Michael Brocaar - Academia.edu (original) (raw)
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Papers by Michael Brocaar
International Journal of Audiology, 1994
We tend not to think of music as noise but as a pleasant sound. Yet, played loud enough, music ca... more We tend not to think of music as noise but as a pleasant sound. Yet, played loud enough, music can become a threat to the human ear. The question arises whether professional musicians suffer from hearing losses caused by their playing of music. The hearing of students at the Rotterdam conservatory was studied; medical students served as a reference group. High percentages of audiometric noise dips (16%) and high-frequency losses (20%) were found in students of the conservatory, as well as a high percentage (72%) of extended high-frequency losses relative to the reference curves of Dreschler et al. Surprisingly, an equally large (and in the high-frequency region an even higher) percentage of hearing losses was found in the control group of medical students with the same median age. In sum, the exposure of conservatory students to the practice of music has as yet had no effect on their hearing.
International Journal of Audiology, 1984
The test-retest variability of a series of auditory functions has been investigated in a group of... more The test-retest variability of a series of auditory functions has been investigated in a group of severely hearing-impaired and deaf subjects (64 ears, median Fletcher index: 80 dB) and in a group of 10 controls with normal hearing. An adaptive forced-choice procedure was used for both groups. The functions were: tone audiogram, difference limen for intensity, difference limen for frequency, modulation transfer function and critical ratio. In spite of sometimes strongly deviating function values within the hearing-impaired group, the test-retest variability of the two groups was found to be of the same order of magnitude, except for the tone audiogram where the variability in the hearing-impaired group was twice that for the control group.
International Journal of Audiology, 1985
Speech reception functions (maximum discrimination score for phonemes, speech reception threshold... more Speech reception functions (maximum discrimination score for phonemes, speech reception threshold) and auditory functions (pure-tone audiogram, difference limens for frequency and intensity, temporal modulation transfer function, critical ratio and temporal integration) have been investigated in a group of severely hearing-impaired and deaf subjects (median Fletcher index: 80 dB), for different frequency regions (250, 1 000 and 2 000/4 000 Hz). The correlations between the different functions were calculated on the basis of characteristic numbers, derived from the originally measured functions, in the indicated frequency regions. The residual hearing capacities could be described best with two factors, one reflecting the distortion term in the speech reception threshold and the other representing the frequency discrimination for high-frequency tones. It was found that residual hearing capacities are present, at least up to a Fletcher index of 105 dB.
Clinical Otolaryngology, 1994
In a prospective study the effects on the voice of nandrolone decanoate super-imposed on cyclical... more In a prospective study the effects on the voice of nandrolone decanoate super-imposed on cyclical hormonal replacement therapy (HRT) given to post-menopausal women suffering from a severe form osteoporosis were compared with the effects of HRT alone. Comparing the experimental group with the control group, after one year of medication in the experimental group a higher percentage of patients had: a lower fundamental frequency during speech, a loss of high frequencies and an increase in voice instability and creakiness. The lowering of the frequencies and the increase of instability can be explained by histological changes in the vocal cords and by problems in the adaptation to these histological changes.
The Laryngoscope, Mar 5, 2016
To obtain actual status of age-related hearing loss in a general unscreened population of older D... more To obtain actual status of age-related hearing loss in a general unscreened population of older Dutch adults and to investigate whether the prevalence or degree has changed over time. To investigate the prevalence and degree of hearing loss, we conducted a large prospective cohort study of older adults between February 2011 and July 2015. Pure-tone air- and bone-conduction thresholds were measured for 4,743 participants. Results were compared to previous cohort studies. As expected, hearing loss increased with age. We found a correlation of R(2) = 0.317 for men and R(2) = 0.354 for women (right ears). A prevalence of hearing loss greater than 35 dB hearing level the average of 0.5/1/2/4 kHz in the better ear, was found in 33% of the male and almost 29% of the female participants aged 65 years and older. Compared with previous studies, men had less hearing loss at the frequencies of 2 kHz and above. Hearing thresholds in women were significantly higher at 4 and 8 kHz. The difference ...
Folia phoniatrica et logopaedica : official organ of the International Association of Logopedics and Phoniatrics (IALP), 2008
The purpose of this study was to investigate the interobserver variability and the test-retest va... more The purpose of this study was to investigate the interobserver variability and the test-retest variability of the Dysphonia Severity Index (DSI), a multiparametric instrument to assess voice quality. The DSI was measured in 30 nonsmoking volunteers without voice complaints or voice disorders by two speech pathologists. The subjects were measured on 3 different days, with an interval of 1 week. The difference in DSI between two observers (interobserver difference) was not significant. The intraclass correlation coefficient for the DSI was 0.79. The standard deviation of the difference between two duplicate measurements by different observers was 1.27. Differences in measurements between different observers were not significant. The intraclass correlation coefficient of the DSI was 0.79, which is to be considered good. Differences in DSI within one patient need to be larger than 2.49 to be significant.
