Middle and Older Adulthood in Autism: Brain and Behavioral Outcomes

Dr. Gregory Wallace dives into available research on health and quality of life outcomes associated with aging in autism. He discusses possible links between Parkinsonism and autism and details how researchers assess brain structure and function using fMRI. The speaker considers disparities in quality of life metrics and emphasizes the critical need for longitudinal studies on the lived experiences of older autistic adults. Wallace summarizes his presentation, reiterating the need for further investigation and potential barriers to research. He provides thanks and acknowledgments before the Q&A. 

Free certificates of participation are available upon successful completion of a brief knowledge quiz. If you are unable to view the quiz using the link below, see: https://bit.ly/ARI-Wallace

In this webinar: 

1:45 – Outline
2:08 – Background
5:50 – Health outcomes
7:25 – Links to Parkinsonism
9:45 – Study: Self-report on links to Parkinsonism
16:15 – Parkinsonism and quality of life
21:43 – Measuring brain structure and function
31:55 – Brain and cognitive outcomes in older autistic adults
35:13 – Quality of life (QoL) outcomes
37:05 – Subjective vs objective QoL metrics
39:13 – Study: Subjective quality of life and social support
42:45 – Summary and conclusion
44:15 – Q&A

Background

Wallace explains that our understanding of autism in older adulthood is limited because children diagnosed in the mid and late 20th century have only relatively recently begun to reach old age. The CDC estimates that around 7.28 million adults in the United States are autistic, where 1.5 million are aged 65 or older (2:08). Attaining an autism diagnosis during adulthood is difficult due to changing diagnostic criteria that rely heavily on early developmental history and compensatory skills (e.g., camouflaging). Systemic biases also keep many, especially women, from being recognized as autistic in the first place (3:30). By 2034, he continues, the U.S. is projected to have more adults over 65 than children under the age of 18, underscoring the need for further investigation into the experiences of older autistic adults (3:15). 

Parkinsonism

The speaker presents data from a study on co-occurring conditions in more than 4,000 older autistic adults (65+) compared to more than 46,000 controls (6:05). Results showed elevated rates of epilepsy, gastrointestinal (GI) conditions, hypertension, ADHD, anxiety, and suicidality (among other conditions) in autistic adults compared to controls (6:40). Older autistic adults also reported a six-fold increase in Parkinsonism – an array of motor symptoms akin to those observed in Parkinson’s Disease, including tremors, slowness in movement, and stiffness (7:25). Elevated rates of Parkinsonism have been recorded in autistic adults, though studies to date have not been able to disentangle idiopathic Parkinsonism from presentations associated with anti-psychotic medications (8:15). 

A recent investigation by Wallace and colleagues assessed links to Parkinsonism in autistic adults. Individuals who were taking anti-psychotic medications or had conditions that could impact ratings (e.g., cerebral palsy, Parkinson’s disease, stroke) were excluded from the study (9:45). Autistic participants reported more Parkinsonism than controls but less than individuals with Parkinson’s Disease. 31% of autistic participants within the cutoff range screened positive for Parkinsonism on the Parkinsonism Screening Questionnaire after (PSQ) (12:20).

Researchers then compared key outcomes for autistic patients who screened positive (PSQ+) or negative (PSQ-) for Parkinsonism. Participants responded to questionnaires about quality of life (QoL), memory function, daily living skills, and executive functioning (14:25). Wallace explains that the PSQ+ group had significantly more female-presenting individuals than the PSQ-. The PSQ+ group also reported more negative impacts on subjective QoL, memory functioning, and executive functioning, especially behavioral flexibility (16:15). PSQ groups did not differ in daily living skills, inhibitory control, or emotion regulation. These data, Wallace asserts, show how Parkinsonism significantly impacts multiple QoL factors in older autistic adults (18:55).

Brain and Cognitive Outcomes

The speaker defines gray matter as the outer layer of the brain that holds the white matter inside (21:40). Functional MRIs (fMRI) are used to measure gray matter thickness across brain regions in response to stimuli (24:30). By doing so, researchers assess functional connectivity, or which brain regions experience a spike in blood flow simultaneously (26:35). White matter, he continues, is used to measure structural connectivity. To do this, researchers observe the directional diffusion of water along fiber bundles in the brain (27:15). 

Wallace explains that older neurotypical adults experience a gradual and slowly accelerated loss of gray and white matter tissue as they age (28:25). fMRI studies on autistic older adults have published mixed results for functional and structural connectivity as well as cortical folding and hippocampal volume (29:30). Available studies on brain-based outcomes show that autistic adults experience more significant loss of white matter with age compared to controls (31:55). Investigation into cognitive aging in autism has found that executive function issues are experienced across the lifespan, particularly behavioral inflexibility (33:10). The speaker emphasizes that no longitudinal studies have been completed, meaning that none of the aforementioned findings are conclusive or well-supported. Therefore, this is a critical area for future research. 

Quality of Life Outcomes

The presenter outlines a 2012 survey study which found that 66% of autistic adults in the UK had not had their needs met since the age of 18. Participants highlighted that an overall lack of support leads to isolation, where 33% have gone weeks without speaking to anyone outside their home. Participants cited greater acceptance and accommodation as critical aspects of aging well and combating loneliness (35:25). 

Many objective QoL metrics are determined by society, which is historically not accommodating to the autistic experience. Consequently, many QoL assessments use objective things like work status and independence as metrics for success instead of subjective standards like satisfaction, fulfillment, or happiness (37:05). A Study on QoL in autistic adults found that subjective social support was significantly linked with physical, psychological, social, environmental, and autism-specific QoL indicators (39:25). Wallace notes the prevalence of co-occurring mental health issues in autism, emphasizing the critical need for addressing the overall lack of understanding and accommodation for autistic adults (38:40).

Conclusion

The speaker discusses the challenges of receiving an autism diagnosis in adulthood and how different their experiences are from individuals who were diagnosed as children. He explains how difficulties with recruitment and concerns about presenting co-occurring conditions are potential barriers to investigation (39:55). Wallace summarizes the presentation and reiterates that research into older autistic adulthood is in its infancy. However, evidence to date suggests a potential link between autism and Parkinsonism and that co-occurring medical and psychiatric conditions are common and likely detrimental to QoL. He reminds viewers that longitudinal studies are needed and reiterates the focus on subjective QoL measurements and participatory research (42:45).