Development and the role of internal noise in detection and discrimination thresholds with narrow band stimuli.
(73/570)
The experiments reported here examine the role of internal noise in the detection of a tone in narrow band noise and intensity discrimination for narrow band stimuli in school-aged children as compared to adults. Experiment 1 used 20-Hz wide bands of Gaussian and low-fluctuation noise centered at 500 Hz to assess the role of stimulus fluctuation in detection of a 500-Hz pure tone. Additional conditions tested whether performance was based on level and/or level-independent cues. Children's thresholds were elevated with respect to adults, and whereas adults benefited from the reduced fluctuation of low-fluctuation noise, children did not. Results from both groups were consistent with the use of a level cue. Experiment 2 estimated intensity increment thresholds for a narrow band Gaussian noise or a pure tone, either with or without a presentation-by-presentation level rove, an additional source of level variability. Stimulus variability was found to have a larger effect on performance of adults as compared to children, a rather counterintuitive finding if one thinks of children as more prone to informational masking introduced by stimulus variability. Both tone-in-noise and intensity discrimination data were consistent with the hypothesis that children's performance is limited by greater levels of internal noise. (+info)
Hypertension as a factor associated with hearing loss.
(74/570)
AIM: To identify likely association between blood hypertension and hearing loss. DESIGN: A non-paired case-control study. SETTING: Institutional work carried out at Universidade Norte do Parana, in South Brazil. MATERIAL AND METHOD: 154 cases and 154 controls, both genders, aged 45 to 64, included in the research after sample estimation. METHODOLOGY: Hypertension was verified through blood pressure readings and by a systematized questionnaire about hypertension and the use of medication for blood pressure. Hearing was assessed through tonal threshold audiometrics and audiologic anamneses. Non-conditional logistic regression was used in order to control likely confusion or modification of effect of other variables on interest associations. RESULTS: There is a significant association between blood hypertension and hearing loss. Hearing loss in the population under study suggests that hypertension is an accelerating factor of degeneration of the hearing apparatus due to aging. CONCLUSIONS: The results in this research, through evidence of association between blood hypertension and hearing loss, can allow for an integrated work of cardiologists, nephrologists, otorhinolaryngologists, audiologists and other health professionals concerned with alterations caused by blood hypertension. (+info)
High-frequency audiometry in young and older adults when conventional audiometry is normal.
(75/570)
High-frequency audiometry can detect early changes in auditory sensitivity resulting from processes such as aging. Nonetheless its use is still limited, and additional studies are required to establish its use, particularly among older adults. AIM: To compare pure tone thresholds for frequencies from 250 Hz to 16 kHz in young and older adults, with or without audiologic complaints. METHOD: Pure tone sensitivity to 250 Hz to 16 kHz was assessed with an AC-40 audiometer in 64 adults, evenly distributed in young (25 to 35 years-old) and older (45 to 55 years-old) adults of both sexes. This is a cross-sectional study. RESULTS: Although all participants presented normal audiometry in frequencies from 250 Hz to 8 kHz, according to clinical parameters, older adults had significantly higher thresholds compared to young adults, according to statistical parameters, with greater significance in higher frequencies (8 to 16 kHz). Presence or absence of clinical complaints did not distinguish thresholds. CONCLUSIONS: The process of auditory aging, including loss of sensitivity to higher frequencies, can be detected at earlier ages than those usually investigated. High frequency audiometry is an important instrument to distinguish auditory sensitivity in young and older adults, even for those considered as audiologically normal. (+info)
Identifying dead regions in the cochlea through the TEN test.
