Neurology in frontier America before Mitchell: Fort Scott records.

The American Civil War and Weir Mitchell were instrumental in the birth of American clinical neurology. Before this period, medical practice in frontier America was undisciplined and inchoate. In these times, Fort Scott, a federal military outpost in what was then Indian territory (now Kansas), maintained an active hospital. At this fort, meticulously kept records between the years of 1842 and 1853 have been preserved. These records reveal that military surgeons of that day were aware of several neurological illnesses, such as post-traumatic epilepsy, cephalalgia, meningitis and delirium tremens. There are autopsy descriptions of cerebral hemorrhage and meningitis. The fort surgeons used thermometry routinely, at least before autopsy, even though clinical thermometer usage was very uncommon until the late 1860s. The Fort Scott records provide insight into the prevailing clinical beliefs of the day. They also reveal that some knowledge of neurology was extant before Mitchell, even in frontier America.

A core electronic medical library in a rural setting: update.

In rural areas an electronic medical library is one of the most effective ways of staying abreast of advances in clinical medicine. A health care provider's educational needs for staying current are best met by a combination of CD-based textbooks and an inexpensive on-line database. Since publication of this review last year, several beneficial changes have occurred. In general, they are: greater availability of fast data transmission rates, wider selection of databases to choose from, both on-line and off-line, the feasibility of obtaining toll-free access numbers in selected instances, and the elimination of daytime higher connect rates. This update discusses some of these changes.

Human middle-latency auditory evoked potentials: vertex and temporal components.

We recorded middle-latency (20-70 msec) auditory evoked potentials (MLAEPs) to monaural and binaural clicks in 30 normal adults (ages 20-49 years) at 32 scalp locations all referred to a balanced non-cephalic reference. Our goal was to define the MLAEP components that were present at comparable latencies and comparable locations across the subject population. Group and individual data were evaluated both as topographic maps and as MLAEPs at selected electrode locations. Three major components occurred between 20 and 70 msec, two well-known peaks centered at the vertex, and one previously undefined peak focused over the posterior temporal area. Pa is a 29 msec positive peak centered at the vertex and present with both monaural and binaural stimulation. Pb is a 53 msec positive peak also centered at the vertex but seen consistently only with binaural and right ear stimulation. TP41 is a 41 msec positive peak focused over both temporal areas. TP41 has not been identified in previous MLAEP studies that concentrated on central scalp locations and/or used active reference electrode sites such as ears or mastoids. Available topographic, intracranial, pharmacologic, and lesion studies indicate that Pa, Pb and TP41 are of neural origin. Whether Pa and/or Pb are produced in Heschl's gyrus, primary auditory cortex, remains unclear. TP41 is probably produced by auditory cortex on the posterior lateral surface of the temporal lobe. It should prove of considerable value in experimental and clinical evaluation of higher level auditory function in particular and of cortical function in general.

Chronic exposure of primates to 60-Hz electric and magnetic fields: III. Neurophysiologic effects.

The neurophysiologic effects of combined 60-Hz electric (E) and magnetic (B) fields, of magnitudes comparable to those produced by high-voltage powerlines, were investigated in 10 monkeys (Macaca nemestrina). Six animals (experimental group) were each exposed to three different levels of E and B fields: 3 kV/m and 0.1 G, 10 kV/m and 0.3 G, and 30 kV/m and 0.9 G. Field exposures were preceded and followed by sham exposures, during which factors of field generation were present (e.g., heat, vibration, noise, etc.) without E and B fields. Each of the five segments (i.e., the three exposure segments and the initial and final sham exposure segments) lasted 3 weeks. Animals were exposed for 18 h/day (fields on at 1600 h, off at 1000 h). Four other animals (external control group) were given sham exposure for the entire 15-week period. Auditory, visual, and somatosensory evoked potentials were recorded twice a week, during the daily 6-h field-off period. E- and B-field exposure had no effect on the early or mid-latency evoked potential components, suggesting that exposure at these levels has no effect on peripheral or central sensory afferent pathways. However, there was a statistically significant decrease in the amplitudes of late components of the somatosensory evoked potential during the 10kV/m and 0.3 G, and 30 kV/m and 0.9 G exposure levels. This result is possibly related to the opiate antagonist effect of electromagnetic field exposure reported by others.

Central nervous system involvement in blue-rubber-bleb-nevus syndrome.

The blue-rubber-bleb-nevus syndrome is an uncommon neurocutaneous disorder where scattered, bluish, rubbery nevi occur on the body surface. These nevi are frequently noticeable at birth. In addition to the skin lesions, vascular malformations of internal organs, which tend to bleed, are frequently present. However, well-documented central nervous system angiomata are rarely encountered. We present herein the case of a young adult with central nervous system involvement. Patient presented with a slowly progressive ataxia and brain stem signs. A large posterior fossa, and multiple smaller hemispheric angiomata were noted. Only a very few well-described symptomatic cases have been reported in the literature; we have reviewed them here. Unlike these cases, our patient with extensive nervous system involvement had a chronic, slowly progressive and nonfatal course.

Muscle pathology in Bassen-Kornzweig syndrome and vitamin E deficiency.

