PubMed Health⌕ Search

Biomedical subjects

R Hébert

Publications and source records attributed to R Hébert.

At least 73 records · Page 4Linked to original sources
PubMed1984

Permanent peripheral hearing system alteration following transient neonatal hyperthyroidism in rats.

Maturation of the peripheral auditory system was monitored with the brainstem response audiometry (BSRA) technique in L-thyroxine (T4)-injected rats. Neonatal hyperthyroidism (NH) was induced by daily injections of T4 from birth to 20 days. Following an initial period of precocious onset and accelerated maturation of click-evoked cochlear activity, specific tone stimulation triggered an altered evoked activity as soon as 16 days after birth with no recovery on the last recording session at 120 days, when the animals are considered adult. These results thus indicate that NH could rapidly lead to a permanent abnormality of peripheral auditory system evoked potentials.

Animals↗
PubMed1983

Redundancy in ascending and descending pathways mediating head turning elicited by entopenducular stimulation in the cat.

Contraversive turning movements of the head were elicited in alert cats by unilateral electrical stimulation of the entopeduncular nucleus. To determine the relative functional importance of ascending and descending pathways activated by the stimulation, the animals were submitted to thalamocortical or midbrain lesions and to combinations of the two lesions interrupting the pathways. Head turning was hindered considerably only after combinations of the two lesions and not after either lesion alone. Taking into account the results of previous studies, showing that most efferent fibers of the entopeduncular nucleus branch to the thalamus and to the midbrain, it is concluded that not only one but two main efferent pathways, corresponding to each branch, are used by the entopeduncular nucleus to control motoneurons, each pathway carrying enough redundant information to mediate head turning.

Afferent Pathways↗
PubMed1982

Influence of tetraiodothyronine on hearing maturation in rats.

Thyroid hormones are essential to the maturation of the central nervous system and sensory organs. Hypothyroidism induced various kinds of neural retardation, including hearing deficits. Despite careful attention to replacement therapy in human neonatal hypothyroidism, psychological disorders and cerebellar malfunction may occur in later life and may be related to overdoses. Brain stem response audiometry (BSRA) is used in this study as an indicator of acoustic pathway maturation in newborn rats. Normal litters are compared to tetraiodothyronine (T4)-overtreated rats from birth to day 12 of life. Onset of hearing and acoustic maturation are accelerated in treated animals as compared to controls (p less than 0.0001). Differences between groups progressively vanish after cessation of T4 administration. However, as long as 4 months later, small differences are still present, leading one to suspect a permanent change in the functioning of the acoustic pathways.

Animals↗
PubMed1980

Altered objective audiometry in aminoglycosides-treated human neonates.

To detect the eventual ototoxicity of aminoglycoside treatments in neonates, we compared brain stem response audiometry (BSRA) recordings in 15 neonates treated i.m. with either Gentamicin or Tobramycin at conventional dosages to those of 14 neonates used as a control group. All babies were housed in incubators and were comparable in gestational age (from 29 to 42 weeks). At day 0, BSRA did not significantly differ in the two groups, 90 dB latencies of the prominent wave V measured at 8.51 +/- 0.99 ms in the treated babies and 7.89 +/- 0.84 ms in the controls (p > 0.10), respectively. After 5 days of aminoglycoside treatment, the latencies of the wave V dwelled on 9.13 +/- 1.90 ms while remaining at 7.75 +/- 1.11 ms in the control group (p < 0.01). At day 10 latencies reached 8.73 +/- 1.47 ms in treated babies as compared t 7.31 +/- 1.06 ms in controls (p < 0.01).

Aminoglycosides↗
PubMedDate not supplied

Attention deficits: is there a right hemisphere specialization for simple reaction time, sustained attention, and phasic alertness?

Impairments of attentional focus often are claimed to be associated with lesions of the right hemisphere. Although some studies comparing right- and left-brain-damaged patients have supported this idea, others have not found differences between these patients in various attention tasks. The present study was carried out in order to further investigate the putative role of the right hemisphere in a simple reaction time task, a sustained attention task, and a phasic alertness task. Subjects were 46 patients with right-hemisphere lesions and 37 patients with left-hemisphere lesions. Results showed no difference between right- and left-brain-damaged patients in simple reaction time, in speed of response over time (sustained attention), and in the capacity to prepare to an uncoming stimulus (phasic alertness). Future studies will have to use a more precise categorization of lesions than only right-versus left-brain damage.

Adult↗
PubMedDate not supplied

The impact of a support group programme for care-givers on the institutionalisation of demented patients.

Support group programmes have been proposed to alleviate the care-givers' burden and postpone institutionalisation of demented patients. Experimental studies on these programmes failed to detect any impact on care-givers' burden, but none have examined the effect on institutionalisation. The objective of this paper is to assess the impact of a support group programme for care-givers on the institutionalisation of demented patients. Forty-five care-givers of community-dwelling demented patients were allocated randomly to the study group (n = 24) and the control group (n = 21). Subjects in the study group attended a structured programme of 8 weekly sessions of 3 h each. Subjects assigned to the control group were referred to the informal monthly meetings of the Alzheimer's Society. Using survival analysis, the median length of time until institutionalisation was 30 months from the time of the entry into the study. At 24 months, the probability of being institutionalised was 0.33 in the study group and 0.45 in the control group. This difference was not statistically significant (log-rank test: chi2 = 1.02; P = 0.31). These results emphasize the lack of scientific evidence about efficacy of such programmes and the need for a large multi-centre study on this topic.

