Journal of All India Institute of Speech and Hearing

Editorial

2021-02-25T11:52:12+00:00

Neural Representation of Complex Sounds in the Human Auditory Brainstem

2021-02-25T11:54:36+00:00

Phase-locked neural activity in the brainstem generating the human frequency following response (FFR) has been shown to preserve neural information about certain spectrotemporal attributes of complex sounds that likely contributes to the perception of speech, language, music, and segregation of concurrent sound streams. Here we review some evidence in support of the view that the temporal pattern of neural activity in the FFR does preserve information relevant to the representation of spectra and pitch of complex sounds. Specifically, FFR spectra for both steady state and time variant complex sounds show clear peaks at formant related harmonics that follow the changes in formant frequencies for time-variant sounds. Similarly, neural information relevant to steady- and time-variant pitch, pitch shifts, and changes in pitch salience are well preserved in the FFR and exhibits a strong correlation with behavioral measures. For inharmonic, frequency shifted, and unresolved harmonics stimuli that produce pitch shifts or multiple pitches, neural activity relevant to these perceived changes in pitch is primarily contained in the neural representation of the temporal fine structure (TFS). Both reverberation and noise degrade the neural representation of envelope and TFS with phase locking to ENV showing greater resilience. Overall, these results clearly suggest that the FFR provides a robust physiologic window to evaluate the nature of neural representation of spectra and pitch of complex sounds in normal and impaired ears, age related changes in neural encoding, and to understand the role of experience in shaping subcortical processing and its application to re-training and perceptual learning.

Effect of Syllable Complexity on Speech Disfluencies of Kannada Speaking Adults Who Stutter

2021-02-25T11:59:51+00:00

Stuttering is a speech disorder that is described by involuntary disruptions in natural flowing speech. Literature focuses on the variation in the typology and frequencies of disfluencies in both children and adults who stutter. Speech disfluencies across languages have been explored in the western context and distinct findings have been reported on the occurrences of stuttering on phonetically complex structures along with the presence of cluster disfluencies. The current study aims to investigate the effect of syllable complexity (words with and without consonant clusters) on the speech disfluencies of Kannada speaking adults who stutter. Thirty Kannada speaking adults with stuttering in the age range of 18 to 30 years were considered. A standardized Kannada reading passage constituting of words with and without consonant clusters was used. Results indicated that WCC had higher percentages of disfluencies as compared to WWCC in adults with moderate as well as severe stuttering. However, these findings were not statistically significant. Also, cluster disfluencies on words with consonant clusters were observed to be greater in adults with severe stuttering when compared to adults with moderate stuttering. Concerning the typology of cluster disfluencies, a combination of Stuttering like Disfluencies (SLD-SLD type) was observed that indicated involvement of the motoric component of stuttering. Results have been discussed with regard to the Covert Repair Hypothesis and EXPLAN theory.

Role of Rehearsal Language in Working Memory

2021-02-25T12:02:50+00:00

The current study investigates the effect of the language of rehearsal on working memory spans. We hypothesised that, in bilinguals, rehearsal in a language whose digits are shorter in length leads to better working memory spans compared to rehearsals in a language with longer digit length. We measured backward digit spans in 24 bilingual individuals with proficiencies in Kannada (native language) and English rated as ‘good’ or better. The backward digit spans were measured under three conditions; (i) no instructions regarding rehearsal language, (ii) overt rehearsal in Kannada, (iii) overt rehearsal in English. Digits were presented only in Kannada language for all the three rehearsal conditions. Results indicated that rehearsal in English (shorter digit length) resulted in higher scores than the other two conditions. The results provide evidence to the existence of word-length effects even at the level of rehearsal strategies.

Gesture Identification for Nouns and Verbs in Typically Developing Children

2021-02-25T12:06:23+00:00

The relationship between gesture and verbal language was explored using gesture identification in childrens. A noun-verb distinction is well evidenced across various language systems, and therefore, a set of noun and verb gestures were considered for the gesture identification task. Typically developing children (TDC) of 3rd, 4th and 5th grade with an age range of 8-8.11, 9-9.11 and 10-10.11 years respectively served as participants for the study. The participants were presented 15 noun, and 15 verb gestures and were instructed to name them. The scores were tabulated for both nouns and verbs for the three groups of participants. Kruskal-Wallis test was used to compare the performance of participants across grades. The results revealed no difference in gesture identification scores across the participant groups, thus, showing an absence of a developmental trend in gesture identification in the population considered. Wilcoxon’s signed rank test was performed as a within-group analysis, which revealed a significant difference in identifying noun vs. verb gestures in the participant groups. Further, it was inferred that the verb gestures were identified better in comparison to the noun gestures within each group. The results highlight the noun-verb distinction of gesture decoding in TDC.

