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Biomedical subjects

T S Kapteyn

Publications and source records attributed to T S Kapteyn.

At least 19 recordsLinked to original sources
PubMed2001

A proposal for a model to calculate hearing disability.

The present paper presents an alternative method to calculate hearing disability. As opposed to existing models to calculate hearing disability, the present method is not just based on the pure-tone audiogram. Hearing activities playing an important role in daily listening are taken into account: detection of sounds, distinction of sounds, intelligibility in quiet and in noise, auditory localization. Psycho-acoustical tests to measure each of these activities are described. Test scores are used to calculate overall hearing disability. A comparison is made between the present model and the method of the American Medical Association (AMA). Calculations are based on theoretical cases only. Further study has to be undertaken to verify the calculations by examining the scores of real cases to improve the validity and internal consistency of the present model.

Audiometry, Pure-Tone↗
PubMed1998

[Rehabilitation possibilities for hearing-impaired subjects].

Hearing impairment is a symptom, not a diagnosis. A number of types of hearing impairment can be distinguished. The self-reported hearing problems cluster around six hearing factors, the most important of which are speech understanding in noise and localisation of a sound source. For these capabilities equivalent functioning of both ears is important. The general practitioner can determine diagnosis and severity of the impairment using rather simple tools. When the cause of the impairment cannot be reduced in a proper way an adaptation of the sound to the impaired ear will be indicated. This can be arranged by either an ENT specialist or a centre for audiology. The selection of a proper hearing aid requires expertise and particular attention for the complaints. It is of the utmost importance that the hearing-impaired person can try out the effects of the hearing aid in daily circumstances for some weeks. If the patient, members of the family or the prescriber are not satisfied with the results, supplementary help is required, for example training in communication skills or special devices.

Adaptation, Physiological↗
PubMed1997

The effects of involvement of the general practitioner and guidance of the hearing impaired on hearing-aid use.

A number of international and national publications report that hearing aids are sometimes under used. In this paper, results are reported of a project to increase the effective use of hearing aids. The first intervention was aimed at a more effective exchange of information between the general practitioner (GP) and the ENT specialist. This was achieved by the introduction of a structured referral form. In addition, a simple hearing aid was placed at the GP's disposal for demonstration purposes. As a second, independent intervention, 50% of the patients were visited at home by a trained volunteer. A measure of effective use that combines the effectiveness and actual use had been developed. After the first intervention the non-effective use of hearing aids decreased from 38% to 30%, this being just below statistical significance (p = 0.12). The protocol approach by the GP in combination with the demonstration hearing aid proved to be especially useful. Patients with a counselling visit at home had a significantly lower level of non-effective use (27% versus 37%; p < 0.05) than patients who had not been visited.

Age Factors↗
PubMed1994

Effect of time-scale modification of speech on the speech recognition threshold in noise for hearing-impaired and language-impaired children.

In this study, the effect of time-compression and expansion of speech on speech perception in noise was measured for a group of hearing-impaired and a group of language-impaired children relative to control groups of normal children and normal adults. The children's ages ranged from 9 to 12 years. For all time-scale modified conditions, both hearing-impaired and language-impaired children had significantly higher speech recognition thresholds in noise (SRTN) than their normal peers, who performed almost equally well as the adult control group. Time-expansion was shown to have a negligible effect on SRTN for all groups when compared to the control condition, i.e. 0% time-compression. The difference in SRTN between the control and the impaired groups was, in general, not significantly altered by the degree of time-compression or expansion of speech, although a clear trend towards greater differences for increasing time-compression was observed. Five tests of auditory discrimination and auditory memory were also administered to both groups of impaired children. In a step-wise multiple regression procedure, 94% of variation in SRTN in the control condition could be explained by the score on the ADIT C (type Wepman; discrimination task) and the maximum speech recognition score for monosyllables in quiet.

Acoustic Stimulation↗
PubMed1992

Technical possibilities in the school situation for the education of hearing-impaired children.

For hearing-impaired children, the main problem in the classroom is the signal-to-noise ratio. To improve the signal-to-noise ratio, several class systems have been developed, three of which have been investigated in this study. The systems are shown to be equivalent in a situation without a channel for pupil response. Application of such pupil response channels will decrease the improvement in signal-to-noise ratio brought about by the class system. It is argued that the choice among several combinations of class system and pupil response channel is governed by the primary goal of education and how this goal is to be achieved.

