determining the motor threshold on non-braided hair during transcranial magnetic stimulation (tms)

Повышение эффективности ТМС с помощью метода плетения Sol в различных популяциях

Neuroscience research, by its very nature, involves paradigm shifts and innovations for understanding brain function, neurological disabilities, and psychiatric disorders1. Despite much progress, the discipline of neuroscience has fallen short in some aspects. For example, there exist racial disparities, both in the number of researchers, but also in the representation of subjects and patients in research. Numerous underrepresented persons from minority groups are absent from experiments and clinical studies2. Only 5 publications out of 81 peer-reviewed scalp-based EEG articles from September to October 2019 specifically indicated having a sample that included minoritized individuals. Furthermore, recent studies demonstrated that individuals from underrepresented minority groups were often misdiagnosed or failed to trust the researchers. Assari et al. found that the healthcare community, specifically half of White medical students and residents, believed that African Americans have thicker skin than Whites, which influenced their medical judgment and treatment strategies3,4. Owing to the absence of data from minority participants, research findings are less generalizable and show disparities for minority populations. To ensure that the trial population is representative of the patients who will use the medication or medicinal product and that the results are generalizable, clinical trials must include a diverse group of participants5.
Of interest to scalp-based neuroscience is the distinct shape, thickness, styling, and density that is often seen in underrepresented minority hair. The follicle shape, for example, is one feature that makes African hair distinctive. African hair comes from smaller, more elliptical, and flat follicles while Caucasian and Asian hair follicles are more circular and large6. When minorities wash their hair, it curls, causing difficulties for researchers in their experiments. Minority groups are sometimes advised to wash and straighten their hair using hair products before coming in for scalp-based imaging, but doing so can have an impact on the accuracy of the data. Data are skewed because fewer participants of minority groups would volunteer and data from them might be discarded for being a lower quality. Moreover, due to their typical hairstyles (such as cornrows and braids), minoritized individuals are sometimes perceived as being difficult to recruit and retain2. Rosen et al. studied a man of African descent who wore dreadlocks, a style worn by underrepresented minoritized individuals, and presented with disfluency in spontaneous speech7. He wanted to receive treatment using scalp-based imaging since it had emerging evidence for efficacy and was tolerable.
One of the scalp-based imaging techniques that is used widely is transcranial magnetic stimulation (TMS). TMS is a surface-based imaging technique that is used in a non-invasive way to induce localized increases in brain activity. The ability to control neuronal activity in the human brain makes TMS a crucial tool for both experimental and therapeutic neuroscience8. To set standard safety recommendations, when represented as a percentage of the motor threshold (MT), TMS intensity provides a generalizable indicator of applied stimulation that may be used with any coil shape or kind of stimulator9. The motor evoked potential (MEPs) used in determining MT can also be a measure of cortico-excitability, which is elicited by TMS over the human motor cortex10,11,12,1,3,14,15,16. TMS is delivered to the motor cortex, which causes activation in the contra-lateral regions. Typically, regions of the hand are targeted as the stimulating target is not difficult to find on the motor cortex, and attaching electrodes or visually monitoring hand/digit responses is simple. The mechanisms governing motor output can be more fully comprehended using MEPs. Since MEPs are used to measure individual differences in MT, they are now a part of practically every TMS application. In general, it is dangerous to utilize TMS without gauging some aspect of MT. If TMS is delivered above the appropriate MT, seizures may result. If TMS is delivered below MT, results may be reduced or absent (i.e., targeted neurons may not be depolarized). Accurate MT reporting is also critical in comparing studies. For example, many of the studies in our lab use a 90% value, which tells other researchers that a 110% application may result in a greater effect.
Stokes et al. examined different distances between the target region and the stimulating coil and subsequently found a direct linear relationship between the distance and the individuals&#39; MT8,17. Therefore, minority groups, some with thicker natural hair might have less accurate MTs/MEP measurements. In a survey targeting the TMS community of published authors,we found when we asked open-ended questions such as &#34;does hair play a role in impedance?&#34; experts in the field replied: &#34;It increases thresholds. Moving hair aside, compressing it, etc.;&#34; We try to use gel to bridge that contact, but not a lot that can be done;&#34; &#34; Thick hair also makes contact difficult; same as above&#34;; &#34; More hair makes stimulation more difficult-especially if it prevents good scalp contact with the coil18. Dense hair growth makes it challenging to achieve contact between the TMS coil and the scalp, leaving minimal to no contact and impeding the signal. Previous research has shown that braiding thick, coarse hair reduces impedances in scalp-based imaging6. Using the characteristics of coarse or curly hair, Etienne et al. found that braiding a participant&#39;s hair into cornrows maintains signal integrity when using EEG.
We are introducing the Sol &#34;Sun&#34; method to offer a solution to manage the hair in underrepresented minorities. Due to the thickness and coarseness of their hair, we predicted that hair that is typically seen in underrepresented minorities will respond better to this procedure since it will preserve the hair (i.e., no shaving) and allow for long-term measurement. These methods are easy to teach, learn, and perform; require no additional equipment; do not increase safety risks; honor and respect the participants&#39; natural hair; and promote pride in the participant (and researchers) who may have felt previously discouraged by scalp-based techniques.

