The effects of different attentional focus on poststroke gait

Understanding the implication of task conditions on asymmetry in gait of post-stroke individuals using an Integrated Wearable System

Hemiplegic individuals often demonstrate gait abnormality causing asymmetry in lower-limb muscle activation-related (implicit) and gait-related (explicit) measures (offering complementary information on one's gait) while walking. Added to hemiplegia, such asymmetry can be aggravated while walking under varying task conditions, namely, walking without speaking (single task), walking while counting backwards (dual task), and walking while holding an object and counting backwards (multiple task). This emphasizes the need to quantify the extent of aggravated implication of multiple-task and dual-task on gait asymmetry compared to single task. Here, we used Integrated Wearable System and carried out a study with a group of age-matched hemiplegic (Grp_S) and healthy (Grp_H) individuals to understand the potential of our system in quantifying asymmetry in explicit and implicit measures of gait, implication of hemiplegic condition and varying task conditions on these asymmetry measures along with their clinical relevance. Results showed the potential of our system in quantifying asymmetry in both explicit and implicit measures of gait, and these measures were statistically higher (p-value < 0.05) in Grp_S than Grp_H irrespective of the task conditions. Also, for Grp_S, these asymmetry measures became more pronounced as task demand increased, and again, these measures have shown a correlation with their risk of fall specifically during more attention-demanding tasks that could be clinically relevant.

Effect of sonification types in upper-limb movement: a quantitative and qualitative study in hemiparetic and healthy participants

BACKGROUND

Movement sonification, the use of real-time auditory feedback linked to movement parameters, have been proposed to support rehabilitation. Nevertheless, if promising results have been reported, the effect of the type of sound used has not been studied systematically. The aim of this study was to investigate in a single session the effect of different types of sonification both quantitatively and qualitatively on patients with acquired brain lesions and healthy participants.

METHODS

An experimental setup enabling arm sonification was developed using three different categories of sonification (direct sound modulation, musical interaction, and soundscape). Simple moving forward movements performed while sliding on a table with both arms were investigated with all participants. Quantitative analysis on the movement timing were performed considering various parameters (sound condition, affected arm and dominance, sonification categories). Qualitative analysis of semi-structured interviews were also conducted, as well as neuropsychological evaluation of music perception.

RESULTS

For both the patient and healthy groups (15 participants each), average duration for performing the arm movement is significantly longer with sonification compared to the no-sound condition (p < 0.001). Qualitative analysis of semi-structured interviews revealed different aspects of motivational and affective aspects of sonification. Most participants of both groups preferred to complete the task with sound (29 of 30 participants), and described the experience as playful (22 of 30 participants). More precisely, the soundscape (nature sounds) was the most constantly preferred (selected first by 14 of 30 participants).

CONCLUSION

Overall, our results confirm that the sonification has an effect on the temporal execution of the movement during a single-session. Globally, sonification is welcomed by the participants, and we found convergent and differentiated appreciations of the different sonification types.

[Attentional focus instructions for therapeutic exercise in people with musculoskeletal disorders. A scoping review]

Attentional focus instructions are verbal strategies that could maximize the effects of exercise. The objective of this review was to explore and synthesize the available evidence on the incorporation of attentional focus instruction in the exercise of people with musculoskeletal disorders. A search of 11 databases was carried out until October 2020. Of 4,227 studies identified in the searches, 15 were included. The studies showed deficiencies in the conceptualization and definition of attentional focus instructions. The available evidence indicates that external focus is effective in improving motor learning and function. However, methodological limitations, clinical heterogeneity, the small number of articles included, and new experimental studies challenge the conclusions of the systematic reviews available to date. Attentional focus instructions in musculoskeletal disorders is an emerging field and requires further research. This review is a guide for future studies.

Focus of Attention in Voice Training

OBJECTIVE

The vast majority of motor learning studies investigating focus of attention have found that an external focus of attention (focusing on the effect of a movement) results in enhanced performance and learning, compared to an internal focus of attention (focusing on the body movement itself). The present study attempts to determine if the high incidence of internal focus of attention instruction that has been reported in the realm of athletics is replicated in voice training.

METHODS

Two hundred and seventy-eight singers, who were at least 18 years old and taking voice lessons, were recruited to participate in an anonymous research survey entitled "Instructions given to singers in voice lessons." The main six questions asked singers to report phrases or instructions that their studio voice teachers gave them in regard to posture, breathing and/or support, tone clarity and/or onset of tone, space and/or resonance, articulation, and reducing tension.

RESULTS

Approximately 50.83% of the total responses were classified as inducing an external focus, 39.42% were classified as internal focus, 6.48% used a combination of both internal and external focus, and 3.27% were categorized as miscellaneous.

