Effects of Secondhand Smoke Exposure and Noise Exposure on Tinnitus Occurrence in College Students and Adolescents.

BACKGROUND: Recent research indicated that young adults and adolescents reported tinnitus in higher numbers than previously. Thus, it is important to fully investigate risk factors for tinnitus in adolescents and young adults. PURPOSE: The current study examined the influence of two environmental risk factors, secondhand smoke (SHS) exposure and noise exposure on tinnitus occurrence as self-reported by U.S. adolescents and young adults. RESEARCH DESIGN: A nonexperimental, cross-sectional design was used for this survey study. STUDY SAMPLE: Of 265 surveys received, 43 were excluded due to ineligibility. The remaining 222 surveys constituted the study sample. Participant respondents included 80 high school students (ages 14-17) and 142 college students (ages 18-30). The sample was primarily female (n = 160). DATA COLLECTION AND ANALYSIS: Three (3) yes/no survey questions regarding SHS exposure, noise exposure, and tinnitus occurrence were analyzed. Statistical analyses included logistic regression, chi-square follow-up tests, and Pearson bivariate correlation analysis. RESULTS: Results revealed that 40% of young adults and adolescents surveyed reported that they experienced tinnitus. Regression analysis revealed significant main effects for noise (p = 0.004), gender (p = 0.017), and the interaction of SHS and noise (p = 0.001). There was no main effect of SHS exposure nor age on tinnitus occurrence. Follow-up chi-square analysis conducted to probe the gender effect revealed that females (45.1%) were more likely to experience tinnitus than males (27.7%). Chi-square testing to examine the significant interaction effect revealed statistical significance (p = 0.001) for individuals with reported noise exposure but not for individuals without noise exposure. In the noise-exposed group, individuals who also reported SHS exposure had a lower occurrence of tinnitus (23.6%). In contrast, the noise-exposed individuals without SHS exposure had a higher prevalence of tinnitus (57.9%). An additional chi-square follow-up analysis to examine the main effect of noise revealed no significance (p = 0.199). However, there was a significant (p < 0.01) negative correlation (r = -0.244) of noise exposure with age. CONCLUSION: The current study results suggest there is a higher than expected report of tinnitus incidence in adolescents and young adults. The relationship between tinnitus occurrence and a combined exposure to noise and secondhand smoke revealed a unique effect in adolescents and young adults.

Effects of Secondhand Smoke Exposure on Hearing and Auditory Evoked Potentials, ABR and AMLR in Young Adults.

BACKGROUND: Population health is impacted by environmental secondhand smoke (SHS) exposure. Although the negative health effects of SHS exposure include respiratory problems in children (nonsmokers) as seen in cigarette smokers, other health impacts such as sensory function are not assumed to be the same for both passive nonsmokers and smokers. However, hearing loss was recently reported in adolescents and aging adults with SHS exposure, suggesting that SHS might impact auditory function similarly to cigarette smoking. Specific effects of SHS exposure on the central auditory system have not been fully described. PURPOSE: To measure auditory function via pure-tone audiometry and evoked potentials in young nonsmoking adults aged 18-23 yr who reported exposure to environmental SHS. RESEARCH DESIGN: Participants were selected for the SHS-exposed (SHS-E) group first, followed by age and gender matched individuals for the SHS-unexposed (SHS-U) group. Self-reported nonsmoker status was confirmed by biochemical analysis of urine for cotinine level. STUDY SAMPLE: Potential participants (N = 208) completed a questionnaire about health, smoking history, SHS exposure, and hearing ability. Individuals with any neurological conditions, alcohol/drug dependencies, excessive noise exposure, using certain medications, or current smokers were excluded. Twenty-two nonsmokers in excellent health consented to participate. Participants in the SHS-E group reported SHS exposure in home, work, or social settings for an extensive time period. Participants in the SHS-U group did not live with smokers and reported no SHS exposure, medication use, tinnitus, or any chemical exposures. Statistical analysis was conducted on data from 20 participants, 10 per group with a mean age of 20 yr. DATA COLLECTION AND ANALYSIS: Participants underwent auditory procedures in one session in an IAC sound-treated room, including otoscopy, tympanometry, pure-tone threshold evaluation, auditory brainstem response per ear, and a three-channel auditory middle latency response in the right ear. The primary study outcomes were hearing thresholds measured (dB HL) at five frequencies, and evoked potential wave latencies (I, III, V, Na, Pa, Nb, Pb) and amplitudes (V-I, Na-Pa, Pa-Nb, Nb-Pb). It was hypothesized that SHS-exposed individuals would have poorer hearing sensitivity (threshold >25 dB HL) and abnormal central auditory function (longer latencies; smaller amplitudes) based on evoked potentials. Statistical analyses focused on identification of group differences in hearing and central auditory function. RESULTS: All participants had normal hearing sensitivity (thresholds ≤25 dB HL) with no significant group differences. The V/I amplitude ratio in the right ear was significantly decreased in SHS-exposed individuals (p < 0.05). Auditory brainstem response latencies were not significantly different between participant groups or ears. Wave Pb latency was significantly increased in SHS-exposed individuals (p < 0.01). Auditory middle latency response relative amplitudes were significantly different from each other at every electrode site (Cz, Fz, C4) but not between groups. Overall, the Na-Pa complex was highest in amplitude at all three electrode sites. CONCLUSIONS: This preliminary study indicated toxic effects of SHS exposure by evoked potentials with decreased V/I amplitude ratio and longer (delayed) Pb latency in young adults. Further studies should corroborate these findings to facilitate clinical recommendations.