Folia phoniatrica et logopaedica : official organ of the International Association of Logopedics and Phoniatrics (IALP), 2006
Attempts have been made to find objective parameters for assessing voice quality for many years. ... more Attempts have been made to find objective parameters for assessing voice quality for many years. Objective measurements such as the dysphonia severity index (DSI), using four parameters (highest frequency, lowest intensity, maximum phonation time and jitter), appear to correlate well with perceptual evaluation. The aim of this study was to investigate the influence, if any, of age and gender on the DSI. The DSI of 118 non-smoking adults (69 females, 49 males, age range 20-79 years) without voice complaints was measured. Age has a significant effect on the DSI and on its parameters highest frequency and lowest intensity (only in females). Gender has no effect on the DSI, although it has a significant effect on the parameters highest frequency and maximum phonation time. To be able to distinguish between the effects of (normal) ageing and a voice disorder, normative data of a wide age range are essential. As a result of this study normative DSI values for gender and age have been made...
International journal of pediatric otorhinolaryngology, 1995
Click-evoked otoacoustic emissions (cEOAEs) were repeatedly recorded in an operational sample of ... more Click-evoked otoacoustic emissions (cEOAEs) were repeatedly recorded in an operational sample of 144 very low birth weight (VLBW) infants. A subgroup of 22 was composed of all those babies in which at least 4 recordings were successfully done. The mean birth weight of this group was 1040 g, and the mean duration of assisted ventilation was 17 days. The OAE-recordings were done in the post conceptional age (PCA) range between 30 and 68 weeks. In relation to ear function screening it was shown that the EOAE was present in 95% of the ears at least once at any age, while it was present in all recordings in only 34%. From a longitudinal analysis of the recordings per infant it appeared that: (1) the OAE recorded was already present in one infant at the PCA of 29.4 weeks; (2) in most infants the level of the OAE varies strongly between recordings; (3) in each infant the OAE-level shows an increase with age, on average this growth amounts to 10 dB between the PCAs of 31 and 42 weeks; (4) t...
International Journal of Audiology, 1994
We tend not to think of music as noise but as a pleasant sound. Yet, played loud enough, music ca... more We tend not to think of music as noise but as a pleasant sound. Yet, played loud enough, music can become a threat to the human ear. The question arises whether professional musicians suffer from hearing losses caused by their playing of music. The hearing of students at the Rotterdam conservatory was studied; medical students served as a reference group. High percentages of audiometric noise dips (16%) and high-frequency losses (20%) were found in students of the conservatory, as well as a high percentage (72%) of extended high-frequency losses relative to the reference curves of Dreschler et al. Surprisingly, an equally large (and in the high-frequency region an even higher) percentage of hearing losses was found in the control group of medical students with the same median age. In sum, the exposure of conservatory students to the practice of music has as yet had no effect on their hearing.
International Journal of Audiology, 1984
The test-retest variability of a series of auditory functions has been investigated in a group of... more The test-retest variability of a series of auditory functions has been investigated in a group of severely hearing-impaired and deaf subjects (64 ears, median Fletcher index: 80 dB) and in a group of 10 controls with normal hearing. An adaptive forced-choice procedure was used for both groups. The functions were: tone audiogram, difference limen for intensity, difference limen for frequency, modulation transfer function and critical ratio. In spite of sometimes strongly deviating function values within the hearing-impaired group, the test-retest variability of the two groups was found to be of the same order of magnitude, except for the tone audiogram where the variability in the hearing-impaired group was twice that for the control group.
International Journal of Audiology, 1985
Speech reception functions (maximum discrimination score for phonemes, speech reception threshold... more Speech reception functions (maximum discrimination score for phonemes, speech reception threshold) and auditory functions (pure-tone audiogram, difference limens for frequency and intensity, temporal modulation transfer function, critical ratio and temporal integration) have been investigated in a group of severely hearing-impaired and deaf subjects (median Fletcher index: 80 dB), for different frequency regions (250, 1 000 and 2 000/4 000 Hz). The correlations between the different functions were calculated on the basis of characteristic numbers, derived from the originally measured functions, in the indicated frequency regions. The residual hearing capacities could be described best with two factors, one reflecting the distortion term in the speech reception threshold and the other representing the frequency discrimination for high-frequency tones. It was found that residual hearing capacities are present, at least up to a Fletcher index of 105 dB.
