Brainstem Correlates of Comodulation Masking Release for Speech in Normal Hearing Adults

BACKGROUND AND OBJECTIVES: Weak signals embedded in fluctuating masker can be perceived more efficiently than similar signals embedded in unmodulated masker. This release from masking is known as comodulation masking release (CMR). In this paper, we investigate, neural correlates of CMR in the human auditory brainstem. SUBJECTS AND METHODS: A total of 26 normal hearing subjects aged 18-30 years participated in this study. First, the impact of CMR was quantified by a behavioral experiment. After that, the brainstem correlates of CMR was investigated by the auditory brainstem response to complex sounds (cABR) in comodulated (CM) and unmodulated (UM) masking conditions. RESULTS: The auditory brainstem responses are less susceptible to degradation in response to the speech syllable /da/ in the CM noise masker in comparison with the UM noise masker. In the CM noise masker, frequency-following response (FFR) and fundamental frequency (F0) were correlated with better behavioral CMR. Furthermore, the subcortical response timing of subjects with higher CMR was less affected by the CM noise masker, having higher stimulus-to-noise response correlations over the FFR range. CONCLUSIONS: The results of the present study revealed a significant link between brainstem auditory processes and CMR. The findings of the present study show that cABR provides objective information about the neural correlates of CMR for speech stimulus.

effect of the loading on dynamic stability and scapular asymmetry

Background: Scapular stabilization and neuromuscular control provide an important parameter to characterize shoulder function during dynamic activities. Many studies have confirmed the effect of the loading on scapular position and scapulohumeral rhythm. Therefore, the evaluation of stabilizer muscles involvement in scapular asymmetry may assist in the development of clinical examination and rehabilitation program. The aim of this study was to evaluate the effect of loading on dynamic stability and scapular asymmetry in basketball players

Methods: Thirty healthy male basketball players aged between 20 to 31 years old were tested. The linear distance between scapular inferior angle and T7 spinous process was measured using a caliper in 90 degrees of unloaded scaption and with 1, 2 and 4 kg loading. The difference of distances of two sides in the above 4 positions was analyzed

Results: The amount of distances difference in two sides with 1 kg loading was minimal [9.36mm]. This difference increased to 10.19 mm and 12.22 mm, with increasing the loading to 2 and 4 kg respectively; although the 4 positions of the test did not show significant differences in distances difference [p>0.05]

Conclusion: This study shows that dynamic stability of the scapula is dependent on the role of muscles, so that with increasing load on the muscles, the scapular asymmetry is more pronounced

Effect of kinesiotaping and stretching exercise on forward shoulder angle in females with rounded shoulder posture

Background: Rounded shoulder posture is a common abnormal posture in upper quarter. Kinesiotape is a new intervention that recently used in rehabilitation. There are no studies have examined the effect of kinesiotape on rounded shoulder posture. Therefore the purpose of this study was to determine the effect of scapular kinesiotaping and pectoralis minor stretching exercise on forward shoulder angle in female subjects with rounded shoulder posture

Methods: Twenty female students aged between 18 to 25 years old with rounded shoulder posture participated in this study. Then, the subjects were randomly and equally assigned to two groups: the stretch group and the stretch plus kinesiotape group. Both groups were trained for doing home exercise to stretch Pectoralis minor bilaterally for two weeks. Kinesiotape group received kinesiotape on scapular area additionally. Forward shoulder angle was measured in four sessions including pre-intervention [first session], immediately after the first intervention [second session], fourth day [third session] and at the end of two weeks [fourth session]. Two-way repeated measures ANOVA [4×2] was used for data analysis

Results: kinesiotape group showed significant within-group decrease in forward shoulder angle between first session with three other sessions [P

Conclusion: scapular kinesiotaping along with pectoralis minor stretching exercise improved rounded shoulder posture in subjects of the present study. kinesiotape is suggested as a complementary treatment with immediate effects on postural correction of rounded shoulder

Reaction time and anticipatory skill of overhead athletes with and without Scapular Dyskinesia