Digit speech recognition threshold (SRT) in children with normal hearing ages 5-8 years.

PURPOSE: The purpose of this study was to compare digit stimuli to popular spondees when measuring speech recognition threshold (SRT) in children with normal hearing and to determine the influence of increment size using a descending method (ASHA, 1988). METHOD: SRT was measured with paired digit stimuli (D-SRT) and pediatric word stimuli (W-SRT) using 2 step sizes (5 dB, 2 dB) in 30 typically developing children with normal hearing ages 5;0 (years;months) to 8;11. Pure-tone and SRT tests were administered in both ears. The D-SRT and W-SRT were compared to pure-tone average (PTA) thresholds per ear. RESULTS: Analysis of variance revealed a significant interaction of test and step size: PTA was significantly lower when measured with 2-dB than with 5-dB increment; however, step size yielded no differences in D-SRT and W-SRT. Right ear thresholds across tests were significantly lower than left ear. Pearson correlations were significant for all tests except two; D-SRT was highly correlated to W-SRT (r = .49-.72) in both ears. Regression analyses for both ears and step sizes revealed that prediction of the hearing threshold for speech from PTA was equally accurate for SRT measured with digit pairs or popular pediatric spondee stimuli. CONCLUSION: Digit pairs are an appropriate alternative stimulus for SRT measurement in children with normal hearing. Future diagnostic audiology implications, including application for other pediatric populations, are discussed.

Auditory middle latency responses in chronic smokers compared to nonsmokers: differential effects of stimulus and age.

PURPOSE: Effects of clicks and tonebursts on early and late auditory middle latency response (AMLR) components were evaluated in young and older cigarette smokers and nonsmokers. METHOD: Participants ( n = 49) were categorized by smoking and age into 4 groups: (a) older smokers, (b) older nonsmokers, (c) young smokers, and (d) young nonsmokers. Monaural, 2-channel AMLRs were acquired from Fz and Cz electrodes with 3 stimuli (clicks, 500 Hz, and 3000 Hz). RESULTS: Group differences included significantly higher V-Na amplitude in young adults and shorter Pb latency in older nonsmokers. Young smokers had a significantly higher Nb-Pb amplitude and shorter Nb latency than other groups. Toneburst stimuli yielded significantly longer V, Na, and Pa latencies compared to clicks. Pb latency was shorter at Fz than at Cz. Relative amplitudes were significantly higher at Fz than at Cz overall; Pa-Nb and Nb-Pb were significantly lower for 3000 Hz than for 500 Hz and clicks. CONCLUSIONS: Responses from young smokers revealed a higher amplitude and shorter latency for later AMLR waves, reflecting an arousal effect of smoking in cortical and subcortical generators. AMLR differences in older adults may be due to age-related neurochemical changes in the central nervous system. Stimulus and electrode differences plus smoking and aging effects can guide neurodiagnostic AMLR protocols, especially in young adult smokers.