CONCLUSIONS

The results of this study indicate that voice teachers use both external and internal attentional focus directives in the voice studio. Given the robust body of literature supporting the use of external focus, it is noteworthy that the current study found that external focus is used more often than internal focus in voice training.

Loss of Motor Stability After Sports-Related Concussion: Opportunities for Motor Learning Strategies to Reduce Musculoskeletal Injury Risk

Current best practices to direct recovery after sports-related concussion (SRC) typically require asymptomatic presentation at both rest and during a graduated exercise progression, and cognitive performance resolution. However, this standard of care results in a significantly elevated risk for musculoskeletal (MSK) injury after return-to-sport (RTS). The elevated risk is likely secondary to, in part, residual neurophysiological and dual-task motor stability deficits that remain despite RTS. These deficits present as a loss of autonomous control of gait and posture and an increased need for cognition for motor stability. Thus, the incorporation of strategies that can enhance motor stability and restore autonomous control of gait and posture during SRC recovery and RTS progression may facilitate a reduction of the elevated risk of secondary MSK injury. We provide a theoretical framework for the application of motor learning principles to restore autonomous gait and postural stability after SRC via incorporation, or targeted manipulation, of external focus, enhanced expectations, autonomy support, practice schedule variability, and dual-task strategies during rehabilitation and RTS training.

Overload of anxiety on postural control impairments in chronic stroke survivors: The role of external focus and cognitive task on the automaticity of postural control

Background

Despite the high prevalence of anxiety among chronic stroke survivors and evidence of its negative effects on postural control in healthy subjects, it is unclear whether anxiety also affects postural control in these patients. Recent evidence of improved postural control of healthy subjects by distracting the attention using an external focus (EF) or cognitive task, raises the question of whether similar benefits would be observed in stroke survivors. Thus, the current study aimed to investigate the effects of anxiety and distracting the attention on postural control of chronic stroke survivors in terms of both postural sway measures and neuromuscular regulation.

Methods

Postural sway measures and ankle muscle activity of chronic stroke survivors with the high and low level of anxiety (HA-stroke (n = 17), and LA-stroke (n = 17), respectively) and age-, sex-, height-, and weight-matched healthy subjects (n = 17) were assessed while standing on rigid and foam surfaces under following conditions: baseline, internal focus (IF), EF, simple and hard cognitive tasks (SC and HC, respectively).

Results

Stroke survivors, particularly HA-stroke participants, showed greater postural sway measures (i.e. postural instability) and enhanced co-contraction of ankle muscles (i.e. stiffening of the neuromuscular system) compared with healthy subjects. As opposed to baseline and IF conditions, postural instability and neuromuscular stiffening significantly reduced in EF condition and decreased more in cognitive task conditions, particularly HC condition.

Conclusions

The results suggest that anxiety enhances stroke-induced postural instability promoting improper neuromuscular control of posture with stiffening strategy, which can be alleviated by EF and cognitive tasks.

Music Restores Propriospinal Excitation During Stroke Locomotion

Music-based therapy for rehabilitation induces neuromodulation at the brain level and improves the functional recovery. In line with this, musical rhythmicity improves post-stroke gait. Moreover, an external distractor also helps stroke patients to improve locomotion. We raised the question whether music with irregular tempo (arrhythmic music), and its possible influence on attention would induce neuromodulation and improve the post-stroke gait. We tested music-induced neuromodulation at the level of a propriospinal reflex, known to be particularly involved in the control of stabilized locomotion; after stroke, the reflex is enhanced on the hemiparetic side. The study was conducted in 12 post-stroke patients and 12 controls. Quadriceps EMG was conditioned by electrical stimulation of the common peroneal nerve, which produces a biphasic facilitation on EMG, reflecting the level of activity of the propriospinal reflex between ankle dorsiflexors and quadriceps (CPQ reflex). The CPQ reflex was tested during treadmill locomotion at the preferred speed of each individual, in 3 conditions randomly alternated: without music vs. 2 arrhythmic music tracks, including a pleasant melody and unpleasant aleatory electronic sounds (AES); biomechanical and physiological parameters were also investigated. The CPQ reflex was significantly larger in patients during walking without sound, compared to controls. During walking with music, irrespective of the theme, there was no more difference between groups. In controls, music had no influence on the size of CPQ reflex. In patients, CPQ reflex was significantly larger during walking without sound than when listening to the melody or AES. No significant differences have been revealed concerning the biomechanical and the physiological parameters in both groups. Arrhythmic music listening modulates the spinal excitability during post-stroke walking, restoring the CPQ reflex activity to normality. The plasticity was not accompanied by any clear improvement of gait parameters, but the patients reported to prefer walking with music than without. The role of music as external focus of attention is discussed. This study has shown that music can modulate propriospinal neural network particularly involved in the gait control during the first training session. It is speculated that repetition may help to consolidate plasticity and would contribute to gait recovery after stroke.