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Biomedical subjects

C W Hess

Publications and source records attributed to C W Hess.

124 records · Page 7Linked to original sources
PubMed1986

Thalidomide-induced peripheral neuropathy. A prospective clinical, neurophysiological and pharmacogenetic evaluation.

Prospective clinical and electrophysiological follow-up was performed on nine patients under thalidomide treatment in order to detect the very beginning of possible drug-induced peripheral neuropathy. For neurophysiological assessment, nerve conduction measurements of the median, peroneal and sural nerves (7 conduction parameters) and needle EMG examination of the anterior tibial muscle were performed. The results of a first control after about 3 months of treatment were compared with the starting point examination, and the patients were then classified as "affected" or "not affected" according to clinical and neurophysiological criteria. At this point, three patients showed clinical and electrophysiological, and another two only electrophysiological alterations suggesting early neuropathy. This classification did not change after further clinical and electrophysiological controls. Without starting-point values, the early detection of neuropathy would not have been possible in all patients. No single reliable neurophysiological parameter for detection of thalidomide-induced neuropathy could be found. Pharmacogenetic classification with regard to hydroxylation and acetylation phenotypes was then performed in some patients and interpreted with relation to thalidomide neurotoxicity. A possible relationship between slow acetylators and development of thalidomide-induced neuropathy was found.

Acetylation↗
PubMed1986

Reactions of college students to speech disorders.

This study investigated the reactions of college students to audiotaped speech samples of a woman simulating moderate speech disorders of stuttering, hypernasality, and lateral lisping, as well as presenting normal speech. Student reactions to these recordings were measured by a figure placement task and a 30-item semantic differential instrument. The students reacted to the speech disorders with a tendency of increased social distance in addition to judgments of lower evaluation, lower understandability, and higher anxiety. These findings suggest that students react negatively to speech disorders. Awareness of such reactions could facilitate clinical effectiveness and prepare clinicians to protect clients' rights.

Adult↗
PubMed1986

Sample size and type-token ratios for oral language of preschool children.

This study investigated the stability of five type-token ratios (TTRs) in 50-utterance oral language samples segmented into nine lengths. The samples were obtained from 83 children, 3, 4, and 5 years of age. The five TTRs included the basic type-token ratio, the corrected type-token ratio, the root type-token ratio, the bilogarithmic type-token ratio, and the Characteristic K. The sample segment sizes consisted of the first, second, third, and fourth 50-word segments; the first and second 100-word segments; the first 150-word segment; the first 200-word segment; and the total 50-utterance sample. Based on the results of this study, TTR measures on the language of young children should not be compared for samples that differ in number of words. Further, TTR measures for sample size of 50 and 100 words have reliabilities that are judged to be inadequate for research or clinical purposes. The size of the language sample needed for minimum reliability of .70 is 350 words. Greater reliability requires larger word-sample size.

Child Language↗
PubMed1986

Perhexiline-induced lipidosis in the dark Agouti (DA) rat. An animal model of genetically determined neurotoxicity.

Perhexiline maleate, an antianginal compound, may cause severe adverse effects such as weight loss, hepatic dysfunction and peripheral neuropathy in a small proportion of patients. Since present evidence suggests that poor debrisoquine hydroxylators are at risk, we designed an experimental study comparing its neurotoxic effects in dark Agouti (DA) rats, with poor hydroxylation of debrisoquine with that in Sprague Dawley (SD) rats, which are vigorous hydroxylators. Light and electron microscopic investigations revealed neurotoxic changes in DA rats after cumulative doses which did not cause any changes in SD rats. Although there was no evidence of hepatic disturbance, morphological examination disclosed a heavy lipid deposition in neurons of dorsal root and sympathetic ganglia in DA rats. This was correlated with increased plasma and tissue concentrations of the drug. The lipid accumulation was similar to that observed in man with perhexilene-induced neuropathy. Our results suggest that perhexilene neurotoxicity in the DA rat is related to a genetically determined impairment of hydroxylation. The DA rat may serve as an animal model for investigating the potential neurotoxicity of drugs which are metabolized by hydroxylation of the debrisoquine type.

Animals↗
PubMed1986

Severe adult hypersomnia--sleep apnea syndrome in craniofacial dysostosis.

Polysomnography and blood gas measurements during sleep in a young man with craniofacial dysostosis, who presented with an extremely severe sleep apnea syndrome, are reported. Tracheostomy relieved all his complaints permanently, namely hypersomnia, deteriorated intellectual performance, automatic behaviour with hypnagogic hallucinations and snoring. Laboratory results also returned to normal. The polygraphic data of night sleep (and daytime naps) before and after surgery suggest that hypersomnia was primarily caused by severe nighttime oxygen desaturations and that the hypnagogic hallucinations were caused by apnea-induced chronic REM sleep deprivation. Furthermore, the periodic variation of central respiratory drive, which was also abolished after surgery, is interpreted as the cause of apnea-induced fluctuations between sleep stages in this case.

Adult↗
PubMed1986

[Interactive microcomputer program for calculation and normal values for routine clinical neurophysiological research].

A BASIC program for a 128 KByte microcomputer is described which is deviced to support every day clinical neurophysiological investigations. It provides calculating routines and normal values with a hard copy print option for visual, auditory, and somatosensory evoked potentials, peripheral motor and sensory nerve conduction velocities, and needle EMG potential analysis. All important arm and leg nerves and muscles are included. By its simplicity the program gives easy access to changes according to individual requirements.

