Tremor

INDEX

Origin

Thought to arise secondary to central processing of mistimed and distorted peripheral input that occurs with neuropathic disease. Neuropathic tremor occurs in association with peripheral neuropathies. The commonest neuropathies associated with tremors are immune-mediated demyelinating, such as CIDP and MMN, and hereditary peripheral neuropathies (HMSN). The relationship to proprioceptive loss is variable.  Tremor is also described with plasmocytoma and amyloidosis.

Classification

Tremor is particularly frequent in paediatric manifestations of HSMN and the combination of a hereditary neuropathy with postural tremor has historically been called ‘Roussy–Levy syndrome’.

 

Clinical Features

Often there are additional neurological symptoms present in these patients, mainly muscle weakness and sensory deficits.  Characteristically, these patients present with action tremor, with postural tremor and kinetic tremor, but rest tremor also occurs.  The tremor predominantly affects more distal muscles, often irregular with variable amplitude.

The relationship to proprioceptive loss is variable.

Age of onset

Typically in elderly

Diagnosis

Based on history, diagnostic tests, and nerve conduction studies.

Differential Diagnosis:

Diagnostic Tests:

IgM neuropathy: Gradient of tremor frequency on EMG e.g. Biceps 3 Hz FDI 5 Hz

IgM paraproteinemia 80%

Anti MAG antibodies

Autoantibodies against nodal and paranodal proteins such as neurofascin. Two isoforms have been detected: neurofascin 155 (NF155) is located in the paranodal loops of myelinating Schwann cells. Patients positive for NF155 antibodies constitute a specific subgroup with a severe phenotype, poor response to treatment and disabling tremor.

 

Treatment

Beta-blockers and other drugs used in ET have been reported to be helpful for neuropathic tremor, and success with VIM DBS has also been reported