A - 122 Neuropsychological Case Study: Late-Onset Huntington’s Disease

Abstract Objective We present the neuropsychological profile of a 65-year-old male diagnosed with late-onset Huntington’s Disease (HD) in April 2024. In the context of very subtle chorea movements over the past several years, he started experiencing mood disturbances (e.g., increased irritability and social withdrawal) starting in June 2023. These changes were followed by cognitive difficulties, which led to a hospitalization for autoimmune encephalitis workup in February 2024. He described difficulties with learning and memory for future events, concentration, and executive functions (e.g., organizing and problem-solving). Method Referral from neurology to conduct a comprehensive neuropsychological evaluation to characterize his cognitive functioning. Exam, chart review, and clinical interviews were conducted. Results The cognitive profile was largely preserved, with mild attentional and executive difficulties, as well as mild challenges retrieving unstructured verbal information. This indicated subtle frontosubcortical network disruption. Self-report questionnaires indicated mild hopelessness but minimal anxiety and mood concerns. During the course of the neuropsychological evaluation, he underwent genetic testing, which was consistent with a diagnosis of HD (41 CAG repeats in the HTT gene). From a neuropsychological perspective, his psychiatric and cognitive disruption were also consistent with a diagnosis of HD. Conclusion The patient’s psychiatric and cognitive decline are now understood in light of his recent HD diagnosis. While cognitive difficulties are prevalent in individuals with HD, the low prevalence of late-onset HD makes the results of this case report particularly informative. This report contributes valuable insights into the neuropsychological presentation of older adults with HD.