

Cervical spinal cord injury (cSCI) can cause devastating neurological deficits, including impairment or loss of upper limb and hand function. A majority ...

Methods to Test Visual Attention Online

Online data collection methods have particular appeal to behavioral scientists because they offer the promise of much larger and much more representative data samples than can typically be collected on college campuses. However, before such methods can be widely adopted, a number of technological challenges must be overcome &#8211; in particular in experiments where tight control over stimulus properties is necessary. Here we present methods for collecting performance data on two tests of visual attention. Both tests require control over the visual angle of the stimuli (which in turn requires knowledge of the viewing distance, monitor size, screen resolution, etc.) and the timing of the stimuli (as the tests involve either briefly flashed stimuli or stimuli that move at specific rates). Data collected on these tests from over 1,700 online participants were consistent with data collected in laboratory-based versions of the exact same tests. These results suggest that with proper care, timing/stimulus size dependent tasks can be deployed in web-based settings.

To replicate laboratory settings, online data collection methods for visual tasks require tight control over stimulus presentation. We outline methods for the use of a web application to collect performance data on two tests of visual attention.

Online data collection methods have particular appeal to behavioral scientists because they offer the promise of much larger and much more representative ...

How to Study Placebo Responses in Motion Sickness with a Rotation Chair Paradigm in Healthy Participants

Placebo responses occur in every medical intervention when patients or participants expect to receive an effective treatment to relieve symptoms. However, underlying mechanisms of placebo responses are not fully understood. It has repeatedly been shown that placebo responses are associated with changes in neural activity but for many conditions it is unclear whether they also affect the target organ, such as the stomach in motion sickness. Therefore, we present a methodology for the multivariate assessment of placebo responses by subjective, behavioral and objective measures in motion sickness with a rotation chair paradigm. The physiological correlate of motion sickness is a shift in gastric myoelectrical activity towards tachygastria that can be recorded with electrogastrography. The presented study applied the so-called balanced placebo design (BPD) to investigate the effects of ginger compared to placebo and the effects of expectations by verbal information. However, the study revealed no significant main or interactional effects of ginger (as a drug) or information on outcome measures but showed interactions when sex of participants and experimenters are taken into considerations. We discuss limitations of the presented study and report modifications that were used in subsequent studies demonstrating placebo responses when rotation speed was lowered. In general, future placebo studies have to identify the appropriate target organ for the studied placebo responses and to apply the specific methods to assess the physiological correlates.

An experimental rotation chair paradigm is used to investigate whether a placebo intervention on motion sickness affects subjective outcome measures only or also affects behavioral and objective measures in a balanced placebo design.

Placebo responses occur in every medical intervention when patients or participants expect to receive an effective treatment to relieve symptoms. However, ...

Assessing the Multiple Dimensions of Engagement to Characterize Learning: A Neurophysiological Perspective

In a recent theoretical synthesis on the concept of engagement, Fredricks, Blumenfeld and Paris1 defined engagement by its multiple dimensions: behavioral, emotional and cognitive. They observed that individual types of engagement had not been studied in conjunction, and little information was available about interactions or synergy between the dimensions; consequently, more studies would contribute to creating finely tuned teaching interventions. Benefiting from the recent technological advances in neurosciences, this paper presents a recently developed methodology to gather and synchronize data on multidimensional engagement during learning tasks. The technique involves the collection of (a) electroencephalography, (b) electrodermal, (c) eye-tracking, and (d) facial emotion recognition data on four different computers. This led to synchronization issues for data collected from multiple sources. Post synchronization in specialized integration software gives researchers a better understanding of the dynamics between the multiple dimensions of engagement. For curriculum developers, these data could provide informed guidelines for achieving better instruction/learning efficiency. This technique also opens up possibilities in the field of brain-computer interactions, where adaptive learning or assessment environments could be developed.

This paper aims to describe the techniques involved in the collection and synchronization of the multiple dimensions (behavioral, affective and cognitive) of learners&#8217; engagement during a task.

In a recent theoretical synthesis on the concept of engagement, Fredricks, Blumenfeld and Paris1 defined engagement by its multiple dimensions: ...