Manipulation of Signal-to-Noise Ratio to Compensate for Variations in Word Identification Scores Due to Change in Masker

2021-02-26T09:55:45+00:00

The type of masking noise is known to affect speech identification. Some maskers are known to have a greater masking effect on speech than others. Thus, the study aimed to investigate whether manipulating the signal-to-noise ratio (SNR) of a masker can compensate for variations in word identification scores obtained due to change in the type of masker. To investigate this, the scores obtained by 20 children on a speech identification test using an 8-talker babble was compared with that obtained on a word identification test in the presence of white noise. The former test was evaluated at 0 dB SNR using the ‘Speech perception-in-noise in Kannada’ (SPIN-K) and the latter in three different SNRs (0 dB, -5 dB, & -10 dB) using the ‘Kannada Word identification-in-white noise’ (WIWN-K). Speech babble was found to have a greater masking effect at 0 dB SNR, resulting in poorer speech identification scores than white noise. However, the speech identification scores obtained using white noise at -10 dB SNR was equivalent to that of scores obtained with speech babble at 0 dB SNR. The study highlights that the masking effect of continuous white noise can be made equivalent to the masking effect of an 8-talker speech babble by reducing the SNR.

Effects of Pressure Sweep Factors on Acoustic Immittance Measures in Ears with Normal/Low and High Acoustic Admittance

2021-02-26T09:58:39+00:00

Normal middle-ear function has a tympanometric peak pressure (TPP) of ~0 daPa, with a sharp decline as the air pressure withdraws away from 0 daPa. However, there is no information about variations in the TPP because of changes in pressure sweep direction and sweep rate in ears with different acoustic admittance values. This study investigated the effects of pressure sweep direction and rate on the TPP and acoustic admittance values in individuals with high- and normal-/low acoustic admittance middle-ears (25 ears with healthy middle-ear acoustic admittance [Group I] and 19 ears with high middle-ear acoustic admittance [Group II]). We explored changes in ipsilateral acoustic reflex thresholds (ARTs) monitored with the obtained TPPs. Tympanometry was performed under four experimental conditions in two pressure directions (conventional and reverse) and at two pressure rates (high and low). In addition, we measured ipsilateral ARTs at octave frequencies from 500 to 4000 Hz for the obtained TPPs. We observed significant differences in the TPPs, but not in acoustic admittance measures, in both groups. Analysis of ipsilateral ARTs monitored at different TPPs showed significant differences between the four experimental conditions in Group II at octave frequencies >1000 Hz but not in Group I. Low (better) ARTs were elicited with lower variability at a TPP obtained in the conventional pressure sweep direction but at a low pressure sweep rate of 50 daPa/s. Therefore, tympanometric measurements are suggested to be performed at a low pressure sweep rate and in a conventional pressure sweep direction, especially for people with increased acoustic admittance.

Prevalence of Children At-Risk for Developing Communication Disorders in the Urban Primary Schools of Dharwad

2021-02-26T10:00:53+00:00

It is essential to estimate the prevalence of those at-risk for developing communication disorders in a specific area for their prevention, early identification and early rehabilitation. Availability of prevalence data helps in effective planning and implementation of rehabilitation services. The present study aimed to study the prevalence of school-going children at-risk for developing communication disorders and to estimate the distribution of such conditions across gender and grade in urban schools of Dharwad, North Karnataka. A total of 2241 children from Pre-Kindergarten (Pre-KG) to sixth grade were screened for risk of having communication disorders. The overall prevalence showed that around 10.3% of total children screened had risk of developing communication disorders. Among them, language disorders (40%) were found to be the highest followed by speech (29%) and hearing (9%). Further, 5% of the children had multiple disorders. Across gender, the prevalence was more in boys (61.2%) than girls (38.7%). Further, grade wise distribution showed higher occurrence of communication disorders from Upper-Kindergarten (UKG) to Grade 3. It can be concluded from the study that there is a high prevalence of school-going children at-risk for developing communication disorders. Hence, it is important to conduct regular speech and hearing screening in schools to enable early identification of the same.