INSAR 2026: Autism and Parkinsonism in People with Co-Occurring Intellectual Disability



About INSAR:

The International Society for Autism Research (INSAR) is the largest autism-focused society in the world. The annual conference was held in Prague, Czech Republic, on April 22 – 25, 2026. Each year, there are panel discussions, oral presentations, poster sessions, and special interest group meetings that focus on topics important to the autism research communities. Topics for the conference are submitted by researchers and community members and chosen by the INSAR committee.

INSAR 2026 Session: From Epi/Genetics to Cognitive Outcomes: Investigating the Autism-Parkinsonism Connection to Intellectual Disability

Presentation: Co-occurring Autism and Parkinsonism in a National Sample of Middle and Older Age Autistic Adults (#222.001)

Presenting Author: Gregory L. Wallace, George Washington University

Additional Authors: Claire Klein, University of North Carolina; Sha Tao, Drexel University; Lindsay Shea, Drexel University; Laura Klinger, University of North Carolina

Study Background:

Earlier research has raised the question as to whether Autistic people are more likely to be diagnosed with Parkinson’s Disease or parkinsonism (a name for conditions that include characteristics of Parkinson’s – like tremors)¹. Many of these previous studies did not account for the use on anti-psychotics, which are a common prescription for Autistic people with co-occurring intellectual disability. Some of these previous studies also had small sample sizes, which means that it is hard to say whether these findings apply to the autism community as a whole.

General Background: What is the difference between parkinsonism and Parkinson’s Disease?

Parkinsonism is an umbrella term that describes the symptoms of people with movement problems (e.g., tremors, slow, or rigid movement)². It can show up as tremors, slow movement, and stiffness. It can progress quickly and include issues like falling, dementia, or hallucinations. One potential cause of parkinsonism traits is what is commonly known as ‘drug-induced parkinsonism’, where drugs that impact dopamine levels in the brain can cause movement issues. If a person is taken off the medication, they may show improvement in their movement.

Parkinson’s Disease is under the umbrella of parkinsonism and is a degenerative brain disorder that leads to loss of motor control as well as neurological symptoms². The disease tends to progress slowly, and people can live for many years with it. Issues like depression, losing the sense of smell, gastric changes, and cognitive changes can co-occur with the movement issues. In the beginning, it can be a challenge to know if a person is just showing signs of parkinsonism, or if they have the more serious disease.

INSAR Presentation: How does parkinsonism impact Autistic people?

Researchers explored rates of parkinsonism in a large group of patients using Medicaid and Medicare healthcare claims data from the United States between 2017-2019. They divided 1.3 million patients over the age of 45 into four groups: autism-only, intellectual disability-only, autism + intellectual disability, and general population.

The researchers found that all groups had higher rates of parkinsonism compared to the general population, with the highest rates in Autistic people with co-occurring intellectual disability. Males had proportionally similar higher rates of parkinsonism diagnosis compared to females in all groups. Importantly, even when the researchers controlled for prescriptions of anti-psychotics, there were still higher rates of parkinsonism. Additionally, these higher rates of parkinsonism showed up at an earlier age for those with an autism and/or intellectual disability diagnosis compared to the general population. This means that people in the autism and/or intellectual disability communities need to be screened for parkinsonism traits at an earlier age. It also means the medical system should prepare to support these individuals as they enter movement disorder clinics for treatment. The researchers suggest that future research should investigate the shared biological pathways that involve dopamine in the brain to determine why Autistic people with co-occurring intellectual disability are the most at risk of developing parkinsonism symptoms.

What tools are there to measure movement issues related to parkinsonism?

There are a number of questionnaires that medical professionals use to assess whether someone has traits related to parkinsonism. One recently developed tool, the Parkinson’s Screening Questionnaire, was put out by the Michael J. Fox Foundation for Parkinson’s Research and was developed to help patients bring up their concerns with their doctor:

• Parkinson’s Screening Questionnaire

The most commonly used tool is the Parkinson’s Disease Questionnaire – 39 (PDQ-39). It is a self-report questionnaire that assesses health and mental health-related issues a person has experienced in the last month. While it requires a license to use, it is available for free for non-commercial, academic use.

To access a sample of the PDQ-39 questionnaire, click on the link below:

• Parkinson’s Disease Questionnaire – 39 (PDQ-39) in English
• Parkinson’s Disease Questionnaire – 39 (PDQ-39) in French

What can I do with this information?

Recognizing that you or your loved one is showing signs of motor challenges is the first step in getting an assessment and access to potential treatments. Depending on the type of parkinsonism a person has, they may respond well to new medications, medication changes, and/or movement-focused interventions to help prevent injuries. It is important to get assessed early, so be sure to contact your doctor if you have any concerns. Also, connecting with your local Parkinson’s Support Center (or in a city in your region) may be helpful for accessing information and support.

How can I learn more?

AIDE Canada and our Hub Partners have created some resources that you may find helpful:

• AIDE Canada’s Exploring Aging in Autism Webinar
• The Aging Caregiver’s Guide to Resources Toolkit – Autism Calgary
• Risk and Prevention of Falls Infographic – REENA
• AIDE Canada’s Aging Collection

Some outside organizations have created helpful materials about parkinsonism and Parkinson’s Disease:

• Parkinson Canada – Living Better with Parkinson’s
• Parkinson’s Foundation – Parkinson’s Disease vs. Parkinsonism
• Michael J. Fox Foundation for Parkinson’s Research – Resources for People Newly Diagnosed with Parkinson’s

Some suggested peer-reviewed articles about parkinsonism and autism:

• Geurts, H. M., McQuaid, G. A., Begeer, S., & Wallace, G. L. (2022). Self-reported parkinsonism features in older autistic adults: A descriptive study. Autism, 26(1), 217-229. https://doi.org/10.1177/13623613211020183
• Yin, W., Reichenberg, A., Schnaider Beeri, M., Levine, S. Z., Ludvigsson, J. F., Figee, M., & Sandin, S. (2025). Risk of Parkinson disease in individuals with autism spectrum disorder. JAMA neurology, 82(7), 687-695. doi:10.1001/jamaneurol.2025.1284
• Rast, J. E., Rosso, A. L., James, B. D., Underwood, J. F., Bergstedt, J., Ahlqvist, V. H., … & Lee, B. K. (2026). Association of neurodevelopmental conditions with Alzheimer’s disease and related dementias and Parkinson’s disease. The Journals of Gerontology, Series A: Biological Sciences and Medical Sciences, 81(4), glaf281. https://doi.org/10.1093/gerona/glaf281

References:

1. Wallace GL, Said AJ, McQuaid GA. Elevated parkinsonism symptoms in autism during middle and older adulthood are linked with psychosocial, physical health, and mental health outcomes. Autism Res. 2025 Jan;18(1):98-109. doi:10.1002/aur.3274.
2. Parkinson’s Foundation – Parkinson’s Disease vs. Parkinsonism

Photo by Alexas Fotos on Pexels