Sit-to-stand-and-walk from 120% Knee Height: A Novel Approach to Assess Dynamic Postural Control Independent of Lead-limb

Individuals with sensorimotor pathology e.g., stroke have difficulty executing the common task of rising from sitting and initiating gait (sit-to-walk: STW). Thus, in clinical rehabilitation separation of sit-to-stand and gait initiation - termed sit-to-stand-and-walk (STSW) - is usual. However, a standardized STSW protocol with a clearly defined analytical approach suitable for pathological assessment has yet to be defined.
Hence, a goal-orientated protocol is defined that is suitable for healthy and compromised individuals by requiring the rising phase to be initiated from 120% knee height with a wide base of support independent of lead limb. Optical capture of three-dimensional (3D) segmental movement trajectories, and force platforms to yield two-dimensional (2D) center-of-pressure (COP) trajectories permit tracking of the horizontal distance between COP and whole-body-center-of-mass (BCOM), the decrease of which increases positional stability but is proposed to represent poor dynamic postural control.
BCOM-COP distance is expressed with and without normalization to subjects&#39; leg length. Whilst COP-BCOM distances vary through STSW, normalized data at the key movement events of seat-off and initial toe-off (TO1) during steps 1 and 2 have low intra and inter subject variability in 5 repeated trials performed by 10 young healthy individuals. Thus, comparing COP-BCOM distance at key events during performance of an STSW paradigm between patients with upper motor neuron injury, or other compromised patient groups, and normative data in young healthy individuals is a novel methodology for evaluation of dynamic postural stability.

Here, we present a novel protocol to measure positional stability at key events during the sit-to-stand-to-walk using the center-of-pressure to the whole-body-center-of-mass distance. This was derived from the force platform and three-dimensional motion-capture technology. The paradigm is reliable and can be utilized for the assessment of neurologically compromised individuals.

Individuals with sensorimotor pathology e.g., stroke have difficulty executing the common task of rising from sitting and initiating gait (sit-to-walk: ...

The Other End of the Leash: An Experimental Test to Analyze How Owners Interact with Their Pet Dogs

It has been suggested that the way in which owners interact with their dogs can largely vary and influence the dog-owner bond, but very few objective studies, so far, have addressed how the owner interacts with the dog. The goal of the present study was to record dog owners&#39; interaction styles by means of objective observation and coding. The experiment included eight standardized situations in which owners of pet dogs were asked to perform specific tasks including both positive (i.e. playing, teaching a new task, showing a preference towards an object in a food searching task, greeting after separation) and potentially distressing tasks (i.e. physical restriction during DNA sampling, putting a T-shirt onto the dog, giving basic obedience commands while the dog was distracted). The video recordings were coded off-line using a specifically designed coding scheme including scores for communication, social support, warmth, enthusiasm, and play style, as well as frequency of behaviors like petting, praising, commands, and attention sounds. Exploratory Factor Analysis of the 20 variables measured revealed 3 factors, labeled as Owner Warmth, Owner Social Support, and Owner Control, which can be viewed as analogues to parenting style dimensions. The experimental procedure introduced here represents the first standardized measure of interaction styles of dog owners. The methodology presented here is a useful tool to investigate individual variation in the interaction style of pet dog owners that can be used to explain differences in the dog-human relationship, dogs&#39; behavioral outcomes, and dogs stress coping strategies, all crucial elements both from a theoretical and applied point of view.

This article presents eight different experimental tasks, mirroring the everyday life of dogs and owners, used to analyze how owners interact with their dogs in a standardized way. The tasks included both positive (e.g. play) and negative (potentially stressful) situations (e.g. physical restriction).

It has been suggested that the way in which owners interact with their dogs can largely vary and influence the dog-owner bond, but very few objective ...

Testing for Metacognitive Responding Using an Odor-based Delayed Match-to-Sample Test in Rats

Metamemory involves the cognitive ability to assess the strength of one&#39;s memories. To explore the possibility of metamemory in non-human animals, numerous behavioral tasks have been created, many of which utilize an option to decline memory tests. To assess metamemory in rats, we utilized this decline-test option paradigm by adapting previous visual delayed-match-to-sample tests (DMTS)1,2 developed for primate species to an odor-based test suitable for rodents. First,&#160;rats are given a sample to remember by digging in a cup of scented sand. After a delay, the rat is presented with four distinctly scented cups, one of which contains the identical scent experienced during the sample; if this matching cup is selected, then the rat obtains a preferred, larger reward. Selection of any of the other three non-matching sand-filled scented cups results in no reward. Retention intervals are individually titrated such that subjects perform between 40 and 70% correct, therefore ensuring rats sometimes remember and sometimes forget the sample. Here, the operational definition of metamemory is the ability to distinguish between the presence and absence of memory through behavioral responding. Towards this end, on two-thirds of trials, a decline option is presented in addition to the four choice cups (choice trials). If the decline-test option- an unscented colored sand cup, is selected, the subject receives a smaller less-preferred reward and avoids the memory test. On the remaining third of trials, the decline-test option is not available (forced trials), causing subjects to guess the correct cup when the sample is forgotten. On choice tests, subjects that know when they remember should select the decline option when memory is weak rather than take the test and choose incorrectly. Therefore, significantly higher performance on chosen tests as compared to forced memory tests is indicative of the adaptive use of the decline-test response and metacognitive responding.