Clinical Otolaryngology, 1994
In a prospective study the effects on the voice of nandrolone decanoate super-imposed on cyclical... more In a prospective study the effects on the voice of nandrolone decanoate super-imposed on cyclical hormonal replacement therapy (HRT) given to post-menopausal women suffering from a severe form osteoporosis were compared with the effects of HRT alone. Comparing the experimental group with the control group, after one year of medication in the experimental group a higher percentage of patients had: a lower fundamental frequency during speech, a loss of high frequencies and an increase in voice instability and creakiness. The lowering of the frequencies and the increase of instability can be explained by histological changes in the vocal cords and by problems in the adaptation to these histological changes.
The Laryngoscope, Mar 5, 2016
To obtain actual status of age-related hearing loss in a general unscreened population of older D... more To obtain actual status of age-related hearing loss in a general unscreened population of older Dutch adults and to investigate whether the prevalence or degree has changed over time. To investigate the prevalence and degree of hearing loss, we conducted a large prospective cohort study of older adults between February 2011 and July 2015. Pure-tone air- and bone-conduction thresholds were measured for 4,743 participants. Results were compared to previous cohort studies. As expected, hearing loss increased with age. We found a correlation of R(2) = 0.317 for men and R(2) = 0.354 for women (right ears). A prevalence of hearing loss greater than 35 dB hearing level the average of 0.5/1/2/4 kHz in the better ear, was found in 33% of the male and almost 29% of the female participants aged 65 years and older. Compared with previous studies, men had less hearing loss at the frequencies of 2 kHz and above. Hearing thresholds in women were significantly higher at 4 and 8 kHz. The difference ...
Folia phoniatrica et logopaedica : official organ of the International Association of Logopedics and Phoniatrics (IALP), 2008
The purpose of this study was to investigate the interobserver variability and the test-retest va... more The purpose of this study was to investigate the interobserver variability and the test-retest variability of the Dysphonia Severity Index (DSI), a multiparametric instrument to assess voice quality. The DSI was measured in 30 nonsmoking volunteers without voice complaints or voice disorders by two speech pathologists. The subjects were measured on 3 different days, with an interval of 1 week. The difference in DSI between two observers (interobserver difference) was not significant. The intraclass correlation coefficient for the DSI was 0.79. The standard deviation of the difference between two duplicate measurements by different observers was 1.27. Differences in measurements between different observers were not significant. The intraclass correlation coefficient of the DSI was 0.79, which is to be considered good. Differences in DSI within one patient need to be larger than 2.49 to be significant.
Folia phoniatrica et logopaedica : official organ of the International Association of Logopedics and Phoniatrics (IALP), 2006
Attempts have been made to find objective parameters for assessing voice quality for many years. ... more Attempts have been made to find objective parameters for assessing voice quality for many years. Objective measurements such as the dysphonia severity index (DSI), using four parameters (highest frequency, lowest intensity, maximum phonation time and jitter), appear to correlate well with perceptual evaluation. The aim of this study was to investigate the influence, if any, of age and gender on the DSI. The DSI of 118 non-smoking adults (69 females, 49 males, age range 20-79 years) without voice complaints was measured. Age has a significant effect on the DSI and on its parameters highest frequency and lowest intensity (only in females). Gender has no effect on the DSI, although it has a significant effect on the parameters highest frequency and maximum phonation time. To be able to distinguish between the effects of (normal) ageing and a voice disorder, normative data of a wide age range are essential. As a result of this study normative DSI values for gender and age have been made...
International journal of pediatric otorhinolaryngology, 1995
Click-evoked otoacoustic emissions (cEOAEs) were repeatedly recorded in an operational sample of ... more Click-evoked otoacoustic emissions (cEOAEs) were repeatedly recorded in an operational sample of 144 very low birth weight (VLBW) infants. A subgroup of 22 was composed of all those babies in which at least 4 recordings were successfully done. The mean birth weight of this group was 1040 g, and the mean duration of assisted ventilation was 17 days. The OAE-recordings were done in the post conceptional age (PCA) range between 30 and 68 weeks. In relation to ear function screening it was shown that the EOAE was present in 95% of the ears at least once at any age, while it was present in all recordings in only 34%. From a longitudinal analysis of the recordings per infant it appeared that: (1) the OAE recorded was already present in one infant at the PCA of 29.4 weeks; (2) in most infants the level of the OAE varies strongly between recordings; (3) in each infant the OAE-level shows an increase with age, on average this growth amounts to 10 dB between the PCAs of 31 and 42 weeks; (4) t...