Quadriparesis and nuclear oculomotor palsy with total bilateral ptosis mimicking coma: a mesencephalic 'locked-in syndrome"?

Upper lid and vertical eye movements are usually preserved in patients with the "locked-in" syndrome, a condition manifested by anarthria, spastic quadriparesis, and intact mental function, and caused by lesions in the ventral portion of the pons. We describe a presumed mesencephalic "locked-in" syndrome in a patient who had total bilateral ptosis at the onset of his disease and later on experienced complete bilateral oculomotor nerve paralysis.

The syndrome of 'continuous muscle fiber activity.'.

A 7-year-old boy who suffered from increasing stiffness and contractures of the extremities had distally pronounced atrophy and absent tendon reflexes. Electromyography showed continuous electrical activity during rest, sleep, after intravenous injection of diazepam, and after peripheral nerve block. The H reflex was elicitable; the silent period after the reflex was absent. Histopathological examination of the peroneus muscle disclosed a marked preponderance of type I fibers and slight atrophy of the type II fibers. Electron microscopic examination of the endplates demonstrated a marked atrophy of the postsynaptic regions and widened synaptic clefts. After one year's treatment with phenytoin, 200 mg daily, the patient showed an almost normal muscle tone. As not all of these electrophysiological phenomena can be fully explained by disturbances of the nerve terminals or the endplates, a further anomaly proximal from the peripheral nerve block seems to have been present.

Nontraumatic spinal epidural and subdural hematomas.

Ten patients with a nontraumatic spinal extramedullary hematoma are reported, nine of the hematomas localized in the epidural space. Seven of the patients were taking anticoagulant drugs and five showed signs of liver disease, mostly due to alcoholism. The invariable first symptom was an intense local pain in the spine, followed in all but one case by radicular irradiation and in all by bladder disturbances and sensory and motor deficits of the spinal cord or cauda equina. All the patients had myelography to verify the spinal mass and were operated on as fast as possible. The outcome depended mainly on the preoperative neurologic status. If there was only an incomplete sensory and motor lesion before the operation, the patients recovered fairly well or completely. The patients who did not become capable of walking again were completely paralytic preoperatively.

Autonomic dysfunction in botulism B: a clinical report.

Nine cases of botulism B with preponderant effects upon cholinergic autonomic innervation are presented. Blurred vision and dry mouth were constant symptoms. Impairment of salivary and lacrimal secretion were detectable for months. In the absence of clinical signs, electromyographic studies did not reveal neuromuscular involvement. Administration of antitoxin in the late course of such cases is not recommended, but guanidine can be used. Doubt is cast upon a new clinical entity called "acute autonomic neuropathy."

Donepezil and flight simulator performance: effects on retention of complex skills.

We report a randomized, double-blind, parallel group, placebo-controlled study to test the effects of the acetylcholinesterase inhibitor, donepezil (5 mg/d for 30 days), on aircraft pilot performance in 18 licensed pilots with mean age of 52 years. After 30 days of treatment, the donepezil group showed greater ability to retain the capacity to perform a set of complex simulator tasks than the placebo group, p < 0.05. Donepezil appears to have beneficial effects on retention of training on complex aviation tasks in nondemented older adults.

Context processing in older adults: evidence for a theory relating cognitive control to neurobiology in healthy aging.

A theory of cognitive aging is presented in which healthy older adults are hypothesized to suffer from disturbances in the processing of context that impair cognitive control function across multiple domains, including attention, inhibition, and working memory. These cognitive disturbances are postulated to be directly related to age-related decline in the function of the dopamine (DA) system in the prefrontal cortex (PFC). A connectionist computational model is described that implements specific mechanisms for the role of DA and PFC in context processing. The behavioral predictions of the model were tested in a large sample of older (N = 81) and young (N = 175) adults performing variants of a simple cognitive control task that placed differential demands on context processing. Older adults exhibited both performance decrements and, counterintuitively, performance improvements that are in close agreement with model predictions.

Relationship of age and simulated flight performance.

OBJECTIVE: To determine the relationship between age and aviator performance on a flight simulator. DESIGN: A cross-sectional observational study. PARTICIPANTS: The sample consisted of 100 aviators aged 50 to 69 (mean = 58). MAIN OUTCOME MEASURES: Pilots were tested on a Frasca 141 flight simulator (Urbana, IL), linked to a UNIX-based IRIS 4D computer (Silicon Graphics, Mountain View, CA), which both generated graphics of the environment in which the pilots flew and collected data concerning the aircraft's flight conditions. RESULTS: We found that increased age was significantly associated with decreased aviator performance on a flight simulator. CONCLUSIONS: Although there was a significant relationship between increased age and decreased aviator performance, age explained 22% or less of the variance of performance on different flight tasks; hence, other factors are also important in explaining the performance of older pilots.

