Investigation of Cognitive-Motor Interference in Dual Tasking

Introduction This study examined how Dual Tasking interferes with task performance. When performing two tasks simultaneously, interference can occur, which means that the performance or outcome of each task could be affected.

The motor task consisted of maximal voluntary gripping, while the simultaneous cognitive task involved Serial X-Subtraction. The study focused on forearm muscle electrical activity (mV), grip strength (N), and success rate (%) in Serial X-Subtraction during Dual Tasking compared to Single Tasking. This study was conducted within the Czech-German neurological Interreg project.

Material and Method Twelve healthy adults aged 18 and above were recruited. Five sensors were attached to flexors and extensors of the stronger forearm using Delsys EMG Sensors. For the motor task, participants were instructed to perform maximum voluntary contraction (MVC) three times for five seconds each.

For assessing the cognitive task performance, which was evaluated using the calculated success rate, participants subtracted from various numbers between 50 and 100 for two and a half minutes (Serial-X-Subtraction). The Dual Task required participants to perform the previously described tasks simultaneously.

In order to compare the results, a statistical analysis was performed using the t-test for dependent samples and the Wilcoxon test for non-normally distributed data.

Results The participants’ average age was 32.4 years (SD=13.45), with 9 subjects being female and 2 male (dropout n=1). Compared to the Motor Task (M=83.50 μV; SD=58.52; 95% CI [44.18, 122.81]) the participants achieved significantly lower (p<.006) electrical activity in the forearm muscles during Dual Tasking (M=60.70 μV, SD=46.78; 95% CI [29.28, 92.13]). Grip strength also decreased significantly (p=.0045) in the Dual Task (M=211.60 N, SD=53.77; 95% CI [197.83, 274.92]) compared to the Single Motor Task (M=236.38 N, SD=57.37; 95% CI [175.48, 247.72]). The success rate did not significantly differ (p=.24) between the Cognitive Task (M=0.90, SD=0.11; 95% CI [0.82, 0.97]) and the Dual Task (M=0.93, SD=0.09; CI [0.87, 0.99]).

Conclusion The transferability of the results to the overall population is limited due to the small sample size, unequal gender distribution, and a low average age. The researchers suspect a subconscious prioritization of the Cognitive Task during Dual Tasking through a division of limited attention resources of the central nervous system.

In general, the findings of this study are closely aligned with the key points of the Central Capacity Sharing Model [1] and the Bottleneck Theory [2]. For future research, it is essential to consider a larger sample size, a more balanced gender distribution, and the inclusion of diverse age groups in order to achieve more reliable results.

Publication History

Article published online:
21 May 2025

• References

• 1 Friedman A., Polson M.C., Dafoe C.G., Gaskill S.J.. Dividing attention within and between hemispheres: testing a multiple resources approach to limited-capacity information processing. Journal of experimental psychology. Human perception and performance 1982; 8: 625-650
• 2 Navon D., Miller J.. Role of outcome conflict in dual-task interference. Journal of experimental psychology. Human perception and performance 1987; 13: 435-448