The head and neck manifestations of movement disorders are wide ranging. They are classified into akinetic rigid disorders or hyperkinetic movement disorders. Parkinson’s disease represents the most common akinetic entity. First described in 1817 by James Parkinson, there are three cardinal signs that can lead to the diagnosis of Parkinson’s disease: bradykinesia, tremor at rest, and cogwheel rigidity. These signs can be accompanied by a diminished blink rate and soft monotone voice without tremor. A crucial finding in Parkinson’s disease is that tremor virtually never involves the head. Although Parkinson’s disease usually is idiopathic, approximately 25% of patients have parkinsonian syndrome of other causes, most commonly supranuclear palsy. These patients generally have earlier, more intense dysarthria and dysphagia and early falls, disordered eye movements, dementia, and depression.

Many of the otolaryngologic manifestations of neurologic disease appear as hyperkinetic movement disorders. Movements are involuntary and characterized by an excessive degree of muscular activity. Tremor is characterized by rhythmic oscillation of a body part and may be differentiated from all other movement disorders, which are not rhythmic. The classification of tremor is clinically based: Parkinson’s disease is characterized by resting tremor; essential tremor is maximal with activity. The two most common tremors manifested in the head and neck are Parkinson’s disease and essential tremor. Patients with Parkinson’s disease often have involvement of the chin, lip, and tongue. Jaw and tongue tremor is less common in essential tremor, which characteristically involves the head, lips, and upper extremity. Essential tremor may cause a vocal quaver because of laryngeal involvement.

Chorea manifests itself as brief, nonsustained movements that are not rhythmic or stereotypical. They may be combined with athetosis, which is characterized by slow, writhing movements. At the extreme is ballismus, which is violent, flinging motion. Otolaryngologists commonly see orofacial or buccolingual-masticatory
chorea. The most common is tardive dyskinesia. Tardive dyskinesia is well known to be associated with the use of traditional neuroleptic drugs. However, use of metoclopramide (a common antiemetic) occasionally is associated with tardive dyskinesia because it has the same antidopaminergic effects as haloperidol.

Dystonia is a syndrome of sustained muscular activity that frequently causes repetitive twisting movements or abnormal posture. Dystonia is classified as primary or secondary. Adult patients most commonly experience primary dystonia, which is best classified according to topographic features. Focal dystonia has a predilection for the head and neck region and may be unifocal or multifocal. Blepharospasm (involuntary eye closure) is the most common dystonia of the head and neck region. Oromandibular dystonia may involve the tongue, jaw, or pharyngeal musculature. Meige’s disease involves a combination of blepharospasm and oromandibular dystonia. The second most common dystonia manifested in the head and neck is cervical dystonia or torticollis. Control of dystonia is achieved by means of injection of botulinum toxin. Most cases of dystonia are poorly controlled with oral medications.

Tics represent erratic and abrupt muscular activities on a background of motor silence. They usually are stereotypical and manifest themselves diversely (e.g., with repetitive sniffing or throat clearing). A common finding among children is transient tic of childhood. These tics may arise and be seen as a mannerism and most of the time disappear without intervention. It is important to remember that tics may be drug induced or a manifestation of a recent illness.

Palatal tremor (formerly known as palatal myoclonus) is characterized by rhythmic contraction (at 1 to 2 Hz) of the soft palate. Palatal tremor may be classified as either essential or secondary. Essential palatal tremor is characterized by lack of an underlying lesion, and unlike the situation with secondary palatal tremor there is no spread to adjacent musculature. Secondary palatal tremor involves the levator veli palatini muscles and is the result of a diverse group of lesions that interrupt the central tegmental tracts in the brainstem. Neuroimaging studies such as MRI are therefore appropriate in the care of patients with palatal tremor. Secondary palatal tremor may be asymptomatic until it spreads to the orbital muscles, causing oscillopsia, or to the tongue.

Hemifacial spasm is manifested by involuntary paroxysmal movements of the muscles innervated by the facial nerve. Spasms are almost always unilateral and follow recovery or partial recovery from Bell’s palsy. A number of other conditions may be responsible for this finding, so it is important to obtain an MRI study. Intracranial lesions include aberrant vascular loops close to the facial nerve, epidermoid cyst, and meningioma. Botulinum toxin has been shown to be effective in controlling the spasms, and vascular decompression is curative in the case of an aberrant vascular loop.