Abstract BACKGROUND: Peripheral neuropathy (PN) is a non motor comorbidity in Parkinson’s disease (PD). It may worsen gait instability and disability and is frequently underdiagnosed. OBJECTIVE: To determine PN prevalence in idiopathic PD and describe its clinical, electrophysiological, and biochemical correlates in a tertiary care cohort from northeast India. METHODS: This hospital-based cross-sectional study comprised 100 consecutive patients with idiopathic PD (aged 40–80 years) fulfilling UK Parkinson’s Disease Society Brain Bank criteria. Patients underwent neurological examination, unified Parkinson’s disease rating scale part III (UPDRS-III) assessment in the ON state, Hoehn and Yahr staging, and modified Toronto clinical neuropathy assessment. Large-fiber involvement was assessed using nerve conduction studies, and small-fiber dysfunction was evaluated using bedside sensory and skin wrinkling tests. After diabetes mellitus screening, serum vitamin B12, plasma homocysteine levels, and cumulative lifetime levodopa exposure were measured. Multivariate logistic regression was performed. RESULTS: PN was identified in 46% of patients. PN-positive patients were older, had longer disease duration, higher UPDRS-III scores, and more advanced Hoehn and Yahr stages. Axonal sensorimotor neuropathy was the predominant electrophysiological pattern. Vitamin B12 deficiency (<200 pg/mL) was present in 32.6% of PN-positive patients compared with 3.7% of PN-negative patients. PN-positive patients also had higher homocysteine levels and greater cumulative levodopa exposure. Subclinical electrophysiological abnormalities were observed in a minority of PN-negative patients. On multivariate analysis, age and cumulative levodopa exposure remained independently associated with PN. CONCLUSIONS: PN is common in PD and is associated with disease severity, cumulative levodopa exposure, and metabolic abnormalities involving vitamin B12 and homocysteine. Neuropathy screening and periodic monitoring of vitamin B12 may be clinically relevant in PD management.
Kumar et al. (Mon,) studied this question.