Evaluation of Cognitive Disorders in Huntington’s Disease and Their Relationship with Motor Symptoms and Trinucleotide Repeat Expansion

Abstract

Objectives: Huntington’s disease (HD), characterized by choreiform movements, psychiatric problems, and dementia, is an inherited progressive neurodegenerative disorder. While HD is typically perceived as a motor disorder, cognitive decline could manifest before the clinical symptoms. Cognitive impairments might appear as emotional instability, decreased vocabulary, or impaired executive functions. Herein, we aimed to evaluate the cognitive findings of our patients diagnosed with HD and the relationship with disease parameters. Methods: Our study included 15 patients and fifteen controls. To determine the clinical findings of the patients, the unified HD rating scale (UHDRS) was administered, and total motor score (TMS), independence scale scores, and functional capacity scores were calculated. To assess the cognitive status of individuals, the Montreal Cognitive Assessment Battery Turkish validated form (MOCA-TR), Stroop test Turkish validated form (Stroop test TBAG form), and Symbol Digit Modalities Test were conducted. Results: The MoCA-TR scores were significantly reduced in HD patients compared to controls (p<0.001). Among all patients, there was a notable elongation in completion time for the Stroop test TBAG form than controls (p<0.05). The MoCA-TR showed a robust negative correlation with the TMS while exhibiting a marked positive correlation with the independence scale score and functional capacity. Conversely, the MoCA-TR demonstrated a moderate negative correlation with the disease burden score (DBS) and a pronounced negative relationship with the progression rate (p<0.05). A strong opposing correlation was observed between cytosine-adenine-guanine (CAG) repeats and the age of disease onset, whereas a highly significant positive relationship emerged between CAG repeats and the DBS (p<0.05). Conclusion: We have demonstrated a strong correlation between patients’ cognitive scores and disease clinical findings. Patients’ cognitive scores have also been shown to impact disease burden and disease progression rate. The designation of cognitive impairment in the early stages could contribute to personalized disease-modifying treatment strategies