Cila Umat

Effects of Age and Working Memory Capacity on Pitch Pattern Sequence Test and Dichotic Listening

This study assessed the effects of age and working memory capacity on dichotic listening and temporal sequencing. Double Dichotic Digit Test (DDT), Pitch Pattern Sequence Test (PPST) and Digit Span Test were administered on 40 healthy adults with hearing thresholds of not greater than 30 dB HL across octave frequencies from 250 to 4000 Hz. Twenty young (20–30 years old) and 20 older (50–65 years old) adults were included in the study. Results showed that the older group had significantly lower scores in DDT, PPST and working memory capacity measures than the young subjects. Working memory capacity was positively correlated with PPST but not with DDT, suggesting that DDT might be more auditory-modality-specific than PPST.

Design and implementation of least mean square adaptive filter on Altera Cyclone II Field Programmable Gate Array for active noise control

This paper presents a design and implementation of least mean square (LMS) adaptive filter for use in active noise control (ANC) application. The filter has been designed and synthesized with Altera Quartus II development platform and implemented on Cyclone II FPGA available on Altera DE2 development board. Architecture of the adaptive filter is based on conventional multiplier-adder to realize the multiply and accumulate (MAC) operation for FIR, implementing 64 filter tap with 9- bit signed integer coefficients. A uniform random signal with the bandwidth of 24 KHz is used as the test and reference signal for the filter verification. This signal is generated internally on FPGA based on LFSR technique. Performance of the filter is evaluated by means of convergence speed (with different step size, µ ) and comparison of adaptive filter coefficients with the unknown system. A fixed filter is programmed to behave as a bandpass FIR Hamming-type window with the cut-off frequency from 250Hz to 3400Hz to act as the unknown system. The results conclude that the LMS adaptive filter designed have successfully adapted with the unknown system with the fastest convergence speed of 1.46 ms at 1/210 step size.

Implementation of active noise control for hearing test application using PC

Hearing screening test is a method to determine the disorder in human ears. Conventional audiometer and an audiologist are required in order to perform the hearing screening test. However, this procedure is difficult to be implemented especially in a remote site such as factory or school due to the ambient noise which may cause inaccuracy in the test. In this work, the application of active noise control (ANC) is proposed to reduce the ambient noise using a personal computer in hearing screening test. The ANC algorithm was implemented using a computer with data acquisition modules and LabVIEW software. The results showed that the anti-noise was successfully generated in the electrical domain but no reduction was observed in the acoustic domain. The ANC is a deterministic application that requires real-time operating system to respond to the input with precisely timed output. In order to have an effective ANC system, the processing time has to be less than 0.125 ms at 8 KHz sampling rate.

Development of a computer-based automated pure tone hearing screening device: a preliminary clinical trial

Abstract Hearing screening is important for the early detection of hearing loss. The requirements of specialized equipment, skilled personnel, and quiet environments for valid screening results limit its application in schools and health clinics. This study aimed to develop an automated hearing screening kit (auto-kit) with the capability of realtime noise level monitoring to ensure that the screening is performed in an environment that conforms to the standard. The auto-kit consists of a laptop, a 24-bit resolution sound card, headphones, a microphone, and a graphical user interface, which is calibrated according to the American National Standards Institute S3.6-2004 standard. The auto-kit can present four test tones (500, 1000, 2000, and 4000 Hz) at 25 or 40 dB HL screening cut-off level. The clinical results at 40 dB HL screening cut-off level showed that the auto-kit has a sensitivity of 92.5% and a specificity of 75.0%. Because the 500 Hz test tone is not included in the standard hearing screening procedure, it can be excluded from the auto-kit test procedure. The exclusion of 500 Hz test tone improved the specificity of the auto-kit from 75.0% to 92.3%, which suggests that the auto-kit could be a valid hearing screening device. In conclusion, the auto-kit may be a valuable hearing screening tool, especially in countries where resources are limited.

Active Noise Control for Hearing Screening Test: Simulation and Experiment

A hearing screening test is a method to determine human ear disorders and conventional audiometers and audiologists are required to perform the test. However, this procedure is difficult to implement, especially in a remote site such as a factory or a school due to the ambient noise that may cause test inaccuracy. In this work, the application of active noise control ANC is proposed to reduce the ambient noise using a personal computer in a hearing screening test. The ANC algorithm was simulated in MATLAB software and implemented using a computer with data acquisition modules and LabVIEW software. Results show that anti-noise was successfully generated in the electrical domain but no reduction was observed in the acoustic domain. ANC is a deterministic application that requires a real-time operating system to respond to the input with precisely timed output. To have an effective ANC system, the processing time has to be less than 0.125 ms at 8 KHz sampling rate.

