The overall goal of this EEG experiment is to clarify the interplay between conscious and non-conscious representations of emotional faces in patients with Asperger's syndrome. Several study has suggest that functional deficiency is the neuron circuitry, important for facial, emotion, recognition can partly explain social communication failure in patients with Asperger's syndrome. This EEG is primary protocol is designed to clarify deficiencies in patients with Asperger's syndrome during emotional face processing, by introducing emotional and variation tasks using photographs in the nine drawing faces.
Although this experimental approach provides insight into social communication failures in patient with Asperger's Syndrome. It can also be applied to other effective pathology, such as anxiety disorders, depression, Bernal Syndrome, and emotional violation in post traumatic stress disorders. Begin by creating an experimental program that includes an instruction screen as well as a central eye fixation screen.
Create the face stimulus screen by configuring the photograph size to be 18.3 by 24.4 centimeters with a black background color. Given that the computer screen size is 41 by 25.6 centimeters with a resolution of 1680 by 1050. Then create a scoring system for emotionality of evaluation.
Place a horizontal line ranging from negative 100 to positive 100 in a continuous scale in the center of the screen and do not include any tic marks except for the central mark. Create the program such that participants can freely evaluate the emotionality of the photograph by dragging the scoring cursor to the left for very angry, and to the right for very happy. And then complete their answer by pressing the Go"button.
Importantly, ensure that the program correctly sends time locked events according to the onset of central eye fixation, face stimulus presentation, and the pressing of the Go"button. Next, create line drawing pictures from 35 photographs by tracing the edges of each face. Use graphic software to adjust the brightness and contrast of the photograph so that the original grey scale intensity falls in either black or white.
In the effect menu, apply the sketch effect to the black and white photograph, so that only contour of the high-spacial frequency is preserved. Then click distress effect to increase the dilation of the contour lines. Finally, use the brush tool to enhance the contours and clean up any unwanted parts with the eraser tool.
Ensure that important facial features are kept in tact by checking back and forth between the original photograph and it's line drawn counterpart. In preparation for the electroencephalography or EEG recording, administer the short form of waist three to patients with Asperger's Syndrome, or AS.In order to find age and sex matched healthy controls on the verbal, performance IQ scores. On the day of recording, seat the participant in a sound isolated chamber and adjust the chair position so that the computer screen is 60 centimeters in front of the participant.
Explain the instructions of the experimental procedure and have them fill out consent forms and a questionnaire about their handedness. Next, prepare an EEG cap with 132 electrons, including 6 facial muscles channels. Connect the cap to two 64 channel amplifiers with 0.1 100 Hz analog band pass filters, to digitize raw EEGs at a 1, 000 Hz sampling rate.
Then fit the EEG cap onto the participants head. Adjust the cap so that the reference electrode is placed at the CZ position according to the EEG international 10/10 system. Gently use a blunt needle to inject conductive gel into all of the electrodes.
Use the needle to slowly stir the gel inside the electrode to ensure good conductance between the scalp and the electrode. Check the condition of the gel content at the reference and ground electrode to ensure the impedance measure is below 5 kiloms as well. Next, place one horizontal electrooculogram or HEOG electrode at the canthus of one eye, and the second at the canthus of the other eye.
Likewise, place one vertical electrooculogram or VEOG electrode above and the other below the left eye. Then place bipolar electrocardiogram electrodes on the back of the left and right hands. And bipolar electromyography electrodes between the thumb and index finger on the right hand.
Lastly, place the six facial electrodes around the eyebrow and cheek. Record any bad channels in which the impedance is higher than five kiloms by directly saving the screen showing impedance at all electrodes. Use this as a future reference for discarding bad channels during EEG data processing.
Instruct the participant to close their eyes for 12 minutes. Then record resting state EEG and double check the quality of the EEG recording. Particularly whether clear alpha waves in the occipital channels are shown in the software.
Finally, show task instructions on the screen and have the participant complete the experimental tasks. In the AS groups, the N400 component is visible in all frontal regions in the line drawing task. In controls, this same component is pronounced in the frontal, temporal, and occipital parietal regions in both the photograph and line drawing task.
Furthermore, the AS group has more comparable delta/theta synchronization to the control group in the line drawing task, but no apparent effect associated with the photograph task. Patient with Asperger's syndrome were find to have impairments in the amygdala, and its relatin based structure, which are involved in memory and retrieval of information relevant to emotions. Our protocol is the first step toward estimating the emphasis of emotionality and spectrum frequency information in patient with Asperger's syndrome compared with healthy controls.
Our analysis of EG reactions in a spacial temporal and frequency dominance allows us to differentiate the effective and cognitive functions to a degree that helps better understand the Asperger's syndrome disorder. This study contributes to the field by demonstrating a significant difference in the N400 component between the Asperger's syndrome and the control groups. Clinical application of the protocol to other adult patients with a similar type of impairment, such as Autism Spectrum disorders can be conducted with a minor modification of the face stimuli and the skull resistant.
Well designed pilot study with interview of controls and patients will validate the use of a modified version of this protocol.