Influence of nicotine on simulator flight performance in non-smokers.

In a placebo-controlled study, we investigated the influence of nicotine on late-day aviation performance in 15 non-smoking subjects. In a within-subjects design, subjects were tested on 2 days, each lasting 8 h and consisting of three 75-min simulator flights (late-afternoon practice, evening test, night test). Prior to each test, subjects received either nicotine polacrilex 2 mg or placebo gum. As expected, overall performance was significantly better after nicotine, compared to placebo (P < 0.01). Post-hoc analysis of individual flight tasks showed that nicotine improved scores on approach to landing, a task which appears to require sustained attention. We conclude that nicotine may improve late-day flight performance in non-smoking aviators.

Relationship between variations in estradiol and progesterone levels across the menstrual cycle and human performance.

RATIONALE: Studies about whether or not the cognitive performance of women is influenced by changes in levels of sex steroid hormones across the menstrual cycle have produced ambiguous results. OBJECTIVES: This study tested whether flight simulator performance differs significantly between the menstrual and the luteal phase of the menstrual cycle. METHODS: In a within-subjects design, 24 female pilots were tested twice during their menstrual cycle: once during the menstrual and once during the luteal phase. On both test days they performed a 75-min simulator flight in a Frasca 141, a popular pilot training device. RESULTS: Despite highly significant differences in estradiol (E2) as well as progesterone (P) levels on the 2 test days, and despite excluding subjects with anovulatory cycles from the analyses, there were no significant differences in overall flight performance between the menstrual and luteal phases. We found no significant correlations between E2 or P levels and flight performance. CONCLUSIONS: We found no evidence that the tested menstrual cycle phases and their associated E2 and P levels significantly influence flight simulator performance. We consider these negative findings based on 24 subjects meaningful because previous studies on the influence of menstrual cycle on cognitive performance have not involved complex "real world" tasks such as piloting an aircraft and they obtained inconsistent results.

Giant cell arteritis (cranial arteritis, polymyalgia rheumatica).

Giant cell arteritis, which is probably due to disturbed immune mechanisms, has a spectrum of clinical symptoms in elderly people. In nearly all cases such general signs as loss of appetite, loss of weight and fever are present. The sedimentation rate is almost without exception about 100 mm in the first hour. The two most frequent and typical clinical syndromes are polymyalgia rheumatica and cranial arteritis. The polymyalgia rheumatica is characterized by periarticular pain which is mostly symmetrical and accentuated in the shoulder girdle. Increasingly severe temporal headache and ocular distrubances are found with cranial arteritis in more than 50% of cases. A combination of both diseases is frequent. Other arterial branches are rarely involved. The course of the disease is over a period of 1 1/2 to 2 years. Treatment with corticosteroids is indicated mainly because of the severe ocular complications with blindness. It should begin immediately, be intensive and last over a long period. Regular followup is necessary over several years in order to avoid relapses.

The perifascicular atrophy factor. An aid in the histological diagnosis of polymyositis.

19 biopsies of polymyositis patients were compared with 19 matched controls. The presence of smaller fibres in the periphery of the fascicles has been analyzed quantitatively using a perifascicular atrophy factor. The thinner fibres are multiplied by a factor from 1-4, considering their significance for the diagnosis of fibre atrophy. The value obtained with this method from centrally located fibres as related to the value from peripherally located ones is called the perifascicular atrophy factor. If this is less than -300 a myopathy of the group of the polymyositis/dermatomyositis can be assumed. 47 per cent of dermatomyositis biopsies and none of the controls were below this range

Paramyotonia congenita. A clinical, electrophysiological and histological study of 12 patients.

