Intention Tremor - Diagnosis

Diagnosis

A working diagnosis is made from a neurological examination and evaluation. Parts of a complete examination include a physical examination, MRI, patient history, and electrophysiological and accelerometric studies. A diagnosis of solely intention tremor can only be made if the tremor is of low frequency (below 5 Hz) and without the presence of any resting tremors. Electrophysiological studies can be useful in determining frequency of the tremor, and accelerometric studies quantify tremor amplitude. MRI is used to locate damage to and degradation of the cerebellum that may be causing the intention tremor. Focal lesions such as neoplasms, tumors, hemorrhages, demyelination, or other damage may be causing dysfunction of the cerebellum and correspondingly the intention tremor.

Physical tests are an easy way to determine the severity of the intention tremor and impairment of physical activity. Common tests that are used to assess intention tremor are the finger-to-nose and heel-to-shin tests. In a finger-to-nose test, a physician has the individual touch their nose with their finger while monitoring for irregularity in timing and control of the movement. An individual with intention tremors will have coarse side-to-side movements that increase in severity as the finger approaches the nose. Similarly, the heel-to-shin test evaluates intention tremors of the lower extremities. In such a test, the individual places their heel on the top of their opposite knee and is then instructed to slide their heel down their shin to their ankle while being monitored for coarse and irregular side-to-side movement as the heel approaches the ankle. Important historical elements to the diagnosis of intention tremor are:

1. age at onset
2. mode of onset (sudden or gradual)
3. anatomical affected sites
4. rate of progression
5. exacerbating and remitting factors
6. alcohol abuse
7. family history of tremor
8. current medications

Secondary symptoms commonly observed are dysarthria (a speech disorder characterized by poor articulation and slurred speech), nystagmus (rapid involuntary eye movement, especially rolling of the eyes), gait problems (abnormality in walking), and postural tremor or titubation (to-and-fro movements of the neck and trunk). A postural tremor may also accompany intention tremors.