A discussion of movement disorders.

Disorders of movement lie at the heart of neurology. They are visible everywhere, eg in the market place, the theater, bus stations, and bedside. They are Gestalts; intersection of age, experience, and illness. They can be categorized and sometimes treated. Movement disorders are adversely affected by alcohol, drugs, lack of sleep, fevers, stress, age, and trauma. The presence of a movement disorder means less redundancy or capacity to handle additional trouble. For the individual with a movement disorder public persona, feelings, embarrassment, and triumphs are all part of the picture.

Dizziness.

Dizziness is a term that means different things to different people. In this paper, dizziness from inner ear difficulties shall be taken as synonymous with vertigo, a sense of spinning in space coupled with being unsteady afoot, nauseated, and usually in a spacey, distracted state of mind. Dizziness from a drop in cerebral blood flow shall be equated as a consequence of orthostatic hypotension, productive of lightheadedness or syncope. and involving a wide variety of pathophysiologies eg, heart, vascular reflexes, hypoxemia, hypoglycemia, anemia, etc. In a state of dizziness one cannot work or think straight. The fact that vertigo and orthostatic hypotension can be both cause and consequence of head injuries is the hard truth that commands our attention.

The perilymph fistula syndrome defined in mild head trauma.

Neurological and neuro-otological studies were carried out on 102 adults with mild cranio-cervical trauma productive of positional vertigo and perilymph fistula as confirmed by laboratory tests, and by the finding of perilymph fistula at tympanotomy in the surgically managed group. In this patient group, all other neurological and neuro-otological diagnoses were excluded, e.g. epilepsy, cerebral palsy, multiple sclerosis, retardation; and for the neuro-otological group those with a history of ototoxicity, labyrinthitis, Meniere's disease, chronic ear infections, or developmental or familial disorders. Emphasis in this study was on mild trauma: fewer than half of the sample had been rendered unconscious in the injury of record, and a third of the cases were of whiplash type, with no loss of consciousness (LOC) and no remembered headstrike. These concomitant lesions comprise the perilymph fistula syndrome (PLFS) with a unique profile of neurological, perceptual, and cognitive deficits resembling a post-concussion injury. A complete description of the clinical picture is given, including psychological, cognitive and diagnostic tests, and the outcome of bedrest vs. surgical management. PLFS can arise from minor trauma, fistula are frequently bilateral (71/102), a mild sensorineural hearing loss is of variable occurrence (53%), secondary hydrops is not uncommon, and women appear more vulnerable than men for developing the syndrome. As based upon combined laboratory techniques and clinical symptomology, fistula were correctly predicted in 61 of 65 laser-operated ears. The positional vertigo component of PLFS was in all cases managed according to a special physical therapy program utilizing exercises for vestibular symptom habituation. Even when diagnosed late, a good-to-excellent outcome was achieved in 70% of treated patients.

Disorderly walks.

The author provides a quantitative language for analysis of metric and structural errors in walking and divides motor disturbances into program and nonprogram disorders. There is extensive discussion of treatable ataxias.

Fastigial unit activity during voluntary movement in primates.

To examine the proposition that fastigial n. of cerebellum provides a fast feedback pathway to suprasegmental structures for spinal information regarding movement. Macaca irus were trained to make flexion and/or extension voluntary wrist movements. Fastigial neuron activity was then correlated with force, velocity, handle position and with shoulder or forearm muscle activity. From 200 units (75% participating), our data establish that fastigial neurons are uniformly recruited after movement onset, processing force-velocity information. Units were found specifically correlated with force or velocity alone. Fastigial activity is strategically placed to provide a 'correction' signal path for motor performance.

Progressive supranuclear palsy: functional analysis of the response to methysergide and antiparkinsonian agents.

Twelve patients with progressive supranuclear palsy were treated with methysergide; the response was monitored with videotaped examination, electrooculography, and psychometric assessment. Used alone and with antiparkinsonian agents, methysergide improved the quality of life in eight patients for 6 months to 2 years. Benefits were especially dramatic in four patients with severe dysphagia. The disorder of visually guided behavior included abnormal orienting responses, visuosocial expression and regard, and visual search. Mesencephalic visuomotor centers appear to be important not only in control of ocular motility but also in the elaboration of visually guided behavior and the orienting of spatial attention.

Responses of primate dentate neurons to different trajectories of the limb.

The activity of neurons in the dentate nucleus of the squirrel monkey was studied during the execution of a controlled, sequential movement that required different trajectories of the forearm. Examination of 207 dentate neurons ipsilateral to the performing limb revealed that over 80% of the neurons isolated were distinctly correlated with performance. The majority of these neurons had a tonic discharge pattern that usually increased coincident with the start of the movement and was maintained throughout most of the performance. A smaller group of cells ahd a burst of activity that was restricted only to a narrow part of the performance. About 30% of the tonic neurons altered their pattern of discharge whenever different limb trajectories were required, but burst cells showed exxentially no change. Detailed analysis of spike patterns revealed that no dentate neurons were phasically correlated with individual flexion-extension cycles of the performance sequence. Dentate neurons appear to be related to some general function of motor performance rather than the actions of joints or muscles used to execute the task.