Stress Perception among School-age Children

Abstract

Introduction: Prosody is the inflection embedded in speech. The perception of prosody is necessary to understand a spoken utterance, especially to appreciate the intricacies of languages. The influence of prosody is also beyond the boundaries of a sentence and provides speech its emotional tone. Prosody or the supra-segmental is made of stress (accent), intonation (pitch patterns) and the rhythmic (timing) pattern of language. Acoustically, it is described in terms of the parameters of pitch (fundamental frequency), intensity (amplitude), and duration and their co-variations. Perceptually, stress is the acoustic prominence of a target segment over the other segments in continuous speech. Assessing stress perception among typically developing children has wide range of applications including development of prosody markers which are essential for normal speech development. Such insights in the developmental norms will aid in identifying children with (or at risk) for communication disorders such as Specific Language Impairment (SLI), hearing impairment (HI), etc. Literature review suggests gross prosody deficits in children with communication disorders and there is lack of assessment tools to evaluate the prosodic skills. Hence the present study aimed to develop norms for stress perception among typically developing children in the age range of 5–8 years. Method: The investigation included a total of 90 participants (45 boys and 45 girls) in the age range of 5–8 years (15 boys & 15 girls in each age group: 5–6 years; 6–7 years & 7–8 years). The participants were screened for any disability using the World Health Organization (WHO) 10-disability screen questionnaire. The study included two types of tasks—verbal and nonverbal tasks (based on the stimuli used). Synthetic tokens were created using Praat software (Version 6.0.48) and the stimulus was presented through headphones (Philips Stereo SBC HP 100) to the participants at a comfortable listening level (75 dB). For the verbal stress task, syllable /ma/ was used as the stimuli and for the nonverbal stress task, piano tones were used. The fundamental frequency, duration and intensity of the stimuli were altered and synthesized according to the task requirements. The stimuli consisted of stressed (synthetically manipulated) and unstressed (unaltered) tokens, which were presented in a binary form (for example, Stressed–Unstressed, Unstressed–Stressed and Unstressed–Unstressed). The participants were tested individually in a relatively quiet room in a school setting. Prior to the experimental testing, each participant was subjected to three practice trials in each task (that is, verbal and nonverbal). They were instructed to indicate if the binary form stimuli presented were perceived as same or different. The responses of the participants were audio recorded using digital recorder Olympus WS 100. Each token was presented thrice to the participants and two out of the three responses was considered as the final response of each participant, for both verbal and nonverbal tasks. The total testing duration was about 15–20 min for each participant. The responses from the participants were scored in terms of “0” and “1” for incorrect and correct responses, respectively. Analysis and Results: The obtained data were subjected to Shapiro Wilks test for normality and revealed non-normal distribution (that is, p≤0.05). Mann-Whitney U test revealed there was no gender effect on stress perception (z = -0.067). Further, Kruskal Wallis test revealed an overall significant difference (p≤0.05) in performance across age groups. Mann-Whitney U test revealed significant pairwise difference in performance between all the three age groups (5–6 years vs. 6–7 years (z= -4.231); 6–7 years vs. 7–8 years (z= -5.355) and 5–6 years vs. 7–8 years (z= -6.568)). Overall, there was a developmental trend for stress perception observed, that is, stress perception accuracy increased with age. All the participants performed better in nonverbal stress perception task as compared to verbal stress perception task. Implications: The findings of the study will be applicable in identifying children with communication disorders such as SLI and in improving the prosodic skills of children with HI, thereby improving their overall speech intelligibility.

Keywords: stress, communication, speech, rehabilitation, verbal

Cite this Article

Sreedevi N, Sangeetha M, Priyadharshini V. Stress Perception among School-age Children. Research & Reviews: A Journal of Bioinformatics. 2019; 6(2): 4–9p.