This protocol describes a method for investigating the possibility of metamemory, or memory awareness, in rodents. The odor-based delayed-matching-to-sample paradigm is a novel, ecologically-relevant behavioral test useful for determining the extent to which rodents can adaptively respond based on cognitively monitoring the strength of their memory states.

Metamemory involves the cognitive ability to assess the strength of one&#39;s memories. To explore the possibility of metamemory in non-human animals, ...

Continuous Theta Burst Stimulation of the Posterior Medial Frontal Cortex to Experimentally Reduce Ideological Threat Responses

Decades of behavioral science research have documented functional shifts in attitudes and ideological adherence in response to various challenges, but little work to date has illuminated the neural mechanisms underlying these dynamics. This paper describes how continuous theta burst transcranial magnetic stimulation may be employed to experimentally assess the causal contribution of cortical regions to threat-related ideological shifts. In the example protocol provided here, participants are exposed to a threat prime-an explicit reminder of their own inevitable death and bodily decomposition-following a downregulation of the posterior medial frontal cortex (pMFC) or a sham stimulation. Next, disguised within a series of distracter tasks, participants' relative degree of ideological adherence is assessed-in the present example, with regard to coalitional prejudice and religious belief. Participants for whom the pMFC has been downregulated exhibit less coalitionally biased responses to an immigrant critical of the participants' national in-group, and less conviction in positive afterlife beliefs (i.e., God, angels, and heaven), despite having recently been reminded of death. These results complement prior findings that continuous theta burst stimulation of the pMFC influences social conformity and sharing and illustrate the feasibility of investigating the neural basis of high-level social cognitive shifts using transcranial magnetic stimulation.

Threats reliably evoke shifts in high-level ideological investment, but little work to date has explored the neural mechanisms underlying these dynamics. This paper describes how continuous theta burst transcranial magnetic stimulation may be employed to test the contribution of the posterior medial frontal cortex (and/or other regions) to threat-related ideological shifts.

Decades of behavioral science research have documented functional shifts in attitudes and ideological adherence in response to various challenges, but ...

Multi-Modal Signals for Analyzing Pain Responses to Thermal and Electrical Stimuli

The assessment of pain relies mostly on methods that require a person to communicate. However, for people with cognitive and verbal impairments, existing methods are not sufficient as they lack reliability and validity. To approach this problem, recent research focuses on an objective pain assessment facilitated by parameters of responses derived from physiology, and video and audio signals. To develop reliable automated pain recognition systems, efforts have been made in creating multimodal databases in order to analyze pain and detect valid pain patterns. While the results are promising, they only focus on discriminating pain or pain intensities versus no pain. In order to advance this, research should also consider the quality and duration of pain as they provide additional valuable information for more advanced pain management. To complement existing databases and the analysis of pain regarding quality and length, this paper proposes a psychophysiological experiment to elicit, measure, and collect valid pain reactions. Participants are subjected to painful stimuli that differ in intensity (low, medium, and high), duration (5 s / 1 min), and modality (heat / electric pain) while audio, video (e.g., facial expressions, body gestures, facial skin temperature), and physiological signals (e.g., electrocardiogram [ECG], skin conductance level [SCL], facial electromyography [EMG], and EMG of M. trapezius) are being recorded. The study consists of a calibration phase to determine a subject&#8217;s individual pain range (from low to intolerable pain) and a stimulation phase in which pain stimuli, depending on the calibrated range, are applied. The obtained data may allow refining, improving, and evaluating automated recognition systems in terms of an objective pain assessment. For further development of such systems and to investigate pain reactions in more detail, additional pain modalities such as pressure, chemical, or cold pain should be included in future studies. Recorded data of this study will be released as the &#8220;X-ITE Pain Database&#8221;.

This article focuses on the experimental elicitation of pain through heat (thermal) and electrical stimulation while recording physiological, visual, and paralinguistic responses. It aims at collecting valid multimodal data for analyzing pain based on its intensity, quality, and duration.&#160;

The assessment of pain relies mostly on methods that require a person to communicate. However, for people with cognitive and verbal impairments, existing ...