В центре внимания автора: Повышение доступности ТМС с помощью техник плетения косичек для различных типов волос

Метод плетения косичек Sol для работы с густыми волосами во время транскраниальной магнитной стимуляции: решение проблемы потенциального смещения при стимуляции мозга

The question we are addressing is whether braiding hair can solve the age old problem in neuroscience of dealing with thick, curly, dense hair that is typical of minorities. As a leading TMS lab, we have a responsibility to promote inclusion. While our research on self-deception and self-awareness is recognized, we also strive to explore ways to increase diversity.Our survey research revealed that participants with thick hair were excluded or not efficiently tested. We offer an easy and quick method to stimulate the brain in these cases.

Определение двигательного порога на незаплетенных волосах при транскраниальной магнитной стимуляции (ТМС)

Для начала следите за температурой 70-миллиметровой катушки в форме восьмерки. Подготовьте резервные катушки и подготовьте их для немедленной замены в случае необходимости. Затем с помощью стираемого волшебного маркера отметьте область линии Cz nasian или inion, а также середину.Также измерьте и отметьте мочку уха или преаурикулярные точки. Измерьте одну треть вниз по линии правого полушария, чтобы определить оптимальное место для активации abductor pollicis brevis или APB. С помощью триггера катушки и ножного переключателя активируйте устройство TMS и отключите предохранитель от передней части машины.Расположите катушку TMS под углом 45 градусов для всех поисков и доставки TMS. Теперь, используя диск на передней панели машины, запустите стимуляцию на уровне 30% от общей производительности машины. Постепенно увеличивайте интенсивность на 2%, пока не заметите движение.Чтобы обеспечить точное размещение перед запуском определения порога двигателя, отметьте место расположения кончика катушки на шапочке для плавания. С помощью волшебного маркера обведите контуром всю переднюю часть катушки. Для визуального осмотра используйте диск, который начинается с 20% от интенсивности машины и подает около 20 импульсов.После того, как будет получено 50% ответов, запишите интенсивность в качестве двигательного порога человека. Для метода моторного потенциала прикрепите одноразовые электроды к APB и сухожилию большого пальца. С помощью заземляющего электрода вокруг тыльной стороны запястья, вместо визуального осмотра, убедитесь, что на записывающем устройстве наблюдается положительный двигательный потенциал.Определите положительную потенциальную характеристику, вызванную двигателем, как характеристику с амплитудой от размаха до пика 50 микровольт или более.

Research

JoVE Journal

Neuroscience

Determining the Motor Threshold on Non-Braided Hair During Transcranial Magnetic Stimulation (TMS)

The Sol Braiding Method for Handling Thick Hair During Transcranial Magnetic Stimulation: An Address for Potential Bias in Brain Stimulation

Transcranial Magnetic Stimulation (TMS) is a technique that is frequently utilized in neuroscience for both therapeutic and research purposes. TMS offers ...

The Sol Braiding Method for Handling Thick Hair During Transcranial Magnetic Stimulation (TMS)

Метод плетения косичек Sol для работы с густыми волосами во время транскраниальной магнитной стимуляции (ТМС)