Self-reported hearing difficulty versus audiometric screening in younger and older smokers and nonsmokers.

BACKGROUND: The high incidence of age-related hearing loss demands accessible, low cost hearing screenings for prevention and hearing health promotion. This study assessed performance of self report (SR) against audiometry, and prevalence of hearing difficulty when screening hearing in middle-aged and younger adults, including smokers and nonsmokers. METHODS: Prospective participants (N = 219) completed a questionnaire providing biographical, health, and smoking information. Their Yes/No responses about hearing or communication difficulty provided data for self-reported hearing loss. Eligible (N = 170) participants received a hearing test including immittance, pure-tone, and speech audiometry. The binaural pure-tone average (PTA) hearing threshold was determined; PTA decibel (dB) level indicated degree (e.g., mild) of hearing loss. All hearing screening data were coded and initially analyzed in an Access database. Statistical analyses based on conditional probability included measures of prevalence, sensitivity, specificity, and predictive value of the SR versus audiometric measures. Participants provided a urine sample for biochemical analysis to confirm smoker/nonsmoker status. RESULTS: Among all participants (N = 170), overall prevalence of self-reported hearing difficulty (15.9%) was in excellent agreement with measured, mild hearing loss (16.5%). However, factoring in age and smoking revealed that SR was incongruent with audiometry because hearing loss was overestimated by smokers and younger participants and underestimated by middle-aged individuals. The SR question yielded high specificity (80-90%) overall. Specificity was highest in nonsmokers (89-94%) and younger (90-91%) individuals with lower performance in smokers and middle-aged participants. SR sensitivity was high (86-100%) only when the hearing impairment cutoff was > 40 dB (moderate loss) and > 60 dB (severe loss). Sensitivity was highest in smokers (100%), supporting SR for screenings. High negative and low positive predictive value (PPV) occurred in smokers, younger, and middle-aged persons. This study reports new sensitivity and specificity data on self-reported hearing difficulty in smokers (N = 98), younger (N = 80), and middle-aged (N = 90) adults, indicating efficacy of SR as an adult hearing screening measure. CONCLUSIONS: SR was effective as few normal-hearing persons were labeled hearing-impaired. However, audiometry should supplement SR to optimize detection of mild hearing loss for at-risk adults. Results may guide community health initiatives for hearing screenings, prevention, and health promotion. KEYWORDS: Aging; Smoking; Self Report; Health Promotion; Hearing Screening.

Effects of chronic and acute smoking on AMLRs in older and younger listeners.

Chronic and acute smoking effects on the auditory middle latency response (AMLR) were studied in older (55-81 years) and younger (19-30 years) normal-hearing listeners. Forty healthy participants were selected for one of four groups: older smokers, older nonsmokers, younger smokers, or younger nonsmokers. Biochemical urine analyses confirmed participant categorization as smoker or nonsmoker. Click-evoked AMLRs were acquired once from nonsmokers and twice (chronic condition, acute condition) from smokers. Waveform latency (V, Na, Pa) and relative amplitude (V-Na, Na-Pa) were examined with two independent variables (age, smoking) using MANOVA. Results (n=40) revealed no chronic effect of smoking in the AMLR from smokers compared to nonsmokers. However, in both older and younger smokers (n=20), Na-Pa amplitude was significantly larger in the acute compared to the chronic smoking condition, indicating an acute smoking effect. There was no interaction of smoking and aging. This is a first study describing long-term, chronic and acute smoking effects on AMLRs in older compared to younger listeners. Results suggest that cigarette smoking is an important variable for AMLR research and clinical practice.

Digit speech recognition thresholds (SRT) for non-native speakers of English.

Although Central Institute for the Deaf (CID) W-1 stimuli are routinely used for speech recognition threshold (SRT) testing, they are not always familiar to new learners of English and often lead to erroneous assessments. To improve test accuracy, alternative stimuli were constructed by pairing familiar English digits. These digit pairs were used to measure SRT for 12 non-native speakers of English and 12 native speakers of English. Results indicate that digit pairs effectively measure SRT for both participant groups; and more importantly, for non-native speakers of English, digit pairs are more accurate than CID W-1 words in measuring the hearing threshold for speech. Digit-pairs have cross-linguistic appeal and should greatly facilitate accurate SRT testing for listeners with minimal exposure to English.