Effects of dual-task training on cognitive-motor learning and cortical activation: A non-randomized clinical trial in healthy young adults

Abstract

Dual-task (DT) training, which involves the simultaneous execution of cognitive and motor tasks, has been shown to influence task performance and cortical activation, yet evidence on the effects of DT training and cortical activation for complex postural control tasks remains limited. This study investigated the immediate and retention effects of a one-week DT training program on DT learning, performance in DT and single-task conditions, and activation in bilateral prefrontal (PFC) and vestibular cortices in healthy young adults. Eighteen individuals (age = 22.39 ± 1.73 years) participated in the study. The DT paradigm involved a dynamic stability platform (motor task) paired with either a simple or complex auditory reaction time (RT) task (cognitive). Participants completed 20-25 minutes of DT training (18 trials/day) across five consecutive days. DT performance was measured by the duration participants maintained the stability platform within 3 degrees of the horizontal while responding to auditory stimuli. Single-task motor and cognitive performances were also assessed. Cortical activation in the PFC and vestibular cortices was measured using functional near infrared spectroscopy (fNIRS), tracking changes in oxygenated hemoglobin (HbO) concentrations. Pre-training, post-training, and one-week follow-up testing was conducted. The results demonstrate that DT training significantly improves and retains DT performance, likely due to a reduction in cognitive-motor interference. Additionally, DT training led to decreased activation in the bilateral PFC and vestibular cortices, specifically for complex DT condition, suggesting enhanced attentional resource allocation and optimized vestibular input processing, indicative of neural efficiency. Notably, these training effects also transferred to single-task cognitive and motor performances, with corresponding reductions in PFC and vestibular cortex activation, despite the lack of direct training on these tasks. This study advances our understanding of the neural mechanisms underlying DT training and underscores the critical role of practice in optimizing cognitive-motor efficiency.

Fig 1. CONSORT flow diagram of participant enrollment and retention.

CONSORT flow diagram detailing participant enrollment, allocation, intervention, follow-up, and analysis. A total of 42 participants were assessed for eligibility, with 18 meeting the inclusion criteria and completing the study. The diagram illustrates the process from initial assessment through to the final analysis, including reasons for exclusion and participant retention throughout the study phases.

Fig 2. Experimental procedure timeline and sequence of visits for dual-task training.

Schematics of the study protocol. The experimental design includes pre-training, post-training, and follow-up assessments of dual-task (DT) performance, single-task cognitive performance (measured as reaction time, RT), and single-task motor performance (measured as balance time in seconds). Functional near-infrared spectroscopy (fNIRS) was utilized to measure cortical activation in the bilateral prefrontal and vestibular cortices. The DT training protocol involved the simultaneous execution of cognitive tasks (simple and complex auditory RT) and motor tasks (balance) for 20–25 minutes per day across five consecutive days. Participants completed 18 DT trials each day, with each trial consisting of 30 seconds of task performance followed by 30 seconds of rest.

Fig 3. fNIRS source-detector array setup. Red Indicates Source; Yellow Indicates Detector.

This figure illustrates the arrangement of the functional Near-Infrared Spectroscopy (fNIRS) system utilized in the study. The setup features multiple source-detector pairs, with sources indicated in red and detectors in yellow. The sources emit near-infrared light that penetrates the cortical tissues, while the detectors capture the transmitted light to assess changes in cortical oxygenation. The strategic placement and configuration of these components are essential for accurately monitoring cortical activation in the PFC and vestibular cortices during cognitive, motor, and DT conditions.

Fig 4. Study Block Design: Task Structure and Trial Distribution.

A: 30 seconds rest; B₁: auditory RT (cognitive) task (simple RT or complex RT tasks); B2: balance (motor) task; B3: auditory cognitive task + balance tasks (DT). Each participant preformed six trials with three simple RT trials and three complex RT tasks.

Fig 5. Dual-task learning across training visits for simple and complex reaction times.

Dual-task (DT) performance during SRT and CRT across five training visits. Participants were required to maintain the stability platform within 3 degrees of horizontal while simultaneously responding to SRT and CRT. DT performance, indicated by the average number of seconds in balance during 30-second trials, progressively improved over the course of the five training visits (Visits 2–6) for both cognitive conditions. Data points represent the mean performance across 18 trials, and error bars denote the 95% confidence interval.

Fig 6. Dual-task (DT) performance during simple and complex cognitive conditions.

DT performance during pre-, post, and follow-up training visits. DT performance improved and retained with training. The bars denote the mean and error bars denotes standard deviation.

Fig 7. Median reaction time (RT) across pre-, post-, and follow-up testing for simple and complex conditions.

RT decreased and retained with training for simple as well as complex cognitive conditions, which indicates faster information processing time.

Fig 8. Motor performance across pre-, post-, and follow-up testing for simple and complex cognitive conditions.

Balance time increased and retained with training.

Fig 9. A) Prefrontal cortex (PFC) activation during simple reaction time task (SRT); B) Vestibular cortex (VEST) activation during SRT; C) PFC activation during complex reaction time (CRT); D) VEST activation during CRT; E) PFC activation during balance task; F) VEST activation during balance task; G) PFC activation during SRT dual-task; H) VEST activation during SRT dual-task; I) PFC activation during CRT dual-task; J) VEST activation during CRT dual-task; * FDRp < 0.001.