Scapular dyskinesia is a change in position or movement of scapula, which is highly prevalent in athletes with overhead activities. In addition to biomechanical changes in shoulder complex, neurocognitive impairments can have a significant role in its creation. Thus, this study aimed to compare neurocognitive scores between athletes with and without scapular dyskinesia. In this study, 30 athletes with overhead activities participated. Caliper and SART [Speed Anticipation and Reaction Time] sets were used for assessing subjects' scapular dyskinesia, reaction time, and anticipation skill. Athletes with scapular dyskinesia had significantly a slower visual and auditory complex choice of reaction time, and a lower auditory choice of reaction time compared to athletes without scapular dyskinesia. No significant difference was seen between two groups in terms of visual choice of reaction time and anticipation skill. Thus, athletes with scapular dyskinesia had poorer performance in more complex neurocognitive tests compared to athletes without it

[Comparison of cognitive potential P300 with high and low frequency stimulus in early onset blind subjects]

Previous studies suggest that auditory stimulus frequency in normal subjects contribute to both P300 amplitude and latency measures. As occipital cortex devotes to other modalities including auditory inputs, the purpose of this study was to determine the effects of stimulus frequency in early blind subjects. Fifteen early blind subjects [8 males and 7 females] with mean age of 25.13 +/- 4.27 years were tested. Cognitive potential P300 was recorded in response to high [1000/2000Hz] and low [250/500 Hz] frequencies auditory stimuli using an oddball task in 70 dB nHL. While participants answered to target stimulus, amplitude and latency of P300 was recorded. With high frequency stimuli, mean amplitude in early onset blind subjects obtained 14.13 +/- 5.53 micro v and was 17.59 +/- 8.17 micro v with low frequency. With high and low frequency, mean latency of P300 obtained 295.60 +/- 31.33 ms and 317.38 +/- 21.71 ms respectively. Comparison of results between two stimuli showed that there were statistically significant differences between amplitudes [p=0.008] and latencies [p=0.001] of cognitive potential P300. Changing low frequency to high frequency results in decreasing both amplitude and latency. It seems that auditory stimuli frequency affect the P300 parameters in blind subjects

[Prevalence of hearing loss and the related factors in BuAli Hospital]

Determining the prevalence of hearing loss and correlated factors in clients referring to audiology clinic of Buali hospital. This cross-sectional analytic-descriptive survery was carried out on six thousand and twenty ears of 3010 clients [1651 ,a;e and 1359 female] in Audiology clinic of Buali hospital , during Sept 2000 to Sept 2001. Hearing loss is the most common reason for referring the clients [20.5%]. 1319 ears [21.9%] Showed sensorineural hearing impairment and conductive and mixed hearing loss are observed in 1059 [17.6%] and 234 [3.9%] ears, respectedly. Hearing loss degree most cases is mild [14%] in both ears. There is no significant difference between male and female hearing threshold means [p>0.05] but a significant difference between hearing thresholds is observed in terms of age [p<0.05]. Audiogram configuration in most cases is flat [55.1%]. Otoscopic examination reveals abnormal condition in 2333 ears [38.8%] . 37.2% of the studied cases have abnormal tympanogram mostly type B [15.9%]. 2.2% of the clients wear hearing aid that mostly have B.T.E ones [1.5%]. 6.2% of the clients , depends on their hearing impairment type and degree need rehabilitation services. The results are Valid only in the context of this study and it's generaliztion needs further researches

[Temporary threshold shift by otoacoustic emission in a group of 18-25 years old with normal hearing]

Method and Material: This study was performed on 36 normal-hearing subjects aged 18-25 years for survey of temporary threshold shift [TTS] by transient evoked otoacoustic emissions

Finding: Noise can affect the pure-tone thresholds and [TEOAEs] amplitudes. When cochlea affected by noise, evaluating TEOAE is more suitable than pure-tone audiometry. Because of this test, is objective an unaffected by attention and alertness and can be evaluated in difficult to test subject and also have high carefulness and can be performed in a quiet, but not sound-proof room