The present paper describes the clinical, electrophysiological and histological findings made in 12 patients belonging to 2 genealogical lineages in Switzerland, suffering from paramyotonia congenita. This is the first report of this disease in Switzerland. The myopathy, transmitted by autosomal dominant inheritance, is characterized by a typical past medical history and by the persistent contraction of the muscles of the face, arms and legs provoked by exposure to cold. Also of diagnostic importance are the myotonic reactions inducible at room temperature, such as percussion myotonia, active myotonia and paradoxical myotonia. During paramyotonic episodes provoked by exposure of the subjects in a refrigeration chamber, serum potassium concentrations remained within normal limits. Potassium loading producing serum levels above 6 mEq/1 in 2 patients gave rise to stiffness and weakness of the arms and legs, but no signs of paralysis. Induced hypokalemia in 3 cases caused no paramyotonic symptoms. Electromyographic recordings in 5 patients showed myotonic discharges, which disappeared upon cooling of the limb, giving way to progressive muscular stiffness. Histological, histochemical and electronmicroscopical examination of the muscle tissue revealed only diagnostically unspecific myopathological changes.

Intracranial giant cell arteritis.

A case of giant cell arteritis of intracranial vessels diagnosed by autopsy is described. Giant cell arteritis of the proximal basal brain arteries was exceptionally marked in a man of 60 years. The clinical course, laboratory findings and the pathological alterations of the brain and intracranial blood vessels are described. The case is discussed on the basis of the literature on giant cell arteritis with cerebral symptoms as well as on granulomatous giant cells arteritis of the brain. A separation of these two entities does not seem justified.

The Landry-Guillain-barré syndrome. Complications, prognosis and natural history in 123 cases.

One hundred and twenty-three patients, 68 males and 55 females in whom acute polyradiculitis Guillain-Barré appeared at an age of between 1,6 and 76 years were re-examined after 0.9 to 12.3 years. The initial symptoms, the signs during the acute phase, in particular the cranial nerve signs and central nervous signs, as well as findings in the cerebrospinal fluid and complications are described. Three patients died during the acute phase. At follow-up only 57% of the patients were completely cured. In 22% motor signs, mainly distal in the lower extremities were found. Only 6 of these patients however were handicapped. Twenty-two patients had loss of one or more tendon reflexes, in general the ankle jerk. Only 6 showed very slight central nervous system signs. Eleven of 55 follow-up cases had pathological findings in needle electromyography. A disturbance of conduction velocity or distal latency was also found in several adults and children without residual clinical signs. The time span between the maximum of the initial signs and the beginning of recovery seemed to be particularly long in patients who showed residual signs on follow-up. These patients also seemed frequently to have had a severe tetraparesis in the initial phase. We could not confirm the therapeutic effect of cortisone or ACTH in our patients: amongst the 30 adults treated with cortisone 6 (20%) had residual signs at follow-up, whilst 5 (25%) of the 22 untreated ones had similar findings.

Effect of excipients on the stability and structure of lyophilized recombinant human growth hormone.

We have investigated the effect of mannitol, sorbitol, methyl alpha-D-mannopyranoside, lactose, trehalose, and cellobiose on the stability and structure of the pharmaceutical protein recombinant human growth hormone (rhGH) in the lyophilized state. All excipients afforded significant protection of the protein against aggregation, particularly at levels to potentially satisfy water-binding sites on the protein in the dried state (i.e., 131:1 excipient-to-protein molar ratio). At higher excipient-to-protein ratios, X-ray diffraction studies showed that mannitol and sorbitol were prone to crystallization and afforded somewhat less stabilization than at lower ratios where the excipient remained in the amorphous, protein-containing phase. The secondary structure of rhGH was determined using Fourier transform infrared (FTIR) spectroscopy. rhGH exhibited a decrease in alpha-helix and increase in beta-sheet structures upon drying. Addition of excipient stabilized the secondary structure upon lyophilization to a varying extent depending on the formulation. Samples with a significant degree of structural conservation, as indicated by the alpha-helix content, generally exhibited reduced aggregation. In addition, prevention of protein-protein interactions (indicated by reduced beta-sheet formation) also tended to result in lower rates of aggregation. Therefore, in addition to preserving the protein structure, bulk additives that do not crystallize easily and remain amorphous in the solid state can be used to increase protein-protein distance and thus prevent aggregation.

Programmed texts: success or failure? An analysis of medical students' opinions.

It is shown that German medical textbooks have sold about nine times better than programmed texts, even if they were written by the same author and on the same subject. To explore some of the reasons why programmed texts are being used so little in comparison with conventional textbooks, 4th and 5th year medical students of the University of Berne were asked to work through a short programmed text in clinical neurology and to answer questions related to several aspects of using programmed texts and other materials. The analysis of the 212 questionnaires returned (58%) indicates that almost all students considered such a learning experience as highly useful and stimulating, but only about 25 per cent had no reservations. It is concluded that programmed medical texts may be used so little because they require students to learn in a highly standardized way, and because students need additional learning resources which provide them with conceptual framework of and sufficient information about a given area.

