Pusat Pengajian Sains Kesihatan - Monograf

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Determination of acoustic radiation using radioear B81 bone conductor among Malaysian healthy adults
(2025-07)
Hashim, Nurnadanadhira
Bone conduction (BC) audiometry is an important clinical hearing test in determining the type of hearing loss. However, the presence of acoustic radiation (AR) produced by the bone conductor, especially at high frequencies, may compromise the validity of the hearing threshold results. This study aimed to determine the presence and influence of acoustic radiation when using the Radioear B81 bone conductor among Malaysian healthy adults. 35 participants between the ages of 18 and 30 years with normal hearing and normal middle ear function were recruited. Bone conduction thresholds were recorded in two conditions: unoccluded (open ear canal) and occluded (closed ear canal) at high frequencies: 2kHz, 3kHz, 4kHz, 6kHz, and 8kHz. The results revealed differences in BC thresholds that were statistically significant between occluded and unoccluded conditions at 3kHz, 6kHz, and 8kHz (p < 0.05), with no significant differences at 2kHz and 4kHz. Similarly, the air-bone gap (ABG) values exhibited significant reductions at 3kHz, 6kHz, and 8kHz when the ear canal was occluded, indicating the presence of acoustic radiation on the BC measures in the unoccluded condition. These findings support the hypothesis where acoustic radiation can lead to artificial BC thresholds and false ABGs, particularly at high frequencies. This study highlights the necessity of considering acoustic radiation in BC testing using the B81 transducer and suggests that clinicians should consider occlusion procedures in high-frequency BC testing for more valid audiological tests.
The pattern of personal listening device (PLD) use among university students and its impact on hearing status
(2025)
Amin, Nur Shamin Adriana Mohd
This study investigated the patterns of PLD use among university students and examined its potential impact on hearing status. PLD usage has become nearly universal in this population, especially among individuals aged 20 to 25, who often use these devices for academic and leisure purposes. A cross-sectional survey and hearing assessment were conducted involving university students to evaluate their listening behaviours, volume preferences, and the relationship to hearing outcomes. Data were collected through questionnaires and hearing assessments including pure tone audiometry (PTA) with extended high-frequency thresholds at 12kHz and distortion product otoacoustic emissions (DPOAE). Results showed that while most students perceived their listening volume as moderate, with many exceeded the safe listening level, particularly in noisy environments. A significant portion of participants who preferred higher volume levels and longer daily usage showed elevated thresholds at 12kHz and reduced DPOAE results, indicating early cochlear changes. Particularly, 32.3% reported difficulty hearing in noisy environments despite normal PTA results, suggesting the presence of hidden hearing loss. These findings highlight a gap between perceived and actual safe listening practices among young adults and underscore the importance of education on hearing conservation. The study recommends incorporating high-frequency PTA and DPOAE in routine hearing screenings for early detection of auditory damages and NIHL.
The analysis multifrequency tympanometry among Malay children aged 1-4 years old
(2025-08)
Adnan, Nur Afiqah
Tympanometry using 226 Hz probe tone is commonly employed as an excellent noninvasive test with high sensitivity and specificity used to assess middle ear function. To increase sensitivity in detecting middle ear pathology, multifrequency tympanometry is recommended. This study investigated multifrequency tympanometry (226 Hz, 678 Hz, and 1000 Hz) in Malay children aged 1–4 years to evaluate middle ear function and to provide preliminary reference values for this population. Using a cross-sectional design, 38 children (76 ears) were recruited from daycare centers and audiology clinics in Kelantan, Malaysia. All participants underwent hearing screening including otoscopy, DPOAE, and screening acoustic reflex testing followed by multifrequency tympanometry. The results of tympanometric parameters showed excellent test–retest reliability across all probe frequencies (226 Hz, 678 Hz and 1000 Hz), as indicated by intraclass correlation coefficients (ICCs). The tympanometry parameters included ear canal volume (ECV), static admittance (SA), tympanometric peak pressure (TPP) and Tympanometric width (TW). Using 226 Hz, ICCs ranged from 0.765 to 0.976, using 678 Hz ICCs ranged from 0.903 to 0.998 and 1000 ranged from 0.821 to 0.979. The Kruskal–Wallis tests showed that ear canal volume (ECV) and static admittance (SA) changed significantly across probe frequencies. Specifically, ECV was higher at 678 Hz compared to 226 Hz, and SA values were significantly different between all frequency pairs. In contrast, tympanometric peak pressure (TPP) did not show any significant differences across frequencies. Correlation using Spearman’s correlation analyses showed that in Malay toddlers aged 1–4 years, ECV and SA slightly increased with age, with the strongest correlation for SA at 678 Hz. In contrast, age had little effect on TPP and TW, as these showed weak and non-significant negative correlations. Indicating the increase in ECV and SA with Age suggests that as Malay toddlers grow, their ear canal size and middle ear compliance also increase. This reflects normal anatomical and physiological development of the middle ear system during early childhood. These findings support the clinical value of tympanometry parameters in identifying middle ear characteristics in young children and provide preliminary reference data specific to the Malay paediatric population. However, larger studies involving diverse ethnic groups are needed to establish comprehensive normative standards
