The correlation between motor and cognitive dysfunction in multiple sclerosis

Abstract

The correlation between motor and cognitive dysfunction in multiple sclerosis Konstantin K. Mineev, Andrey M. Petrov, Marina V. Votintseva, Igor' D. Stolyarov N.P. Beсhtereva Institute of Human Brain of the Russian Academy of Sciences, St. Petersburg, Russia Introduction. Impaired ambulation is one of the most common and disabling symptoms in multiple sclerosis (MS). Cognitive impairment occurs in the early stages of MS and worsens as the disease progresses. The aim of the study was to investigate the correlation between walking speed and distance and the severity of neurological and cognitive impairment in MS. Materials and methods. We examined 59 patients with relapsing-remitting MS in clinical remission. Motor function was evaluated using the timed 25-foot walk (mobility and leg function performance test based on a timed 25-walk), the nine-hole peg test was used to assess upper limb motor function, the Ashworth Scale was used to evaluate lower limb spasticity, the EDSS scale (pyramidal function) was used to evaluate gait spasticity, and tests for sustained attention, counting skills, short-term and delayed memory, mathematical logic, speech fluency, and sensorimotor reaction speed were used to assess cognitive function. Results. In MS, an increased score on the disability scale was accompanied by increased motor disturbances, reduced distance covered when walking, decreased walking speed, and slower hand movements. Increased spasticity was accompanied by a deterioration in cognitive test performance. The study showed a high correlation between spasticity and reduced computational abilities, mathematical logic, and the ability to remember shapes. Walking distance correlated with attention span and short-term and delayed memory while walking speed characteristics correlated with the movement speed of the non-dominant hand. Slower hand activity correlated with the conducted cognitive tests, with the most significant differences recorded in the non-dominant hand. Conclusion. The study results indicate significant and varied motor and cognitive dysfunction in MS patients, caused by damage to both the conduction pathways in the brain and spinal cord and the cortical grey matter. The obtained data on the close correlation between motor and cognitive impairments allow us to better understand the mechanisms of MS development and to apply this knowledge in clinical practice.