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L Collet

Publications and source records attributed to L Collet.

At least 163 records · Page 9Linked to original sources
PubMed1987

Effect of stimulus intensity variation on brain-stem auditory evoked potentials: comparison between neonates and adults.

Brain auditory evoked potentials (BAEPs) were recorded from 40 adult subjects and 40 neonates at 80 and 60 dB (nHL) to compare the effects of stimulus intensity variation on waves I, III and V and on intervals I-III, III-V and I-V. The results show that the changes in latency for wave, I, I-III and I-V intervals are significantly greater in neonates than in adults. So the effects of stimulus intensity variation on BAEPs are different in neonates and in adults and a major effect is in the peripheral auditory mechanism.

Acoustic Stimulation↗
PubMed1987

Brainstem auditory evoked responses alteration in twin neonates.

The authors obtained BAER recordings for 20 premature twins and 20 premature non-twins. The two groups were comparable as to conceptional age (36-37 weeks), gestational age, chronological age, birthweight, sex ratio and head size. The results showed a prolongation of the central conduction time (I-V interval) in the premature twins. This may be due to the intra-uterine growth retardation of twins.

Birth Weight↗
PubMed1987

Endorectal cerebral evoked potentials in human.

Reproducible cerebral evoked responses have been recorded from the vertex in two men and one woman to endorectal electrical stimulation. The first component had a 36 ms latency for the woman, and an average latency of 90 ms for the men.

Adult↗
PubMed1986

An auditory psychophysical correlate of depression.

In this study, we examine the possible relation between depression and a diminution of subjective pleasure experienced during sensory stimulation. A subjective evaluation of 5 pure sounds presented at random 5 times to each subject was carried out with 10 depressive subjects, 10 non-depressive psychiatric subjects, and 10 non-depressive subjects, the three groups being matched for sex and age. In depressed subjects, the results showed no reduction in the number of experiences of subjective pleasure but a significant reduction in the repeatability of subjective pleasure associated with a given sound. These modifications seems to be specific to depression since psychiatric patients receiving neurotropic drug behave as control subjects. On the other hand, no such significant difference is found in the repeatability of a subjectively unpleasant experience. Finally, when all subjects are considered on the same continuum of depression, a significant negative correlation is found (P less than 0.01) between the degree of depression as measured by the Beck Depression Inventory and the number of sounds for which repeatability of subjective pleasure is obtained over 5 trials. Our results extend into the sensory realm the reduction in the repeatability of subjective pleasure already established for depressed subjects in the social realm; this is discussed in terms of positive reinforcement reduction associated with depression.

Acoustic Stimulation↗
PubMed1986

GSR feedback and Schultz relaxation in tension headaches: a comparative study.

A comparative study of the use of GSR feedback (n = 16) and Schultz relaxation (n = 15) with patients presenting tension headaches showed that there was no significant improvement in the group treated by relaxation at the end of the treatment whereas the group treated by GSR feedback showed significant improvements with respect to frequency and intensity of headaches and to anxiety as measured by subjects' self-evaluation (P less than 0.05). Intergroup comparison demonstrated a greater improvement in headache intensity for the GSR feedback group than for the relaxation group (P less than 0.05) at the post-treatment stage. Likewise, the percentage of patients showing at least 50% improvement as to headache frequency was significantly higher (P less than 0.05) in the GSR feedback than in the relaxation group. High pre-treatment EMG and high pre-treatment weekly pain level indicate a good prognosis of improvement with respect to post-treatment headache frequency and intensity respectively in the case of the GSR feedback group. We found no prognostic factor for post-treatment clinical improvement in the relaxation group.

Adult↗
PubMed1986

Auditory field reduction in human following head trauma.

We measured the tonal auditory threshold for 500, 2000 and 4000 Hz, and made BAER recordings for both ears with unfiltered 125 dB SPL clicks, with 40 subjects between 18 and 23 years of age, 20 subjects having suffered minor cranial trauma during the preceding 48 hours and 20 being control subjects matched for age and sex. Compared to the control group, trauma patients showed a significantly higher auditory threshold: 19 dB SPL at 500 Hz, 9 dB SPL at 2000 and 4000 Hz. This threshold rise was bilateral. The head trauma patients showed, on average, one significantly earlier BAER wave I than did controls. This alteration was likewise bilateral. The latencies of waves II, III and V, the I-III, III-V, and I-V intervals, and the interaural wave latency and interval differences are comparable for trauma patients and control subjects. One to eight months after cranial trauma, 7 subjects manifested one sign of the subjective cranial trauma syndrome. Auditory threshold and BAER wave I earliness were not any greater for these subjects. Trauma patients seemed to show a reduction of the auditory field. They were hypersensitive to high stimulus intensities (shortening of BAER wave I) and less sensitive to low intensities (rise in tonal auditory threshold). This auditory alteration was bilateral. It can thus be thought that the trauma acts on the central nervous system to affect the operation of the cochlea via efferent pathways.

Adolescent↗
PubMed1983

The treatment of writer's cramp with multimodal behaviour therapy and biofeedback: a study of 15 cases.

Of 15 patients with writer's cramp (4 females, 11 males, mean age 36, range 23-50, mean duration 3.6 years), 13 entered a behavioural treatment. Nine received a multimodal treatment, and four EMG feedback alone. Four patients dropped out during the treatment phase. Nine patients were considered as improved at a follow-up between 1 and 9 months. A stress-coping model is put forward to account for the therapeutic effectiveness, and to explain the drop-outs. Writer's cramp seems to be related to stressful situations at work. The existence of personality and biological factors remains to be demonstrated.

