Upper limb function is normal in patients with restless legs syndrome (Willis-Ekbom Disease)

Restless legs syndrome, now called Willis-Ekbom Disease (RLS/WED), is a sensorimotor-related sleep disorder. Little is known of the effect of RLS/WED on motor function. The current study investigated upper limb function in RLS/WED patients. We hypothesised that RLS/WED patients exhibit subtle changes in tremor amplitude but normal dexterity and movement speed and rhythmicity compared to healthy controls.

RLS/WED patients (n=17, 59 ± 7 years) with moderate disease and healthy controls (n=17, 58 ± 6 years) completed screening tests and five tasks including object manipulation, maximal pinch grip, flexion and extension of the index finger (tremor assessment), maximal finger tapping (movement speed and rhythmicity assessment), and the grooved pegboard test. Force, acceleration, and/or first dorsal interosseus EMG were recorded during four of the tasks.

Task performance did not differ between groups. Learning was evident on tasks with repeated trials and the magnitude of learning did not differ between groups.

Hand function, tremor, and task learning were unaffected in RLS/WED patients. Patients manipulated objects in a normal manner and exhibited normal movement speed, rhythmicity, and tremor.

Further research is needed to assess other types of movement in RLS/WED patients to gain insight into the motor circuitry affected and the underlying pathophysiology.