Computers↗
PubMed1985

Visual evoked response abnormality in myoclonus epilepsy with large pupils. Occurrence in a family with acorpuscular myoclonus epilepsy.

Flash and pattern evoked responses were recorded from three siblings with myoclonus epilepsy who all had strikingly large pupils in daylight. Comparison with the visual evoked responses (VERs) of 15 normal and eight epileptic control subjects (including one with myoclonus epilepsy but normal pupils) disclosed a substantial reduction of the amplitude of the flash response as compared with the normal pattern response in these three patients. It is suggested that the VER constellation and the pupillary abnormality, together with the normal electroretinogram and diffusely distributed relative scotomas, were due to a ganglion cell loss in the retina.

Adult↗
PubMed1984

[Narcoleptic syndrome].

Only in the last century was the narcoleptic syndrome recognized as a distinct entity fundamentally different from epilepsy. It is characterized by increased daytime sleepiness, usually as short sleep attacks, and by cataplexy. The latter is reflected in attacks of fully or incompletely developed loss of muscle tone, and in distressing akinetic states (so-called sleep paralysis) which chiefly occur in transition states between wake and sleep. In about half the patients, excessive daytime sleepiness may manifest itself in twilight states of lowered vigilance with automatic behaviour and amnesia. Many narcoleptics suffer from hallucinations, which may occur as they are falling asleep, during sleep paralysis, cataplectic attacks, and daytime sleepiness. Knowledge of the pathogenesis of narcoleptic disturbances is still incomplete but has been essentially widened by the discovery of paradoxical sleep, because cataplexy, sleep paralysis and hypnagogic hallucinations may now be interpreted as dissociated paradoxical sleep phenomena. The treatment of narcolepsy comprises advice in appropriate daily regimen, nutrition and vocational orientation as well as medication by stimulating agents for hypersomnolence and by tricyclic drugs for cataplexy.

Arousal↗
PubMed1982

Visual evoked potentials in acute occipital blindness. Diagnostic and prognostic value.

Pattern-evoked and flash-evoked responses were recorded from four patients with acute blindness due to occipital ischaemia. No responses could be obtained with pattern stimulation. Flash stimulation, however, yielded well-reproducible potentials in all four cases in spite of practically complete visual loss. In one patient vision recovered completely while the three others showed poor or minimal recovery in restricted visual field areas only. It is concluded that the flash method is not appropriate for differentiation of occipital blindness from psychogenic visual disorders. Furthermore, preserved flash-evoked potentials in the acute stage of occipital blindness cannot be taken as a reliable prognostic sign for visual recovery, as has been postulated by others. A possible extrastriate origin of these flash responses is discussed in view of recent theories on a second visual system.

Adult↗
PubMedDate not supplied

Central motor conduction studies in motor neurone disease using magnetic brain stimulation.

Central motor conduction (CMC) to abductor digiti minimi (ADM) was evaluated in 22 patients with motor neurone disease (MND) using magnetic stimulation of the motor cortex and electrical stimulation at the C7/T1 interspace. CMC was abnormal in 14 patients; prolonged CMC time and absence of response to brain stimulation were more frequent abnormalities than low amplitude responses without prolonged CMC time. The technique can reveal subclinical upper motor neurone involvement and document central motor pathway dysfunction in MND. The patterns of abnormality are not specific to MND; all may occur in other neurological disorders including multiple sclerosis.

Adult↗
PubMedDate not supplied

F responses and central motor conduction in multiple sclerosis.

Two electrophysiological investigations were used to study 18 patients with multiple sclerosis--F wave characteristics including amplitude, persistence and frequency, which can provide a measure of motoneurone excitability, and magnetic stimulation of the cortex, which enables measurement of conduction along central motor pathways. There was an increase in the mean amplitude and persistence of the F response in patients with abnormal central motor conduction (CMC), although no correlation between the degree of abnormality of CMC and increase in F response amplitude was found. Increase in mean amplitude and persistence of the F response were also found in patients with normal CMC but clinical evidence of a UMN disorder (spasticity and/or weakness); there was no correlation, however, between any single F response characteristic and any particular clinical sign. CMC appears to be the preferred test for detecting subclinical motor lesions in MS: of the patient sides with normal clinical examination, 36% showed abnormal CMC, whereas 23% showed abnormal F responses.

Adult↗
PubMedDate not supplied

Supervisors' use of social power with graduate supervisees in speech-language pathology.

This investigation discusses social power as an identifiable and measurable aspect of the supervisory process in speech-language pathology (SLP). This study examined the use of French and Raven's (1959) types of social power by 61 clinical supervisors with their 69 beginning and 69 advanced graduate supervisees from 14 university programs. Both supervisors' and supervisees' perceptions of supervisors' use of expert, referent, coercive, legitimate, and reward power were obtained with modified versions of the Rahim Leader Power Inventory (RLPI) (Rahim, 1988). The supervisors' perceptions of their use of the five types of social power with beginning supervisees were not significantly different from the beginning supervisees' perceptions. By contrast, the study yielded discrepant perceptions of supervisors' use of social power with advanced supervisees. Further, supervisors reported differential use of power with supervisees with different amounts of clinical experience. Yet, the perceptions of beginning and advanced supervisees did not differ relative to supervisors' use of any of the five types of social power. These findings can sensitize clinical supervisors to the sources of social power inherent in their practice.

Adult↗