Adult↗
PubMed1981

[Circannual rhythm of schizophrenic births (author's transl)].

Seven studies (in Switzerland, USA, United Kingdom, Canada, Japan, Sweden, Denmark) have shown the probable existence of a circannual rhythm of schizophrenic birth with a peak in winter. Three hypothesis try to explain this fact: - a constitutional injure; - a different circannual rhythm in sexual activity of schizophrenic parents; - a chronobiological perturbation.

Birth Rate↗
PubMedDate not supplied

Evoked and spontaneous otoacoustic emissions. A comparison of neonates and adults.

Evoked otoacoustic emissions (EOAEs) and spontaneous otoacoustic emissions (SOAEs) were compared between neonates and adults. Several differences were seen for EOAEs: (i) the occurrence of EOAEs was significantly greater in adults than in neonates, and in neonates it increased with extra-uterine age; (ii) the high frequency EOAE intensity was greater in neonates than in adults; (iii) the EOAE intensity was significantly greater in neonates than in adults. No age-related differences for SOAEs were found: (i) age was not significantly related to the presence/absence of SOAEs in neonates or adults; (ii) the occurrence of SOAEs was, however, significantly greater in females than in males in both neonates and adults.

Acoustic Stimulation↗
PubMedDate not supplied

Maturation and effect of stimulus rate on brainstem auditory evoked potentials.

Brainstem auditory evoked potentials (BAEPs) at three stimulus rates (20, 41.3 and 61.3 c/s) were recorded in 104 normal preterm infants, distributed in four age groups between 32 and 39 weeks (conceptional age), and in 20 normal adults. The latency shifts between 61.3 c/s and 20 c/s, and between 41.3 c/s and 20 c/s, were calculated for each wave, and studied as a function of age. A significant effect of conceptional age was shown on the '61.3-20 c/s' and the '41.3-20 c/s' wave V latency shifts, and a significant difference between adults and newborns was noted for the wave V and wave III latency shifts. No significant difference was obtained for the wave I latency shifts. This suggests that the changes of auditory adaptation with maturation may be predominantly at a central level, i.e. on central synapses.

Acoustic Stimulation↗
PubMedDate not supplied

Effect of sleep stages on transiently evoked oto-acoustic emissions in infants.

Transiently evoked oto-acoustic emissions (TEOAEs) are generated by active contractions of the outer hair cells (OHC) of the organ of Corti. TEOAE are inhibited by the medial efferent olivocochlear system which originates in the brainstem and innervates the OHC. TEOAEs are a rapid non-invasive objective method of auditory screening in infants. Because in infants sleep represents 75% of their time, it was of interest to determine whether sleep stages which are induced in the brainstem could concomitantly affect TEOAEs. Repeated TEOAE recordings during polygraphic recordings of sleep stages were made on seven, 6-week-old infants. Results showed that: (i) TEOAE spectrum frequency components remained stable over sleep stages; (ii) TEOAE amplitude tended to increase during recording sessions; (iii) sleep stages (quiet, active and indeterminate sleep) did not affect TEOAE amplitude. This pilot study reveals that sleep mechanisms seem to have no effect on active OHC micromechanical properties. Therefore, in auditory screening, TEOAEs may serve to study active cochlear mechanisms in infants even during sleep which is the better time to perform recordings because of the quietness required.

Electrocardiography↗
PubMedDate not supplied

Otoacoustic emissions and brainstem auditory evoked potentials in children with neurological afflictions.

Findings are reported for evoked otoacoustic emissions (EOAEs) recorded from 22 children with neurological afflictions, whose brainstem auditory evoked potentials (BAEPs) were pathological on at least one side (41 ears explored). Our results confirmed that EOAEs are always present in children and infants having normal BAEPs. Absence of EOAE (n = 22) was almost always related to middle ear or cochlear damage with BAEPs indicating diagnoses, respectively, of transmission damage (n = 7) or endocochlear damage (n = 16). Conversely, for BAEP diagnoses of retrocochlear damage (n = 12), EOAEs were always present. EOAEs associated with BAEPs, therefore, appear to offer a well-adapted technique for precise etiological diagnosis of childhood hearing loss. When no wave is identifiable by BAEP recording, EOAE presence indicates retrocochlear damage.

Child↗
PubMedDate not supplied

Mutation in the zonadhesin-like domain of alpha-tectorin associated with autosomal dominant non-syndromic hearing loss.

A gene responsible for autosomal dominant non-syndromic hearing impairment in two families (DFNA8 and DFNA12) has recently been identified as TECTA encoding alpha-tectorin, a major component of the tectorial membrane. In these families, missense mutations within the zona pellucida domain of alpha-tectorin were associated with stable severe mid-frequency hearing loss. The present study reports linkage to DFNA12 in a new family with autosomal dominant high frequency hearing loss progressing from mild to moderate severity. The candidate region refined to 3.8 cM still contained the TECTA gene. A missense mutation (C1619S) was identified in the zonadhesin-like domain. This mutation abolishes the first of the vicinal cysteines (1619Cys-Gly-Leu- 1622Cys) present in the D4 von Willebrand factor (vWf) type D repeat. These results further support the involvement of TECTA mutations in autosomal dominant hearing impairment, and suggest that vicinal cysteines are involved in tectorial membrane matrix assembly.

Extracellular Matrix Proteins↗