Journal Article↗
PubMedDate not supplied

Efficacy of a support group programme for care-givers of demented patients in the community: a randomized controlled trial.

Dementia induces morbidity not only in the patients but also in the families taking care of them. Many studies described the impact of care-giving on physical and psychological health. Support groups were designed to alleviate the burden of care-givers. The objective of this study was to measure the efficacy of a support group programme for care-givers of demented patients in the community. Forty-one primary care-givers were randomly assigned to a study (n=23) or a control group (n=18). Subjects of the study group attended a structured programme of eight 2-h sessions. These weekly sessions consisted of information on the disease, role-playing on management of behavior problems, discussion on emotional impact of care-giving, and learning of stress management techniques. Subjects of the control group were referred to informal monthly meetings of the Alzheimer's Society. Subjects of both groups were evaluated at the entry (T1), after 8 weeks (T2) and after 8 months (T3). The outcome variables were the Burden Interview, the Revised Memory and Behavior Problems Checklist, the Brief Symptoms Inventory, the Alzheimer's Disease Knowledge Test and a questionnaire on health care utilization. Compared with the control group, subjects of the study group yielded only a significant increase in knowledge about the disease (p<0.0001) but no significant difference on the other outcome variables. It is concluded that this type of support group programme seems to have only a minimal impact on morbidity and on the burden of care-givers. These results are similar with two other studies examining the same issue.

Clinical Trial↗
PubMedDate not supplied

Isometric grip endurance of healthy elderly men and women.

Grip endurance is one of the important prerequisites for good performance of the upper extremity and hence it is important to evaluate it correctly. However, we know little about normal grip endurance, especially for elderly people. The main objective of this study was to examine the age-related changes in grip isometric endurance of healthy community-dwelling elderly people. Two-hundred and eighty-six subjects aged between 60 and 90, were randomly selected from the electoral list of the city of Sherbrooke, Quebec, Canada. Grip relative isometric endurance was evaluated using the Jamar dynamometer. Isometric grip endurance was estimated by the number of seconds a subject could sustain 50% of his/her maximal voluntary grip strength. Contrary to other upper extremity sensorimotor parameters, no grip isometric endurance difference was found with age, in spite of a slight tendency towards a decrease. The women tended to have better scores than the men and endurance of dominant hand is better than the non-dominant. The stability with age could be explained by muscle fiber composition modifications.

Journal Article↗
PubMedDate not supplied

A preventive program for community-dwelling elderly at risk of functional decline: a pilot study.

A program has been designed to assess and survey community-dwelling elderly over 75, identified at risk of functional decline by a postal questionnaire. The objectives were to verify the acceptability and the feasability of the program and to explore its impact, mainly on the functional status. A randomized controlled study took place in an urban community where 99 participants were drawn from those having responded positively to two or more of the six questions asked in the postal questionnaire, previously studied in Sherbrooke, in 1992. The program consisted in a home visit by a nurse who administered a standardized assessment battery on risk factors identified specifically for functional decline. When problems were identified, experimental subjects were referred to their general practitioner or to other health professionals for diagnosis and interventions. The control subjects received the usual health services. Both process and outcome measures were utilized in the study. The process measures allowed to know whether the program was acceptable or not to subjects and if it was feasible when using the existing health care services. The outcome measures included the number of eliminated risk factors, the functional autonomy level, the general well-being, the perceived state of health and the social support. The results showed that the program was feasible to implement and acceptable by the subjects and by health professionals. After 6 months, study subjects did not loose autonomy whereas the control ones significantly declined (P<0.001). If preventive programs could be effective in reducing the loss of autonomy, the use and cost of health care services could also be reduced and the other health and wellfare problems could be also prevented.

Journal Article↗
PubMedDate not supplied

Impact of elbow position on grip strength of elderly men.

Grip strength is frequently measured in rehabilitation settings in order to monitor patient progress. Many factors influence grip strength measurements, including body segment positions and particularly elbow position. The objective of this study was to compare grip strength measurements obtained with two different elbow positions: full extension and 90 degrees of flexion. Forty-nine healthy right-handed men aged 60 to 84 years were tested with a Jamar dynamometer. Results indicated that left grip strength was significantly higher when the elbow was flexed to 90 degrees compared with when it was fully extended. No statistical difference between the two elbow positions was found for the dominant hand.

Aged↗
PubMedDate not supplied

Normative data for grip strength of elderly men and women.

OBJECTIVES: Grip strength is an important prerequisite for good performance of the upper limb, hence it is important to evaluate it correctly. However, one of the main difficulties in evaluating the grip strength of elderly patients is the absence of valid norms. Therefore, the objective of this study was to develop normative data for maximum grip strength of persons aged 60 years and older. METHOD: The grip strength of 360 subjects aged 60 years and older, randomly recruited by age and gender strata, was evaluated with the Jamar dynamometer and the Martin vigorimeter according to the protocol of the American Society of Hand Therapists. RESULTS: Grip strength diminishes curvilinearly with age, and men are consistently stronger than women. The data are presented by the means, standard deviations, and range, and as predictive equations obtained by regression analysis. In addition to age and gender, hand circumference and body height proved to be the best indicators of grip strength for this population of elderly subjects. CONCLUSION: The random recruitment of subjects, the high participation rate in the study, and the comparability of the subjects who agreed to participate and those who refused give this study the high external validity that is essential to any norm study. The predictive equations will help occupational therapists to better estimate the expected grip strength of elderly patients than they could if using only age and gender.

Age Factors↗