Adolescent↗
PubMed1985

Verification of the air-bone gap using cancellation and evoked responses.

Using the cancellation method as well as evoked responses, we investigated their application in the estimation of the air-bone gap in patients undergoing operation on middle ear structures. The cancellation method had a closer relationship with pure-tone audiometry than evoked responses in predicting the air-bone gap. This was caused by recruitment, by which the cancellation method was not affected. The results of brainstem-evoked responses to bone and air conduction signals showed therefore an underestimation in the prediction of the air-bone gap. Combining the cancellation method with evoked responses elicited to air conduction signals permitted the estimation of the cochlear reserve without the need of threshold measurement by bone conduction.

Adult↗
PubMed1984

Phase relationship between bone and air conducted impulse signals in the human head.

Using the cancellation method we investigated the phase relationship as well as the amplitude ratio between impulse signals transmitted simultaneously via both bone and air conduction channels. The psychophysical findings indicated a phase difference corresponding to a time delay of about 0.9 ms by which the air input led the bone input in the case of frontal bone stimulation. Changing the polarity of the bone conduction signal a maximum in the loudness sensation was found just in the same phase difference. The psychophysical findings, predicted mathematically, were verified with brainstem evoked potentials elicited to similar signals. Preliminary results showed that the time lag observed relied on the location of the bone vibrator on the head and furthermore on the frequency used. This suggests different transmissions of vibratory energy reaching the inner ear along the skull.

Bone Conduction↗
PubMed1983

Comparison of the latencies between bone and air conduction in the auditory brain stem evoked potential.

Brain stem auditory evoked potentials obtained by air and bone conduction were investigated in 22 subjects. The necessity for a carefully selected stimulus being presented to the headphone and the bone vibrator is discussed. Latency values of both responses are presented for wave V. Bone conduction showed latencies which were longer than those obtained by air conduction (about 0.9 msec). Possible mechanisms for this delay are discussed.

Audiometry↗
PubMed1983

Effect of contralateral and ipsilateral masking of acoustic stimulation on the latencies of auditory evoked potentials from cochlea and brain stem.

Masking techniques were applied to a group of 10 subjects with normal hearing, to investigate the influence of masking on the latencies of brain stem auditory evoked potentials. The levels of sufficient masking and overmasking were determined. Central masking, as established in a psychophysiological manner, cannot be clearly demonstrated by auditory brain stem evoked potentials. When masking the untested ear, the alterations in the response are small and this can be ignored in clinical practice if masking of the untested ear is necessary.

Acoustic Stimulation↗
PubMed1982

[Rehabilitation possibilities in presbycusis].

Although several types of hearing loss in aged people can be distinguished, the word presbyacusis has grown to common use. It is not primarily the decrease of sensitivity for sounds, but rather the decrease of the ability for discrimination and the increase of being troubled by noisy circumstances, that impair understanding of speech. Conversation with aged people have to be practised slowly and in a well pronounced way in favourite circumstances for listening. The hearing impairment in aged people can grow to a problem, especially by the social circumstances, so rehabilitation may not be restricted to the aged themselves. A good insight in the remaining abilities of the hearing is the base for the prescription and the acceptance of a hearing aid. In this the fitting of the earmold and the adjustment of the output level-limiter are the most important factors. The participation in the verbal communication can become more easy and relaxed by a clever usage of the aid's abilities, but the partners in the conversation have to understand the difficulties and to be cooperative.

Aged↗
PubMed1980

The cancellation method for an accurate determination of an air-bone gap.

For a reliable detection of the bone conduction threshold blocking of the contralateral ear can be necessary but then the noise will affect the threshold in the test ear. To resolve this problem the cancellation method is used. The equalization of air and bone conduction sound level in the inner ear is very accurate, the relation between the intensities has been proved to be linear and independent of noise at the contralateral ear. An application for calibration of the bone conduction vibrator to the head phone is discussed. The benefit of the method for measuring an air-bone gap in an accurate way in patients suffering bilaterally from a severe conductive hearing loss is shown.

Auditory Threshold↗
PubMed1979

Height vertigo and human posture.

A theory is presented supporting a geometrical explanation for physiological height vertigo being a distance vertigo through visual destabilization of postural balance when the distance between the eyes and visible stationary contrasts becomes critically large. Physiological and posturographic data obtained under natural height vertigo conditions are consistent with this hypothesis.

Humans↗