Tremor in neuropathies of different origin

Background and purpose: Tremor accompanies some polyneuropathies, but its prevalence and its clinical and electro-physiological manifestations are not well known. The aim of the study was to assess the occurrence and characteristics of hand tremor in patients with polyneuropathy of different origins, as well as relations between the occurrence of tremors and clinical and neurographic findings of polyneuropathy. Material and methods: Eighty-nine patients diagnosed with polyneuropathy of known aetiology, and 50 age- and sex-matched healthy volunteers were included in the study All subjects were interviewed regarding the occurrence of tremor. Tremor was assessed clinically and objectively using a tri-axial accelerometer and electromyographic (EMG) recordings. A load test with a weight of 500 g was performed in order to differentiate between enhanced physiological tremor (EPT) and essential tremor-like (ET-L) tremor. Results: Tremor was found in 59.5% of patients in clinical assessment and in 74% of patients in objective evaluation, significantly more often than in controls (12%). Tremor was detected in all types of polyneuropathy apart from paraproteinaemic IgM polyneuropathy. Tremor was postural (70%), but resting (51%) or kinetic (32%) tremor was also present. In the majority of cases, the severity of the tremor was mild. Essential tremor-like tremor prevailed in the study group. The occurrence of hand tremor was not related to the axonal or demyelinating type of polyneuropathy, nor to the conduction velocity or other electrophysiolog-ical findings of the investigated upper limb nerves. Conclusion: Tremor accompanies 60-70% of patients with polyneuropathy; it is mostly postural, ET-L type with mild severity, and unrelated to other typical clinical and electrophysiological findings of neuropathy.