Influence of the menstrual cycle on flight simulator performance after alcohol ingestion.

OBJECTIVE: Previous studies investigating the influence of the menstrual cycle on cognitive functioning of women after alcohol ingestion have obtained inconsistent results. The present study tested the hypothesis that flight simulator performance during acute alcohol intoxication and 8 hours after drinking differs between the menstrual and the luteal phase of the menstrual cycle. METHOD: White female pilots (N = 24) were tested during the menstrual and the luteal phases of their menstrual cycles. On each test day they performed a baseline simulator flight, consumed 0.67 g/kg ethanol, and performed an acute-intoxication and an 8-hour-carryover simulator flight. RESULTS: Subjects reached highly significant increases in estradiol (E2) as well as progesterone (P) levels during the luteal test day. Yet, there were no significant differences in overall flight performance after alcohol ingestion between the menstrual and luteal phases during acute intoxication or at 8-hour carryover. We found no correlations between E, or P levels and overall flight performance. However, there was a statistically significant Phase x Order interaction: Pilots who started the experiment with their menstrual day were less susceptible to the effects of alcohol during the second test day than were pilots who started with their luteal day. CONCLUSIONS: The tested menstrual cycle phases and varying E2 and P levels did not significantly influence postdrink flight performance. Because the present study included a comparatively large sample size and because it involved complex "real world" tasks (piloting an aircraft), we believe that the present findings are important. We hope that our failure to detect menstrual cycle effects will encourage researchers to include women in their investigations of alcohol effects and human performance.

[Tarsal tunnel syndrome. Diagnosis and differential diagnosis]. / Das Tarsaltunnelsyndrom. Diagnostik und Differentialdiagnostik.

The tarsal tunnel syndrome represents an entrapment neuropathy of the tibial nerve behind the internal malleolus under the retinaculum of the flexor muscles of the foot. In more than 3 out of 4 cases, it is a late consequence of twisting or fracture of the ankle. Local pain is increased by walking. In addition to local pain on pressure behind the internal malleolus, at a later stage paresis of the small foot muscles becomes evident with impaired abduction of the toes, decreased sensation and abnormally dry, smooth skin over the sole of the foot. The impairment of tibial nerve function can also be shown electrophysiologically. Surgical treatment is recommended for advanced cases.

[Diabetic foot--differential diagnosis from the viewpoint of the neurologist]. / Der diabetische Fuss--Differentialdiagnostik aus der Sicht des Neurologen.

This survey describes the main neurological alterations which are observed in the diabetic foot. They consist of 1) painful sensations 2) distal disturbances of sensitivity 3) absent reflexes of the Achilles tendon 4) trophic ulcers 5) impaired arterial circulation 6) deformities of toes and foot. The characteristics of these various alterations are enumerated.

Alcohol elimination and simulator performance of male and female aviators: a preliminary report.

OBJECTIVES: In this preliminary study of alcohol effects on aviators' flight simulator performance, we addressed some methodological issues regarding possible gender-related differences in response to alcohol. METHODS: Subjects were 11 male and 12 female general aviation pilots, ages 21-40. Subjects received 8 h of training before they were tested with alcohol. On the alcohol test day they were tested before drinking, while intoxicated (target BAC of 0.08%), and 8 h after drinking. RESULTS: The average, observed peak BAC readings for men and women were within 0.003% of each other. We observed faster disappearance rates for women such that women reached the FAA cutoff of 0.04% approximately 1 h before men, on average. Compared to predrink performance, there was a significant decrement in simulator performance during acute intoxication, but not 8 h after drinking. There were no significant gender differences in performance before or after drinking alcohol. Slower rates of alcohol elimination were associated with larger performance changes 8 h after drinking. This is the first report to our knowledge suggesting a possible relation between alcohol elimination rate and change in performance after drinking alcohol. CONCLUSIONS: A 12.5% dose reduction for women appears to be adequate for achieving comparable peak BAC's for male and female groups. Future studies using measures of circadian rhythmicity in conjunction with pharmacokinetic and performance measures could potentially shed light on differences in subjects' acute and delayed responses to alcohol.