For the past several years, parents of children with autism and adults with autism have described unusual pain responses in individuals with autism. Because people with autism don’t communicate the same way as those without autism, they may not be able to express their response to physical pain. Or, it may be possible that sensory issues may somehow change pain processing, or alter the ability to process a stimulus as painful or not painful.
Very little research has been done to address this critical issue affecting those with ASD and impacting their clinical care plans. One reason why is that studying pain would require knowingly exposing people with and without autism to painful stimuli.
Beginning this summer, ASF will be funding a new study by Dr. Michelle Failla and Dr. Carissa Cascio at Vanderbilt University that we believe will enable us to begin to understand pain response in people with autism. This study will examine both verbal responses to pain, as well as nonverbal responses like heart rate, facial expression and stress response, to a mild stimuli in adults with ASD.
Alison Singer is hooked up to the heart rate and galvanic skin response monitors
The findings will help clinicians understand pain sensitivity so that new strategies to assess and manage pain can be developed.
The study protocol was approved by the IRB of Vanderbilt University and exceeded all safety requirements. Nonetheless, before we felt comfortable recommending that adults with autism enroll in the study, ASF Chief Science Officer Dr. Alycia Halladay and I traveled to Nashville to experience the pain stimuli personally. We both felt strongly that we couldn’t ask individuals to subject themselves to pain unless we had experienced it ourselves and could offer a first-person account.
Three “tasks” were involved in the study. Each measured our pain sensitivity using heat. In the first task, a small hot plate (approximately 1 inch by 1 and ½ inches) was placed on our calf and we were asked to push a button when we felt pain. The heat ramped up gradually and as soon as we pushed the button the heat went off and the pain was gone. In the second task, the thermal stimulator was again placed on our calf and we were asked to rate the amount of pain we felt on a scale of 0 to 100 (0 indicating no pain and 100 indicating the worst pain).
A small hotpad is placed on the calf
Three short “tasks” were involved in the study. Each measured our pain sensitivity to heat delivered by a small thermode (a hot plate, approximately 1 inch by 1 and ½ inches) placed on our calf. During the tasks, we felt heat for a short period and then were asked to rate the amount of pain we felt on a scale of 0 to 100 (0 indicating no pain and 100 indicating the worst pain). The highest amount of pain we felt in any task was 60-70 but most were lower and several were 0. In the third task, the small hot plate was administered for bursts of 15 seconds and again we were asked to rate the amount of pain we felt on a scale of 0-100. Here our highest rating was a 20. Throughout the procedure we were repeatedly reminded that we could stop at any time by saying “stop”. During the trials, investigators also monitor pulse rate, galvanic skin response and facial expression as nonverbal
Michelle Failla, the PI, makes sure the levels of heat are safe
indicators of pain. Another part of this study that we did not participate in involves exposing participants to the same pain protocols while they are in the FMRI machine. This phase is important because it will enable researchers to measure how the brain responds to different phases of pain, including the seconds leading up to the pain, the response, and endurance of pain.
The first phase of this work will focus on adults with autism. Participants are required to have an IQ above 80 and to personally consent to participation. In addition, participants must successfully complete a quiz to show that they fully understand the consent process and their rights as participants, including the right to change their mind and withdraw consent at any time. In addition, two adults with autism will serve as consultants to the scientists conducting the study; one is a member of the faculty at the Vanderbilt School of Music and the other is a Vanderbilt MD-PhD student.
Alison Singer and Alycia Halladay unscathed after experiencing the study.
Based on our first-hand experience, we both feel very comfortable encouraging adults with and without autism to participate in this important study, as long as they are capable of consenting. Participants will feel some pain, but it is short and not difficult to experience. In fact, I experienced more heat-based pain on the plane ride home when my laptop overheated on my legs. All of the members of this research team are actively engaged and very focused on making sure participants do not experience any more discomfort than is necessary. If the pain response were not altered in people with autism, then this sort of research would not be necessary. But in order to make sure that individuals with autism are not unnecessarily feeling pain that could otherwise be treated, this type of project is needed.
For more information about this study, visit the Cascio Lab website.
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