Synergy analysis as a tool to design and assess an effective stroke rehabilitation

Urra, Oiane; Casals, Alı́cia; Jané, Raimon

doi:10.1109/embc.2014.6944389

Cited by 9 publications

(5 citation statements)

References 20 publications

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“…Consequently, inappropriate muscle coordination [5] results in poor motor performance of the affected UL [17][18][19]. Due to their potential to convey information on the neurophysiology of the altered nervous system and subsequent motor impairment, different muscle synergy features have been proposed as quantitative biomarkers for UL motor function in stroke [20][21][22][23][24][25].…”

Section: Introductionmentioning

confidence: 99%

Functional synergy recruitment index as a reliable biomarker of motor function and recovery in chronic stroke patients

Irastorza-Landa

García-Cossio²,

Sarasola-Sanz

et al. 2021

J. Neural Eng.

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Objective. Stroke affects the expression of muscle synergies underlying motor control, most notably in patients with poorer motor function. The majority of studies on muscle synergies have conventionally approached this analysis by assuming alterations in the inner structures of synergies after stroke. Although different synergy-based features based on this assumption have to some extent described pathological mechanisms in post-stroke neuromuscular control, a biomarker that reliably reflects motor function and recovery is still missing. Approach. Based on the theory of muscle synergies, we alternatively hypothesize that functional synergy structures are physically preserved and measure the temporal correlation between the recruitment profiles of healthy modules by paretic and healthy muscles, a feature hereafter reported as the FSRI. We measured clinical scores and extracted the muscle synergies of both ULs of 18 chronic stroke survivors from the electromyographic activity of 8 muscles during bilateral movements before and after 4 weeks of non-invasive BMI controlled robot therapy and physiotherapy. We computed the FSRI as well as features quantifying inter-limb structural differences and evaluated the correlation of these synergy-based measures with clinical scores. Main results. Correlation analysis revealed weak relationships between conventional features describing inter-limb synergy structural differences and motor function. In contrast, FSRI values during specific or combined movement data significantly correlated with UL motor function and recovery scores. Additionally, we observed that BMI-based training with contingent positive proprioceptive feedback led to improved FSRI values during the specific trained finger extension movement. Significance. We demonstrated that FSRI can be used as a reliable physiological biomarker of motor function and recovery in stroke, which can be targeted via BMI-based proprioceptive therapies and adjuvant physiotherapy to boost effective rehabilitation. Abbreviations and acronymsFSRI functional synergy recruitment index BMI brain-machine interface UL upper limb EMG electromyography FMA Fugl-Meyer assessment MAS modified Ashworth scale VAF variance accounted for nCC normalized correlation coefficient

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Section: Introductionmentioning

confidence: 99%

Functional synergy recruitment index as a reliable biomarker of motor function and recovery in chronic stroke patients

Irastorza-Landa

García-Cossio²,

Sarasola-Sanz

et al. 2021

J. Neural Eng.

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“…Although a number of authors have investigated the neurological effects of VF [11,12], to our best knowledge the impact of VF in the control structure has not been addressed yet. In a preliminary study conducted on two simple upper-limb movements, we demonstrated that VF enhances the inter-limb similarity of the control structure [13]. Here, we have extended such study to the analysis of a complete upper-limb rehabilitation routine comprised of 12 movements.…”

Section: Introductionmentioning

confidence: 79%

The impact of visual feedback on the motor control of the upper-limb

Urra

Casals

Jané

2015

2015 37th Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC)

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Abstract-Stroke is a leading cause of adult disability with upper-limb hemiparesis being one of the most frequent consequences. Given that stroke only affects the paretic arm's control structure (the set of synergies and activation vectors needed to perform a movement), we propose that the control structure of the non-affected arm can serve as a physiological reference to rehabilitate the paretic arm. However, it is unclear how rehabilitation can effectively tune the control structure of a patient. The use of Visual Feedback (VF) is recommended to boost stroke rehabilitation, as it is able to positively modify neural mechanisms and improve motor performance. Thus, in this study we investigate whether VF can effectively modify the control structure of the upper-limb. We asked six neurologically intact subjects to perform a complete upper-limb rehabilitation routine comprised of 12 movements in absence and presence of VF. Our results indicate that VF significantly increases interlimb similarity both in terms of synergies and activation coefficients. However, the magnitude of improvement depended upon each subject. In general, VF brings the control structure of the nondominant side closer to the control structure of dominant side, suggesting that VF modifies the control structure towards more optimized motor patterns. This is especially interesting because stroke mainly affects the activation coefficients of patients and because it has been shown that the control of the affected side resembles that of the nondominant side. In conclusion, VF may enhance motor performance by effectively tuning the control-structure. Notably, this finding offers new insights to design improved stroke rehabilitation.

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“…Studies have shown that muscle synergies were robust across healthy subjects (32–34). Thus, we adopted the synergy extracted from dominant arms of the control group as an efficient baseline of synergy (54, 55) and compared synergy of the affected arm in patients to the baseline synergy. In our study, synergy baseline extracted from healthy control group presented similar muscle activations with previous studies (28, 32).…”

Section: Discussionmentioning

confidence: 99%

Evaluation of Functional Correlation of Task-Specific Muscle Synergies with Motor Performance in Patients Poststroke

Cheng

Niu

et al. 2017

Front. Neurol.

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The central nervous system produces movements by activating specifically programmed muscle synergies that are also altered with injuries in the brain, such as stroke. In this study, we hypothesize that there exists a positive correlation between task-specific muscle synergy and motor functions at joint and task levels in patients following stroke. The purpose here is to define and evaluate neurophysiological metrics based on task-specific muscle synergy for assessing motor functions in patients. A patient group of 10 subjects suffering from stroke and a control group of nine age-matched healthy subjects were recruited to participate in this study. Electromyography (EMG) signals and movement kinematics were recorded in patients and control subjects while performing arm reaching tasks. Muscle synergies of individual patients were extracted off-line from EMG records of each patient, and a baseline pattern of muscle synergy was obtained from the pooled EMG data of all nine control subjects. Peak velocities and movement durations of each reaching movement were computed from measured kinematics. Similarity indices of matching components to those of the baseline synergy were defined by synergy vectors and time profiles, respectively, as well as by a combined similarity of vector and time profile. Results showed that pathological synergies of patients were altered from the characteristics of baseline synergy with missing components, or varied vector patterns and time profiles. The kinematic performance measured by peak velocities and movement durations was significantly poorer for the patient group than the control group. In patients, all three similarity indices were found to correlate significantly to the kinematics of movements for the reaching tasks. The correlation to the Fugl-Meyer score of arm was the highest with the vector index, the lowest with the time profile index, and in between with the combined index. These findings illustrate that the analysis of task-specific muscle synergy can provide valuable insights into motor deficits for patients following stroke, and the task-specific similarity indices are useful neurophysiological metrics to predict the function of neuromuscular control at the joint and task levels for patients.

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Synergy analysis as a tool to design and assess an effective stroke rehabilitation

Cited by 9 publications

References 20 publications

Functional synergy recruitment index as a reliable biomarker of motor function and recovery in chronic stroke patients

Functional synergy recruitment index as a reliable biomarker of motor function and recovery in chronic stroke patients

The impact of visual feedback on the motor control of the upper-limb

Evaluation of Functional Correlation of Task-Specific Muscle Synergies with Motor Performance in Patients Poststroke

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