Suppression effect of contralateral mobile application-based sound therapy among adults with and without tinnitus
(2025-07)
Yahya, Kamalin Mastura Mohd
Tinnitus is the perception of sound without an external auditory stimulus. Sound therapy, particularly when delivered through a mobile application, has become a readily available therapy for reducing tinnitus. This study aims to explore the suppression effect of contralateral mobile application-based sound therapy among adults with tinnitus. This intervention study involves 33 adults (61 ears), respectively 18 participants (31 ears) with tinnitus and 15 participants (30 ears) without tinnitus. Participants aged 20 to 40 years (mean = 23 ± 1.037 years) for the tinnitus group and (mean 23 + 1.952) for the non-tinnitus group, having normal middle ear function and no retrocochlear pathology. Among them, 16 percent had mild hearing loss, and 84 percent had normal hearing in the tinnitus participants. 7 percent had mild hearing loss, and 93 percent had normal hearing in non-tinnitus participants. 26 ears demonstrated pitch matching at high frequencies (2kHz – 12.5kHz). Two types of sound therapy, namely white noise and rain sounds, were administered for three minutes using the Resound Relief GN mobile application to the contralateral ear. Suppression effects were assessed with distortion product otoacoustic emissions (DPOAEs) starting from 1.5kHz until 12kHz for both groups, and a numeric rating scale was assessed only in the tinnitus group. Tinnitus participants were also asked to choose a sound preference for reducing tinnitus. 71 percent of participants preferred rain sound, whereas 29 percent preferred white noise. This preference aligns with DPOAE results, which showed a significant result of amplitude reduction at the tinnitus pitch-matched frequency using rain sound (p<0.05) with an effect size of 0.461; meanwhile, white noise did not show a significant effect (p>0.05; effect size = 0.379). When analyzed at all frequencies, in control groups, the significant enhancement was shown at 7kHz for white noise and 3kHz, 6kHz, and 12kHz for rain sound. However, in tinnitus participants, only 2kHz is found to have a suppression effect using white noise and no suppression effect using rain sound. Both stimuli showed significant tinnitus suppression effects on the numeric rating scale (p<0.05). Contralateral rain sound is more effective at pitch-matched areas, which align with the sound therapy preferences among tinnitus participants. These findings support the potential of mobile-based sound therapy in tinnitus management, with rain sound being more effective on tinnitus suppression among adults with tinnitus, and further large-scale studies are encouraged to support the findings of this study.
Comparisons of distortion product otoacoustic emissions (DPOAE) results evoked by pure tones (PT) and frequency modulated (FM) tones in normal hearing adults
(2025-07)
Pannirselvan, Darshaini
The distortion product otoacoustic emission (DPOAE) is a valuable audiological test for assessing the function of outer hair cells and other clinical applications. Stimuli such as pure tones are typically used to record DPOAE. Frequency modulated (FM) tones have recently been introduced as alternative stimuli and are now incorporated into certain commercially available DPOAE devices. However, the extent to which the FM tones surpass the conventional pure tones in effectiveness for DPOAE recordings remains insufficiently established. Therefore, this study aimed to compare the DPOAE results elicited by pure tones and FM tones. The test duration was also compared between the two stimuli. In this study that employed a repeated measures design, 32 healthy young adults (64 ears) were enrolled. All of them demonstrated normal hearing sensitivity and normal middle ear function. The DPOAE testing was carried out using the Sentiero Advanced device (Path Medical, Germany). During the testing, both pure tones and FM tones were presented at 55 dB HL with equal primary tone levels. The DPOAE responses were recorded at frequencies of 1 kHz to 10 kHz under three different noise condition such quiet, 40 dB SPL and 60 dB SPL. The test duration for each stimulus was also recorded. In the quiet condition, PT stimuli produced significantly higher SNR values than FM stimuli at 2 kHz, 3 kHz, 4 kHz, 5 kHz, 6 kHz, 7 kHz, 8 kHz and 10 kHz (p < 0.05). Under 40 dB SPL, PT showed significantly higher SNR at 1 kHz, 3 kHz, 4 kHz, 5 kHz, 7 kHz and 8 kHz, whereas FM was significantly higher at 2 kHz (p = 0.014) and 9 kHz (p = 0.019). At 60 dB SPL, PT stimuli produced significantly greater SNR values at 4 kHz (p = 0.001) and 6 kHz (p = 0.047). For amplitude, PT stimuli elicited significantly higher responses at 4 kHz and 5 kHz in both quiet and 40 dB SPL conditions (p < 0.05), while FM was significantly higher only at 8 kHz in the 60 dB SPL condition (p= 0.021). FM stimuli required significantly longer test durations in all conditions where quiet (median = 48.5 s), 40 dB SPL (76.25 s) and 60 dB SPL (183.75 s) compared to PT (38 s, 39 s and 94.25 s respectively, p < 0.001). In conclusion, it appears that the conventional pure tones are still the preferred stimuli for recording DPOAE as it produces emissions with significantly higher amplitudes and higher SNRs in short durations.

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