Comparative Analysis of Temporal Ordering Skills among Musicians

INTRODUCTION Being able to hear effectively is essential for achieving a high-fidelity representation of auditory input. This depends not only on accurate sound detection but also on efficient sensory processing of auditory information by the central auditory system.1 Temporal cues such as duration, interval, and sequence of pattern stimuli provide critical information to the auditory system. These cues govern time-related processing and are fundamental for the perception of speech and music, both of which involve rapid structural changes.2 The pitch pattern test (PPT) thus serves as a valuable tool for assessing temporal ordering abilities. By examining an individual’s ability to recognize and reproduce pitch patterns, the PPT offers insights into temporal processing skills and highlights their capacity to manage the complex temporal demands involved in perceiving speech and music.3,4Figure 1: Boxplot representation of pitch pattern test scores ­using vowel and tones between musicians and non-musicians along with the inferential analysis results using the Mann–Whitney U test.The pitch pattern test is crucial for examining interhemispheric interactions mediated by the corpus callosum, with the right hemisphere decoding pitch and contour and the left identifying sequential patterns.5,6 It remains effective in peripheral hearing loss and is sensitive to cerebral hemisphere disorders and corpus callosum dysfunction.7,8 Musicians, ­owing to training, show enhanced auditory pathway refinement, performing better than non-musicians on tone-based duration and frequency pattern tasks.9–14 However, tonal stimuli may lead to ceiling effects, as noted by Ishii et al., Fuente et al., and Neijenhuis et al.14 To address this, verbal blocks have been proposed as alternative ordering stimuli.15–18 Unlike nonverbal stimuli, verbal blocks offer greater ecological validity for speech perception, with vowels being particularly suitable given their simplicity, cross-linguistic applicability, and ease of administration. Examining temporal ordering with vowels may also provide insight into musicians’ melody recognition difficulties linked to atypical auditory processing. Accordingly, the present study compared musicians and non-musicians on the PPT using the vowel /a/ and further explored its relationship with the traditional tone-based PPT. METHOD The present study adopted a cross-sectional design and employed purposive sampling to recruit participants. Ethical approval was obtained from the Institutional Ethics Committee. All procedures were non-invasive and were explained to each participant in detail, following which informed consent was obtained. PARTICIPANTS Based on the sample size calculation with a power of 80%, and a significance level of 0.05, a minimum of 20 participants per group was required. Accordingly, data were collected from 40 young adults with normal hearing, ages 18 to 35 years, divided into two groups. Group I included 20 vocal musicians with at least five years of formal training, comprising classical singers and music trainers, while group II consisted of 20 non-musicians with no history of formal musical training or regular musical practice. Data were collected from 40 young adults with normal hearing, ages 18 to 35 years. Participants were divided into two groups: Group I included 20 vocal musicians with at least five years of formal training, comprising classical singers and music trainers. Group II consisted of 20 non-musicians with no history of formal musical training or regular musical practice. Before initiating the test procedures, a detailed case history was obtained to ensure all participants met the inclusion criteria. Otoscopic examination revealed normal findings, and pure-tone thresholds were ≤15 dB HL at 500 Hz, 1 kHz, 2 kHz, and 4 kHz. Immittance evaluation showed type ‘A’ tympanograms with the presence of acoustic reflexes. All participants also passed the Screening Checklist for Auditory Processing in Adults (SCAP-A).19 None had a reported history of otological, neurological, or radiological conditions affecting hearing, speech, language, or cognition, and were therefore eligible to proceed with the test procedures. INSTRUMENTATIOn Hearing evaluations were conducted using a calibrated two-channel Madsen Orbiter 922 audiometer with a RadioEar B-71 bone vibrator and TDH-39 headphones. Immittance testing was performed with a calibrated Interacoustics AT235. The SCAP-A was administered to screen for auditory processing difficulties.19 For the PPT evaluation, a Hewlett-Packard 15-DAOXXX system with calibrated insert earphones (Boat BassHeads 225) was used, with calibration carried out using a sound level meter. PROCEDURE All behavioural and physiological test measures were performed according to ANSI S3.1-1999 standards in a well illuminated room having optimum temperature and permissible levels of ambient noise. Hence, the study involved administration of PPT using vowel and PPT using tone among twenty musicians and twenty non-musicians. PPT using vowel /a/ included vowel /a/ of 220 Hz for ‘low /a/’ and 261 Hz for ‘high /a/’ to correspond with the musical notes A3 and C4, respectively.20 Therefore, the test consisted of a total of 30 normalized test items, each lasting 150 ms, with an interstimulus duration of 200 ms and an inter-sequence duration of 6 seconds. To facilitate a comparative analysis of the PPT results between vowel and tone conditions, the PPT tone protocol by Pinheiro