1) Use of active music-supported therapy for stroke rehabilitation
Active music-supported therapy is a promising technique for motor rehabilitation after stroke (Schneider et al., 2007, Schneider et al., 2010, Villeneuve et al., 2014, Tong et al., 2015). It involves training the patient to play a musical instrument—a complex sensorimotor task that incorporates elements of rhythm production with precise timing demands and immediate auditory feedback about one’s movement. We have developed a novel music-supported therapy for motor function rehabilitation for stroke based on acoustic guitar playing. This task incorporates inter-limb coordination and includes rich auditory feedback paired with movements. Playing a guitar requires strumming (rhythmic movement) and simultaneously switching chords (discrete movement), which is a complex motor task that requires substantial training even for neurologically intact individuals. In order to simplify the task of chord fretting for individuals with hemiparesis due to stroke, we have developed a guitar prototype incorporating an electro-mechanical device that can automatically depress the strings into any chord in the first four frets of the guitar, allowing users to play the guitar without the ability to form chords using fingers.
- Dechenaud, M., Laidig, D., Seel, T., Gilbert, H.B., Kuznetsov, N. A. (submitted). Development of Adapted Guitar to Improve Motor Functions After Stroke: Feasibility Study in Young Adults. 41st IEEE EMB Conference on Engineering in Medicine and Biology (EMBC), Berlin, Germany.
2) Coordination of bimanual rhythmic and discrete movements
This research line is a component of a larger project to develop an adapted guitar for individuals with movement disorders affecting dexterous use of the arm and hand. The basic scientific premise of is that human movement control system combines rhythmic and discrete motor primitives (Schaal et al., 2004) to achieve complex motor repertoire. Guitar playing is one such action, where the rhythmic movement of the strumming arm is combined with the discrete movements of the hand used to fret the chords. The aim of the proposed study is to evaluate how people learn to coordinate simultaneous rhythmic and discrete actions in a simple experimental setting analogous to guitar playing. In these projects we are exploring contribution of execution vs. planning processes to rhythmic-discrete movement interference, modulation of interference when coordinating upper vs. lower extremity movements, and effects of task instruction.
3) Attentional focus effects on motor performance
Adopting an external focus of attention as opposed to an internal focus of attention is beneficial for learning of motor skills (Wulf, 2013). An external focus of attention is defined as attention directed to the effects of one’s movement on the environment, whereas internal focus of attention is directed to one’s own body movements (Wulf, Höβ, & Prinz, 1998). In this study we examine the extent to which the attentional focus effects on motor performance are influenced by the presence of temporal constraints on action (performing actions in a fast vs. slow paced manner) and the presence of body-relevant visual information. We also compare the performance characteristics in the virtual reality setup and physical setup of this task.
- Raisbeck, L., Yamada, M., Diekfuss, J.A., Kuznetsov, N. A.(submitted). The effects of attentional focus instructions and task difficulty in a paced fine motor skill. Journal of Motor Behavior.
4) Characterizing postural sway variability in health and disease.
Even when attempting to stand perfectly still, there is always some remaining movement in the body, termed postural sway. Postural sway variability involves multiple non-stochastic (non-random) components that could be identified using a method called adaptive fractal analysis (AFA). Based on characteristics observed in the AFA plots of the center of pressure profiles, I proposed a new interpretation for understanding variability occurring during postural control—whereby the nervous system uses a strategy to maintain balance, termed on-off intermittency, where sway is allowed to continue until it reaches a given threshold, at which point the brain interferes to bring the body back from that threshold to avoid a fall. This information is crucial for fall prevention and fall-risk monitoring because people with increased fall risk may have altered variability patterns in postural sway. I have recently published a paper describing my work characterizing balance efficacy in older adults. In this paper I showed that postural sway variability is more closely related to functional balance level (measured by Berg Balance Scale) when the standing still task has an explicit task goal (online visual feedback in relation to target standing position was provided) as opposed to simply standing still without any explicit goal.
- Kodama, K., Yasuda, K., Kuznetsov, N. A., Hayashi, Y., & Iwata, H. (2019). Balance Training with a Vibrotactile Biofeedback System Affects the Dynamical Structure of the Center of Pressure Trajectories in Chronic Stroke Patients. Frontiers in Human Neuroscience, 13, 84.
- Kuznetsov, N. A., Bonnette, S., Gao, J., & Riley, M. A. (2013). Adaptive fractal analysis reveals limits to fractal scaling in center of pressure trajectories. Annals of Biomedical Engineering. Advance online publication. doi: 10.1007/s10439-012-0646-9.
- Kuznetsov, N. A. & Riley, M. A. (2015). The role of task constraints in relating laboratory and clinical measures of balance. Gait & Posture, 42, 275-279.