A constellation of histologic abnormalities was demonstrated in the quadriceps femoris muscle of a 29-year-old man with Bassen-Kornzweig syndrome. The abnormalities consisted of fibers containing dense lipid inclusions ceroid and lipofuscin, a spectrum of fiber size, architectural changes, and an increase in central nuclei. A dramatic shift of fiber type predominance, from type I to type II, was demonstrated in the myosin ATPase reactions one year after vitamin E therapy. Despite an apparent reduction in the number of fibers containing lipid and ceroid granules in the second biopsy, neuromyopathic changes worsened. The relationship of these findings to vitamin E therapy is discussed.

The spectrum of neurologic disorder from vitamin E deficiency.

We describe nine patients with fat malabsorption in whom a spectrum of vitamin E deficiency was present. Early deficiency was generally asymptomatic, and intermediate deficiency produced some impairment. Ataxia, weakness, reflex changes, impaired vision, and pigment retinopathy were associated with chronic, advanced deficiency. In the last group, delayed central somatosensory conduction and amplitude reduction of the electroretinogram were present. In adults, a severe vitamin E deficiency state existed for more than 5 years before producing measurable neurologic damage. The clinical picture is less homogeneous than previously suggested, and electrophysiologic abnormalities need not predate clinical dysfunction.

Predictive value of laryngeal electromyography in patients with vocal cord paralysis of neurogenic origin.

Laryngeal electromyography can provide prognostic information when evaluating patients with vocal cord dysfunction. Twenty-four patients were studied to determine the predictive capacity of this test. Six patients had bilateral vocal cord paralysis, constituting a total of 30 vocal cords examined. Sixteen of these cords had decreased or absent motor unit potentials, fibrillations, or positive waves. None of these patients recovered function. Fourteen cords demonstrated either normal motor unit or polyphasic potentials. Return of mobility was evident in 11 of these cords. The combined total was 27 of 30 cords correctly predicted, demonstrating a 90% accuracy rate.

Cerebellar hemorrhage. A review and reappraisal of benign cases.

We reviewed 17 cases of cerebellar hemorrhage that occurred in our institutions over a five-year period. Nine of these patients had a benign immediate outcome, recovering without surgery. One patient died four weeks later of septicemia. We reviewed the clinical and radiological features of benign cases from our institutions and from the literature. Our results indicate that there is no single determinant that will confidently predict such a benign outcome in a given patient. The size of the hemorrhage, its location, and the level of consciousness of the patient had no consistent bearing on outcome. However, marked hydrocephalus or deteriorating level of consciousness indicated a poor prognosis, irrespective of the choice of therapy. Benign outcomes were not confined only to those who were alert or had small laterally placed hemorrhages. We were able to identify unequivocal hypertension, preceding the hemorrhage, in only four of our 17 patients.

Psychoacoustic and electrophysiologic effects of partial eighth nerve damage.

The authors present psychoacoustic and electrophysiologic data concerning a patient with partial damage to the auditory nerve, presumably from a dilated arterial vessel. The lesion was described and documented during neurosurgery for vestibular nerve decompression. Pure tone thresholds, psychoacoustical tuning curves, speech reception ability for spondaic words, maximum word recognition performance for monosyllabic NU-6 word lists, and performance on the synthetic sentence identification test in the ipsilateral and contralateral competing message modalities were normal. Findings consistent with eighth nerve dysfunction, absent contralateral acoustic reflexes, absent or unrecognizable early evoked potentials occurring in the first 10 msec, brainstem auditory evoked potentials (BAEPs), and slight rollover of the performance intensity function for monosyllabic words were obtained on the involved side. In spite of the grossly abnormal BAEPs, two late, presumably cortical, auditory evoked potential components, which occur in the 60 to 250-msec range--vertex potential and T complex--were present and normal. The findings indicate that the perceptual processes needed for speech reception and recognition and for the appearance of later, presumably cortical-evoked potentials can be preserved despite partial damage to the auditory nerve.

Late auditory evoked potentials can occur without brain stem potentials.

The sequence of early, middle and late auditory evoked potentials is well known. However, it is unknown whether the late (60-250 msec) potentials can occur independently of the early, brain stem potentials. Therefore, in 6 subjects with markedly abnormal or absent brain stem potentials, we recorded two of the late potentials: the vertex potential and the T-complex. The latter is a putative product of auditory cortex. Both of these potentials were clearly evident in all patients in spite of the absence of or marked abnormalities in brain stem potentials.

Reversible neurological symptoms caused by vitamin E deficiency in a patient with short bowel syndrome.

The effect of vitamin E deprivation on the fully developed human nervous system is not known. In children with fat malabsorption from various causes neuropathological and neurological changes have been ascribed to vitamin E deficiency. Herein we described a neurological deficit that occurred in a 64-yr-old man with chronic steatorrhea leading to severe vitamin E deficiency. long-term supplementation with vitamin E resulted in clinical improvement beginning a few months after normalization of his vitamin E status.

Legionnaires' disease. Report of a case with unusual manifestations.

The multisystem involvement in Legionnaires' disease commonly includes pulmonary, renal, hepatic, gastrointestinal tract, and neurologic manifestations, but except for the lung the mechanism of disease has not been defined. Circulating toxins are most commonly implicated. A nonfatal case is reported here that had unusual renal and neurologic findings. The renal failure was associated with urinary findings indicative of a glomerulitis, and the major neurologic manifestation was a polyneuropathy. The complications in this case suggest an immunologic mechanism for the extrapulmonary manifestations of Legionnaires' disease.