and Museik was employed.21 The PPT was administered to all participants using a laptop with calibrated insert earphones, presented at 60 dB SPL. To reduce potential bias, the test ear was selected randomly. Participants completed practice trials to familiarize themselves with the procedure and confirm understanding of the instructions. For scoring, each correctly identified triad of stimuli was assigned a score of 1, while incorrect responses—including omissions or inversions—were scored as 0. All responses were recorded in written form for documentation. STATISTICAL ANALYSIS Statistical analyses were performed using the Statistical Package for the Social Sciences (SPSS, version 26). Data normality was assessed with the Shapiro–Wilk test, which indicated a non-normal distribution (p < 0.05). Accordingly, descriptive statistics were reported using medians and interquartile ranges. Group differences were analyzed with the Mann–Whitney U test, and correlations between scores on the vowel-based PPT and the tone-based PPT were examined using Kendall’s Tau-B test. RESULTS The study included forty participants from both groups, all with bilateral normal hearing sensitivity. All participants successfully completed both the vowel-based and tone-based PPT. Both musicians and non-musicians achieved higher median scores on the tone-based PPT compared to the vowel-based PPT. Musicians consistently outperformed non-musicians on both tests. A ceiling effect was observed in 19 musicians on the tone-based PPT and in 4 musicians on the vowel-based PPT (group I). In contrast, among non-musicians (group II), a ceiling effect was observed in only 5 participants on the tone-based PPT and in none on the vowel-based PPT. The Mann–Whitney U test was applied to compare performance between the two groups across both test conditions, as illustrated in Figure 1. As shown in Figure 1, musicians performed significantly better than non-musicians on the vowel-based PPT in both the right (p < 0.001, d = 0.70) and left ears (p = 0.001, d = 0.63). A similar trend was observed for the tone-based PPT, with musicians showing superior performance in the right ear (p = 0.002, d = 0.55) and left ear (p = 0.013, d = 0.44). Data variability was also lower among musicians compared to non-musicians. Furthermore, Kendall’s tau-b correlation analysis revealed a strong positive relationship between the scores of vowel-based and tone-based PPTs in both groups. The correlation was significant among musicians (τb = 0.532, p < 0.001) as well as non-musicians (τb = 0.493, p < 0.001). DISCUSSION The present study compared temporal ordering abilities of musicians and non-musicians using the vowel-based PPT with /a/ alongside the traditional tone-based PPT.20,21 Both groups demonstrated higher median scores on the tone-based PPT compared to the vowel-based PPT. One plausible explanation for the lower scores with vowels is the increased demand on interhemispheric transfer. Tone identification occurs primarily in the right hemisphere with verbal labeling in the left, whereas vowel-based tasks require decoding in the left hemisphere, transfer to the right for pattern recognition, and subsequent transfer back for labeling.22,23 This complex bidirectional interhemispheric transmission likely contributed to the relatively reduced scores on the vowel-based PPT compared to the tone-based PPT in both groups. It is noteworthy that a ceiling effect was reached by ­nineteen participants on the tone-based PPT, compared to only four participants on the vowel-based PPT in group I, and by five individuals on the tone-based PPT with none on the vowel-based PPT in group II. The added complexity of the vowel-based PPT—requiring phonological decoding, pitch discrimination, sequencing, and labeling—likely reduced ­ceiling effects, making it more suitable for assessing musicians.24,25 Musicians showed reduced response variability and significantly superior sequencing abilities with a medium effect size across both verbal and tonal tasks compared to non-musicians, consistent with evidence of music-driven neural plasticity enhancing auditory frequency sequencing.26,27 These superior auditory ordering skills among musicians may be attributed to heightened activation of the temporal region, supported by their proficiency in short-term memory tasks.28 The findings align with prior studies suggesting superior temporal processing in musicians, including violinists and singers, with the PPT proving sensitive to training-related differences.1,9,28,29 Finally, the present study revealed a strong positive correlation between tone- and vowel-based PPT scores, confirming that both reliably measure temporal ordering. Importantly, the vowel-based PPT showed fewer ceiling effects, underscoring its potential clinical utility in detecting subtle pitch-sequence perception differences. CONCLUSION The current study highlights the substantial impact of musical training on temporal sequencing, with musicians demonstrating significantly superior performance compared to non-musicians in task-specific timing mechanisms. The vowel-based PPT exhibited a relatively lower ceiling effect, suggesting potential advantages for clinical application. In addition, the strong positive correlation between the vowel and tonal PPTs supports the validity of both measures in assessing auditory temporal ordering. However, the study’s limitations, including a narrow age range and small sample size, should be addressed in future research to enhance the generalizability of the findings.