The dystonias.

Both the pharmacological and pathological data suggest that the dystonias may be a group of disorders with multiple etiologies. Knowledge in this field would be immeasurably advanced if a genetic linkage or a consistent regional or chemical brain pathology could be identified for any single subtype. Both kinds of advance are required before the specific etiology can be identified. The problem in trying to identify disturbances in a disease where no obvious neuronal degeneration can be found is rendered extremely complex by the large numbers of chemically distinct, but functionally interrelated, neurotransmitter systems in the brain. The problem is well exemplified by the relatively little progress that has been made in understanding the etiologies of the psychoses despite the many years of intense research effort. An additional difficulty in the dystonia field is the relative scarcity of postmortem tissue available for examination. It thus seems incumbent upon researchers in the field to garner whatever clues they may from the available literature. Each reader of the literature will probably form his own opinion as to the most fruitful brain regions and chemical avenues for research. This review seems to suggest, however, that the following brain regions may deserve the closest scrutiny for possible detection of a lesion: basal ganglia--including the zona incerta--with particular emphasis on the putamen red nucleus and surround vestibular nuclei nucleus of Cajal nucleus fastigii parabrachial area sensorimotor cortex Other regions worth attention are the spinal cord, premotor area, motor cortex and thalamus. It is even more difficult to decide on the types of chemical or histochemical assays that should receive priority. Recent work indicating that immunohistochemical staining for the immune complex glycoprotein HLA-DR can readily reveal areas of active neuronal degeneration, not detected by the usual histological methods, in a number of progressive neurological diseases suggests that such staining should be tried in dystonic brains. The hints in the literature that dystonic symptoms may be provoked or exacerbated by autoimmune processes would be further reason to undertake such staining. It is this literature which has already led Sandyk et al. to suggest that hypothalamic dysregulation of immune responses might be of fundamental importance in focal dystonia.(ABSTRACT TRUNCATED AT 400 WORDS)