A retired man in his sixties presented in 1995 with a history of tremor, gradually worsening over the preceding eight years. He described this as a postural and action tremor affecting his upper limbs symmetrically, but there were no parkinsonian symptoms. A maternal aunt had suffered with a tremor, but no other details were known, and alcohol did not affect his tremor. More recently he thought he had become unsteady on his feet, although this only troubled him when walking in the Himalayas! He was not on any medication and was otherwise well.

On examination he was mildly dysarthric, had a postural tremor of the upper limbs with a superimposed action component, and his deep tendon reflexes were diminished. There was reduction to pain sensation in a stocking distribution. There were no other signs.

A diagnosis of either a neuropathy related tremor or essential tremor was considered, and the following tests were normal: neurophysiology, MR brain, cerebrospinal fluid, EEG, and routine blood tests, including the known SCA mutations, and immunoglobulins.

His tremor did not to respond to propranolol, isoniazid, or valproate and four years later both his tremor and unsteadiness had deteriorated. Reassessment revealed absent reflexes, his tremor remained postural and on action, with the frequency and amplitude of essential tremor. There was probably superimposed dysmetria and he had mild gait ataxia, but no other new signs. Repeat nerve conduction studies were again normal. A diagnosis of “atypical essential tremor” …