Posttraumatic paroxysmal nocturnal hemidystonia

Movement disorders secondary to craniocerebral trauma

Over the past few decades it has been recognized that traumatic brain injury may result in various movement disorders. In survivors of severe head injury, post-traumatic movement disorders were reported in about 20%, and they persisted in about 10% of patients. The most frequent persisting movement disorder in this population is kinetic cerebellar outflow tremor in about 9%, followed by dystonia in about 4%. While tremor is associated most frequently with cerebellar or mesencephalic lesions, patients with dystonia frequently have basal ganglia or thalamic lesions. Moderate or mild traumatic brain injury only rarely causes persistent post-traumatic movement disorders. It appears that the frequency of post-traumatic movement disorders overall has been declining which most likely is secondary to improved treatment of brain injury. In patients with disabling post-traumatic movement disorders which are refractory to medical treatment, stereotactic neurosurgery can provide long-lasting benefit. While in the past the primary option for severe kinetic tremor was thalamotomy and for dystonia thalamotomy or pallidotomy, today deep brain stimulation has become the preferred treatment. Parkinsonism is a rare consequence of single head injury, but repeated head injury such as seen in boxing can result in chronic encephalopathy with parkinsonian features. While there is still controversy whether or not head injury is a risk factor for the development of Parkinson's disease, recent studies indicate that genetic susceptibility might be relevant.

Oral pharmacotherapy of childhood movement disorders

Movement disorders, a common problem in children with neurologic impairment, are receiving increasing clinical attention. The differences in movement disorders between adults and children are striking; presentation is frequently insidious and may be characterized by mild hypotonia. The clinical manifestations of extrapyramidal disorders are profoundly influenced by the age of onset. The conditions reviewed in this article are expressed clinically by the occurrence of abnormalities of movement and posture, often in association with disturbances of muscle tone. This article reviews empiric drug use and recommendations for childhood movement disorders.

Paroxysmal kinesigenic dyskinesias

The paroxysmal dyskinesias (PxDs) are involuntary, intermittent movement disorders manifested by dystonia, chorea, athetosis, ballismus or any combination of these hyperkinetic disorders. Paroxysmal kinesigenic dyskinesia (PKD), one of the four main types of PxD, involves sudden attacks of dyskinesias induced by voluntary movements. PKD most commonly occurs sporadically or as an autosomal-dominant familial trait with variable penetrance. Many causes of secondary PKD are being recognized. The exact pathophysiology of the PxDs awaits further elucidation, although basal ganglia dysfunction appears to play a major role. Although the precise gene remains unknown, genetic linkage studies have isolated loci on chromosome 16, which colocalizes with the locus for familial infantile convulsions and paroxysmal choreoathetosis in some studies. The episodic nature of PKD and its relationship with other episodic diseases, such as epilepsy, migraine, and episodic ataxia, suggests channelopathy as a possible underlying etiology. PKD may remit spontaneously, but it also responds well to anticonvulsants as well as some other agents.

Secondary paroxysmal dyskinesias

Paroxysmal dyskinesias (PxDs) are involuntary, episodic movements that include paroxysmal kinesigenic (PKD), paroxysmal nonkinesigenic (PNKD), and paroxysmal hypnogenic (PHD) varieties. Although most PxDs are primary (idiopathic or genetic), we found 17 of our 76 patients with PxD (22%) to have an identifiable cause for their PxD (10 men; mean age, 41.4 years). Causes included peripheral trauma (in three patients), vascular lesions (in four), central trauma (in four), kernicterus (in two), multiple sclerosis (in one), cytomegalovirus encephalitis (in one), meningovascular syphilis (in one), and migraine (in one). The latency from insult to symptom onset ranged from days (trauma) to 18 years (kernicterus), with a mean of 3 years. Nine patients had PNKD, two had PKD, five had mixed PKD/PNKD, and one had PHD. Hemidystonia was the most common expression of the paroxysmal movement disorder, present in 11 patients. Both of the patients with PKD had symptom durations of <5 minutes. Symptom duration ranged from 10 seconds to 15 days for PNKD and from 5 minutes to 45 minutes for mixed PKD/PNKD. There were no uniformly effective therapies, but anticonvulsant drugs, clonazepam, and botulinum toxin injections were the most beneficial. Awareness of the variable phenomenology and the spectrum of causes associated with secondary PxD will allow for more timely diagnosis and early intervention.

Head injury and posttraumatic movement disorders

WE REVIEW THE phenomenology, pathophysiology, pathological anatomy, and therapy of posttraumatic movement disorders with special emphasis on neurosurgical treatment options. We also explore possible links between craniocerebral trauma and parkinsonism. The cause-effect relationship between head injury and subsequent movement disorder is not fully appreciated. This may be related partially to the delayed appearance of the movement disorder. Movement disorders after severe head injury have been reported in 13 to 66% of patients. Although movement disorders after mild or moderate head injury are frequently transient and, in general, do not result in additional disability, kinetic tremors and dystonia may be a source of marked disability in survivors of severe head injury. Functional stereotactic surgery provides long-term symptomatic and functional benefits in the majority of patients. Thalamic radiofrequency lesioning, although beneficial in some patients, frequently is associated with side effects such as increased dysarthria or gait disturbance, particularly in patients with kinetic tremor secondary to diffuse axonal injury. Deep brain stimulation is used increasingly as an option in such patients. It remains unclear whether pallidal or thalamic targets are more beneficial for treatment of posttraumatic dystonia. Trauma to the central nervous system is an important causative factor in a variety of movement disorders. The mediation of the effects of trauma and the pathophysiology of the development of posttraumatic movement disorders require further study. Functional stereotactic surgery should be considered in patients with disabling movement disorders refractory to medical treatment.