The Cerebellar Neuropsychiatric Rating Scale

The triad of cerebellar ataxiology is the cerebellar motor, vestibular, and cerebellar cognitive affective / Schmahmann syndrome (CCAS). The CCAS affective component comprises 5 domains: Attentional control, Emotional control, Autism spectrum, Psychosis spectrum, and Social Skill Set, each with hypermetric / overshoot and hypometric / undershoot poles reflecting the dysmetria of thought and universal cerebellar transform theories. There is no validated screening instrument to assess neuropsychiatric impairments in patients with cerebellar disorders. To examine the psychometric properties of our Cerebellar Neuropsychiatric Rating Scale (CNRS) that explores these symptoms and behaviors in patients with cerebellar disorders, 21 adults with ataxia completed the CNRS and other validation measures: the Behavior Rating Inventory of Executive Function-Adult Version Informant Report, Adult Behavior Checklist, Older Adult Behavior Checklist, Neuropsychiatric Inventory Questionnaire. We examined CNRS internal consistency using Cronbach's alpha, assessed item to subscale correlations, studied ceiling and floor effects, and convergent construct validity between CNRS and validity measure subscales. Internal consistency was α > 0.70 for each of the five domains. Subscale structure was generally confirmed: 86% of correlations between CNRS and validity subscales were significant. There were no ceiling effects. Item to subscale correlations indicated adequate reliability for total scale and subdomains. NPI-Q and CNRS scores were correlated, and 86.4% (19/22) of conceptually related subscales were significant. The CNRS is a reliable and valid measure of cerebellar neuropsychiatry. Further development can refine the instrument and shed light on the patient experience of their affective dysregulation and its clinical meaningfulness.