Curriculum · Neurology
Classification of tremor
What it is
Tremor is told apart by when it appears.
- Resting tremor occurs when a person is relaxed.
- Intention tremor occurs when a person makes a direct and purposeful body movement.
- Postural tremor occurs when holding a position against gravity, such as holding the arms outstretched.
- An action tremor, that is a kinetic or intention tremor, occurs during movement of the affected body part from one point to another.
Resting tremors and intention tremors occur at two distinctly different times, which is why the timing is the first question.
How it presents
Essential tremor is a kinetic tremor. The amplitude of the kinetic tremor is more than that of the postural tremor in essential tremor, and in advanced essential tremor there can be a resting tremor, more restricted to the arms. It is not limited to the arm: it can be seen in the neck in about 20% of patients. Enhanced physiological tremor is a difficult differential, but it can be excluded because no neck tremor is associated with it. Parkinson disease carries the resting tremor, low in amplitude and low in frequency, together with cogwheel rigidity, slower and smaller finger movements, a mask face, a soft voice, and a gait with stooped posture, decreased arm swing, small steps and difficulty doing a turn. Its cardinal symptoms are bradykinesia, rigidity, resting tremor and postural instability. Symptoms are usually of unilateral onset, progressive, with persistent asymmetry and symptoms worse on the side of onset, a clear and definite response to levodopa, and a clinical course of 10 years or more. Other associated symptoms are affective disorder such as depression, autonomic dysfunction, constipation, REM sleep behavior disorder, impaired olfaction and taste, and fatigue. Cerebellar disease brings the intention tremor, inside the DASHING signs: dysdiadochokinesis; ataxia with falls to the side of the lesion; slurred staccato or scanning speech; hypotonia and reduced power; intention tremor; nystagmus; and broad-based gait issues. Cerebellar insults are always ipsilateral. Intention tremor also sits in the Charcot triad of multiple sclerosis, held by the mnemonic SIN: scanning speech, intention tremor, nystagmus.