Patterns of recognition of Arabic consonants by non-native children with cochlear implants and normal hearing

Objective: This study examined the patterns of recognition of Arabic consonants, via information transmission analysis for phonological features, in a group of Malay children with normal hearing (NH) and cochlear implants (CI). Method: A total of 336 and 616 acoustic tokens were collected from six CI and 11 NH Malay children, respectively. The groups were matched for hearing age and duration of exposure to Arabic sounds. All the 28 Arabic consonants in the form of consonant–vowel /a/ were presented randomly twice via a loudspeaker at approximately 65 dB SPL. The participants were asked to repeat verbally the stimulus heard in each presentation. Results: Within the native Malay perceptual space, the two groups responded differently to the Arabic consonants. The dispersed uncategorized assimilation in the CI group was distinct in the confusion matrix (CM), as compared to the NH children. Consonants /ħ/, /tˁ/, /sˁ/ and /ʁ/ were difficult for the CI children, while the most accurate item was /k/ (84%). The CI group transmitted significantly reduced information, especially for place feature transmission, then the NH group (p < 0.001). Significant interactions between place-hearing status and manner-hearing status were also obtained, suggesting there were information transmission differences in the pattern of consonants recognition between the study groups. Conclusion: CI and NH Malay children may be using different acoustic cues to recognize Arabic sounds, which contribute to the different assimilation categories’ patterns within the Malay perceptual space.

Community Service Learning among Health Sciences and Medical Undergraduates at a Malaysian setting: Providers’ and Recipients’ Portraits

Abstract Community Service learning (CSL) or Community engagement integrated teaching and learning (CEITL) offers reciprocal learning to both the providers and recipients. While it is important to consider the opinions of both parties for successful CSL, limited information exists in this topic area locally. The objective of this study was to explore undergraduates′ and communities′ perceptions regarding their experience and services provided during CSL. Recollections of 12 health sciences and medical undergraduates, and 18 members of the community whom participated in CSL programmes were sought using focus group discussions. This included their understanding of the programme, its benefits, challenges and their solutions and preferred activities. Undergraduates perceived CSL as an activity considered important to provide interactions between students and community. The perceived benefits of CSL were enhancement of interpersonal communication skills, negotiation of mutual understanding and experiencing real life situations. Undergraduates suggested that CSL should be well planned and scheduled. The CSL was seen by the communities as a platform for the recipients′ children to learn from the undergraduates as role models, future collaboration opportunities and health knowledge sharing. Weaknesses highlighted were; unstructured schedules, lack of variation in activities and CSL programme duration been too short to be effective. Suggestions provided for improved CSL were; extended time for health screening and better planned schedules. The findings suggest that undergraduates are aware of the significance of CSL in complementing their learning whereas the community have a positive outlook regarding CSL rendered by undergraduates. Further improvements are warranted in the implementation of more effective CSL programmes.

Voice Onset Time (VOT) In Prelingually Deaf Malay-Speaking Children with Cochlear Implants

This study aimed to investigate the acquisition of the voicing contrast among Malay-speaking prelingually deaf children with cochlear implants (CI) and compared them to a group of normal hearing (NH) children. A total of 15 Malay children with 4 to 6 years duration of cochlear implant experience participated, 5 children in each age group. Secondary data from 15 NH children aged 4 to 6 years old was utilized for comparison. Speech samples were collected using a picture-naming task. There was a significant hearing age effect within the CI group. Comparing the CI and NH groups, a significant group effect was evidenced for all plosives, age effect was significant except for /b/ but there was no significant interaction between the group and age suggesting that in general, the pattern of responses was similar across age for both the study groups. Hearing age significantly correlated with the mean VOTs but not the age at implantation. The results suggest that the ability of these CI children to produce accurately the perceived voicing cues was not at par with the NH children with similar hearing experience. Longer duration of implant experience helps to improve the production of these sounds especially for the velar plosives.

Speech Perception in Noise in Normally Hearing Children: Does Binaural Frequency Modulated Fitting Provide More Benefit than Monaural Frequency Modulated Fitting?

The aim of the present study was to compare the benefit of monaural versus binaural ear-level frequency modulated (FM) fitting on speech perception in noise in children with normal hearing. Reception threshold for sentences (RTS) was measured in no-FM, monaural FM, and binaural FM conditions in 22 normally developing children with bilateral normal hearing, aged 8 to 9 years old. Data were gathered using the Pediatric Malay Hearing in Noise Test (P-MyHINT) with speech presented from front and multi-talker babble presented from 90°, 180°, 270° azimuths in a sound treated booth. The results revealed that the use of either monaural or binaural ear level FM receivers provided significantly better mean RTSs than the no-FM condition (P<0.001). However, binaural FM did not produce a significantly greater benefit in mean RTS than monaural fitting. The benefit of binaural over monaural FM varies across individuals; while binaural fitting provided better RTSs in about 50% of study subjects, there were those in whom binaural fitting resulted in either deterioration or no additional improvement compared to monaural FM fitting. The present study suggests that the use of monaural ear-level FM receivers in children with normal hearing might provide similar benefit as binaural use. Individual subjects’ variations of binaural FM benefit over monaural FM suggests that the decision to employ monaural or binaural fitting should be individualized. It should be noted however, that the current study recruits typically developing normal hearing children. Future studies involving normal hearing children with high risk of having difficulty listening in noise is indicated to see if similar findings are obtained.