Digital therapy to improve stuttering symptoms in patients with a deficit of spectral power in the EEG beta frequency band

Abstract

BackgroundStuttering is a speech disorder that affects more than 70 million people worldwide, limiting their ability to communicate and socialize. In recent decades, several studies have demonstrated a link between stuttering and a deficit of β electroencephalographic (EEG) power.Aim and MethodsThis study investigates the efficacy of a novel auditory neuro modulating technology that leverages euphonic music tracks with broad-spectrum binaural beats to induce selective EEG spectral power changes. Adults with stuttering (AWS, n=6) and participants from the control group (n=6) were exposed to euphonic binaural stimuli for 5 minutes. The EEG and electrocardiographic (ECG) bio-signals were recorded prior, during, and after exposure.ResultsDuring standard reading tasks without stimulation, β-power in the left hemisphere in the adults without stuttering and with stuttering differed. The left-right hemisphere asymmetry in β-wave power was observed in the control group but not in AWS. After the stimulation, the power of β-band in AWS participants in the left hemisphere increased 1.54-fold, while changes in the right hemisphere activity were not significant. Average β-band power within left frontotemporal area and temporoparietal junction after stimulation in AWS participants shows an increase of β-band in left frontotemporal junction by 1.65-fold and in left temporoparietal by 1.72-fold. The changes in the quality of speech were assessed based on the speech rate and the rate of speech disfluencies evaluated by speech therapists. The rate of disfluencies dropped significantly after the stimulation (median 74.70% of the baseline rate), but the effect was not significantly different from the baseline 10 min later (median 65.51% of the baseline rate). Similarly, the speech rate significantly increased immediately after the stimulation (median 133.15%) but was not significantly different 10 min later (median 126.63% of the baseline rate). In this study, we found significant correlations of β-activation level in left temporoparietal projection (Spearman ρ=-0.54,) and left frontotemporal area (Spearman ρ=-0.58) with disfluency rate of speech.ConclusionsWe show for the first time that auditory binaural beats stimulation can substantially improve speech fluency in AWS and its effect is related to boost of EEG β-band power in speech-production centers. The changes in β power are detected immediately after the exposure and persist 10 min later. Additionally, these effects are accompanied by a reduction in stress level as monitored by ECG markers. This suggests that auditory binaural beats stimulation temporarily improves speech quality in AWS by increasing β-band power of EEG in speech centers of the brain.