Cognitive impairment in chronic inflammatory demyelinating polyneuropathy.

INTRODUCTION: Cognitive dysfunction has been repeatedly described as an aspect of chronic inflammatory demyelinating polyneuropathy (CIDP), but to which capacities this exactly refers and how it is embedded in the clinical phenotype of the condition remains unknown. Therefore, the detailed cognitive profiles of persons with and without CIDP were compared with each other and the disease-related results analyzed in view of main symptom complexes. METHODS: 44 persons with CIDP were studied with respect to their cognitive performances in an extensive computer-based test battery and described clinically in terms of sensorimotor disability (R-ODS), fatigue (FSMC), and mood (DESC-I). The cognitive test results were compared to those of 33 age-matched healthy controls. RESULTS: The overall cognitive performance of persons with CIDP was significantly worse than that of controls (composite score for CIDP: 33.34 ± 17.96; for Controls: 48.73 ± 18.31; U = 382, p < 0.001). Pronounced deficits prevailed in processing speed (q = 0.018), executive function (q = 0.018), memory (short-term: q = 0.020; long-term: q = 0.025) and visuoconstruction (q = 0.018). Using a hierarchical regression model, the inclusion of the factor sensorimotor disability improved the prediction of overall cognitive performance in persons with CIDP (p = 0.027). CONCLUSION: Cognitive impairment is an under-recognized aspect of CIDP, characterized by reduced processing speed, executive functioning, and memory performance. These cognitive deficits grow together with sensorimotor impairment. The findings show that CIDP goes along with functional changes beyond its classical lead symptoms.