Objective:

To determine the prevalence of mild and major neurocognitive disorder in premanifest HD patients using DSM-5 criteria.

Background:

Huntington’s disease (HD) is a neurological disorder characterized by progressive dysfunction across three domains: movement, cognition, and behavior. The diagnosis of manifest HD is based primarily on motor dysfunction, however cognitive decline typically begins in the pre-manifest (preHD) phase and often exerts an understated functional impact. The Diagnostic and Statistical Manual of Mental Disorders (DSM-5) has established criteria for both mild and major neurocognitive disorder (NCD), however, these are not routinely applied in HD.  

Design/Methods:

The following cognitive battery was administered to both preHD (CAG repeat > 36) and control participants: Stroop Color and Word Test (SCWT), Symbol Digit Modalities Test (SDMT), and Verbal fluency (Category). DSM-5 criteria for NCD were then applied to these test results to determine diagnostic prevalence of NCD.

Results:

23 preHD participants and 26 Healthy Controls (HC) were enrolled. PreHD participants' age was (40.7±11.5) (mean±SD), years of education (15.7±2.7), CAG repeat length (42.1±2.7). The UHDRSTM total motor score was (2.0±2.2). HC age was (37.1 ± 12.0), and education of (16.6 ± 2.1). Group differences in age and education were not statistically significant, however, group differences were observed for Verbal Fluency (p = 0.03) and Word Reading (p = 0.004). Using DSM-5 criteria, the prevalence of NCD-mild was 35% in preHD vs. 3% in HC, NCD-major was 13% in preHD versus 0% in HC.

Conclusions:

The prevalence of NCD in preHD is surprisingly elevated. Establishing a clinical diagnosis of NCD prior to motor manifestation can be critical for access to services, anticipating longitudinal care, expanding recruitment for disease-modifying trials, and validating patient concerns when appropriate. Consideration should be given to incorporating NCD criteria into clinical practice.