Neurological Examination Findings in Autistic Adults

Friday, May 16, 2014
Atrium Ballroom (Marriott Marquis Atlanta)
B. K. Woodruff1, A. K. Duffy2, E. Pollard3, J. G. Hentz4, D. E. Locke5, Y. E. Geda6 and C. J. Smith7, (1)Neurology, Mayo Clinic Arizona, Scottsdale, AZ, (2)Clinical Studies Unit, Mayo Clinic Arizona, Scottsdale, AZ, (3)Research, SARRC, Phoenix, AZ, (4)Biostatistics, Mayo Clinic Arizona, Scottsdale, AZ, (5)Neuropsychology, Mayo Clinic Arizona, Scottsdale, AZ, (6)Psychiatry and Neurology, Mayo Clinic Arizona, Scottsdale, AZ, (7)Southwest Autism Research & Resource Center, Phoenix, AZ
Background:  Neurological signs have been described in the setting of childhood autism spectrum disorders (ASDs), including dyspraxia, abnormal movements and tone.  The presence of neurological findings in autistic adults has been described, but is not well-characterized.  

Objectives:  To describe neurological examination findings in autistic adults, with an emphasis on several findings not well-described in prior reports.  Correlations between neurological examination findings and performance on neuropsychological measures are also reported.  

Methods:  In this preliminary cross sectional study 30 autistic adults, age range 20-58 years (mean age +/- SD; 31 +/- 13 years), 73% men, with educational level (mean +/- SD) 13.4 +/- 2.1 years (range 10-18 years), underwent standard neurological examinations to identify any atypical findings.  

Results:  Neurological exam findings were divided into two categories, those traditionally associated with autism (97%), which included repetitive movements (33%), atypical gaze (50%), and atypical speech/language (57%); and other exam findings (83%) which included atypical gait (30%), tremor (30%), autonomic features (33%), and atypical hand posturing during gait assessment or with postural maintenance (40%).  Atypical hand posturing more commonly occurred in subjects with traditional repetitive movements (p=.004).  Presence of repetitive movements was inversely associated with total learning and long delay recall on the Rey Auditory Verbal Learning Test (AVLT), Delis-Kaplan (D-K) Letter Fluency and WAIS Full Scale IQ scores. Presence of atypical speech demonstrated a similar inverse association with AVLT total learning and delayed recall as well as Boston Naming Test (BNT) performance.  Atypical gaze was inversely associated with D-K Tower Test performance. Tremor was associated with better WAIS Perceptual Reasoning performance.  Abnormal gait was inversely associated with performance on multiple neuropsychological measures (several D-K tests and WAIS subscales, AVLT long delay recall, Rey Complex Figure copy and recall, BNT, Raven’s Progressive Matrices). Atypical hand posturing was inversely associated with performance on all neuropsychological measures with the exception of one D-K Number Sequencing task.  Presence of autonomic features was not associated with any pattern of neuropsychological performance.

Conclusions:  Traditional and atypical neurological exam findings are exhibited in the majority of autistic adults, with atypical speech/language and atypical gaze patterns present in approximately half and repetitive movements in approximately a third of the subjects in this sample.  Additional neurological exam findings were identified in the majority of subjects, with approximately a third or more of subjects exhibiting findings of atypical hand posturing, atypical gait, autonomic features or tremor.  Exam findings traditionally associated with autism were associated with worse performance on verbal memory, verbal fluency, naming and executive tasks.  Of the additional neurological exam findings reported, atypical gait and hand posturing were associated with worse performance on multiple neuropsychological measures.  The atypical hand posturing may represent a subtle manifestation of abnormal tone or an evolution of more traditional repetitive movements.  The non-traditional exam findings presented here offer additional opportunities to explore and potentially treat manifestations of ASDs into adulthood.