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Handedness-Related Differences in Regional Alpha-Band Power During a Verbal Task in Students: A Quantitative EEG Study
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Behnoosh Hamedali *1   , Leila Mahdizadeh Fanid , Shahram Vahedi |
| 1- , behnooshhamedali@yahoo.com |
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Abstract: (278 Views) |
Background: Handedness is associated with individual variability in the lateralization of language functions; however, evidence regarding regional differences in alpha oscillations between right- and left-handed individuals during the active processing of verbal information remains limited. This study compared absolute alpha-band power in frontal, temporal, parietal, and occipital regions between right- and left-handed university students while they performed a verbal task.
Methods: This cross-sectional comparative study included 60 students at the University of Tabriz (35 right-handed and 25 left-handed). Handedness was determined using the 13-item Chapman and Chapman Handedness Questionnaire. The verbal task comprised 20 questions from the Information subtest of the Wechsler Adult Intelligence Scale. During task performance, EEG activity was recorded from 19 channels positioned according to the International 10–20 System at a sampling rate of 250 Hz. After artifact-contaminated segments were excluded, absolute alpha-band power (8–13 Hz) was extracted for eight brain regions. The groups were compared using Welch’s t tests, p values were adjusted with Holm’s procedure, and Hedges’ g was calculated as the effect-size index.
Results: Mean absolute alpha power was descriptively higher in the right-handed group across all regions examined. The largest difference occurred in the left frontal region, where mean absolute alpha power was 57.79 μV² in right-handed participants and 32.68 μV² in left-handed participants. This difference remained significant after Holm correction and had a large effect size, Welch’s t(55.60) = 4.61, adjusted p < .001, Hedges’ g = 1.16. The right temporal difference was significant at the unadjusted level but did not remain significant after Holm correction. No significant group differences were found in the remaining regions.
Conclusion: Handedness may be associated with a region-specific pattern of alpha-power regulation during the processing and retrieval of verbal information. Greater left-frontal alpha power in right-handed participants may reflect group differences in inhibitory regulation, allocation of attentional resources, or control of semantic retrieval. Nevertheless, this finding alone does not indicate greater cortical activation, superior verbal performance, or the direction of language lateralization. |
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| Keywords: Absolute Alpha-Band Power, Cerebral Lateralization, Handedness, Quantitative Electroencephalography, Verbal Task |
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Full-Text [PDF 1143 kb]
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Article Type: Original Research |
Subject:
Health
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