(76/570)
An audiogram is not sufficient to indicate cochlear dead regions. AIM: To investigate cochlear dead regions in sensorineural hearing loss subjects using the TEN test. SITE: CEDALVI/ HRAC-USP-Bauru/Sao Paulo/Brazil, August 2003 to February 2004. STUDY DESIGN: A contemporary cross-sectional cohort study. MATERIAL AND METHODS: The TEN test was applied in three groups: G1(5 women with pure-tone thresholds within normal limits); G2(4 women and 5 men with moderate sensorineural flat hearing loss); G3(19 women and 24 men with mild to severe sloping sensorineural hearing loss). RESULTS: In the G1 group the TEN value required to eliminate the test tone was, on average, close to the absolute threshold for all frequencies. No dead regions were found in the ears tested in group G2. 76 ears were tested in group G3, and six showed no evidence of dead regions in the cochlea. CONCLUSIONS: The TEN test was an effective test to indicate a dead region in the cochlea of subjects with sloping sensorineural hearing loss. There is evidence that pure-tone detection is different for subjects with high frequency sensorineural hearing loss and flat hearing loss; we observed a significant difference between the masked threshold and the absolute threshold only in sloping hearing loss and not for flat hearing loss. (+info)
Phone positioning influence in high-frequency audiometry.
(77/570)
Research considers high frequency tonal audiometry as a tool for the early diagnosis of auditory alterations derived from etiological agents. AIM: to investigate possible differences in high frequency audiometry of individuals with normal hearing, based on the person who places the earphone. PATIENTS AND METHOD: clinical and experimental study with 55 undergraduate students from a country side branch of the Sao Paulo State University, with normal hearing, underwent two tests each; for the first, the evaluator positioned the earphone on the participant; for the second one, the participant did it by him/herself. An AC40 audiometer calibrated to emit pure tone was used in the frequencies of 10, 12.5, and 16 kHz. RESULTS: The kappa(k) coefficient statistical analysis was used to verify the agreement between the two ways of earphone positioning of earphone, bearing a [FORMULA: SEE TEXT]0.70 kappa value as a criterion. Results attained for both ears were below this criterion, with k average of 0.50. DISCUSSION: results indicate a risk of compromising the exam reliability when the patient him/herself adjusts phone to his/her own ear. CONCLUSION: when performing audiometric assessment, this variable must be considered in order to attain reliable results. (+info)
Schwannoma of the external auditory canal: a case report.
(78/570)
BACKGROUND: Schwannomas are uncommon benign tumors of the external auditory canal. The clinical features, the differential diagnosis, and the surgical treatment of these lesions are discussed. CASE PRESENTATION: A 51-year-old patient presented with a mass obliterating the external auditory meatus. Excisional biopsy was performed. Diagnosis was reported to be schwannoma by histopathologic examination. CONCLUSION: Schwannoma, rarely seen in the external auditory canal, can be managed by a precise excision of the tumor via transmeatal approach. (+info)
Audiological and electrophysiological evaluation of children with acquired immunodeficiency syndrome (AIDS).
(79/570)
We examined the peripheral auditory system and the auditory brainstem pathway of children with Acquired Immunodeficiency Syndrome (AIDS). One hundred and one children, 51 with AIDS diagnosis and 50 normal children were evaluated. Audiological assessment included immittance measures, pure tone and speech audiometry and auditory brainstem response (ABR). The children with AIDS more frequently had abnormal results than did their matched controls, presenting either peripheral or auditory brainstem impairment. We suggest that AIDS be considered a risk factor for peripheral and/or auditory brainstem disorders. Further research should be carried out to investigate the auditory effects of HIV infection along the auditory pathway. (+info)
Individual differences in the masking level difference with a narrowband masker at 500 or 2000 Hz.
(80/570)
The masking level difference (MLD) for a narrowband noise masker is associated with marked individual differences. This pair of studies examines factors that might account for these individual differences. Experiment 1 estimated the MLD for a 50 Hz wide band of masking noise centered at 500 or 2000 Hz, gated on for 400 ms. Tonal signals were either brief (15 ms) or long (200 ms), and brief signals were coincident with either a dip or peak in the masker envelope. Experiment 2 estimated the MLD for both signal and masker consisting of a 50 Hz wide bandpass noise centered on 500 Hz. Signals were generated to provide only interaural phase cues, only interaural level cues, or both. The pattern of individual differences was dominated by variability in NoSpi thresholds, and NoSpi thresholds were highly correlated across all conditions. Results suggest that the individual differences observed in Experiment 1 were not primarily driven by differences in the use of binaural fine structure cues or in binaural temporal resolution. The range of thresholds obtained for a brief NoSpi tonal signal at 500 Hz was consistent with a model based on normalized interaural correlation. This model was not consistent for analogous conditions at 2000 Hz. (+info)