Examining the equivalence between imagery and execution within the spatial domain – Does motor imagery account for signal-dependent noise?

Abstract Motor imagery is suggested to be functionally equivalent to physical execution as they each utilise a common neural representation. The present study examined whether motor imagery correspondingly reflects the spatial characteristics of physically executed movements, including the signal-dependent noise that typically manifests in more variable end locations (as indicated by effective target width; We). Participants executed or imagined a single, upper-limb target-directed aim in the horizontal medio-lateral direction. The start and end of the imagined movements were indexed by the lifting and lowering of the limb over the home position, respectively. Following each imagined movement, participants had to additionally estimate their imagined end location relative to the target. All the movements had to be completed at a pre-specified criterion time (400 ms, 600 ms, 800 ms). The results indicated that the We increased following a decrease in movement time for execution, but not imagery. Moreover, the total error of imagined movements was greater than the actual error of executed movements. While motor imagery may comprise a neural representation that also contributes to the execution of movements, it is unable to closely reflect the random sources of variability. This limitation of motor imagery may be attributed to the comparatively limited efferent motor signals.

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Upper-limb Rehabilitation Robot Based on Motor Imagery EEG

ROBOT ◽

10.3724/sp.j.1218.2011.00307 ◽

2011 ◽

Vol 33 (3) ◽

pp. 307-313 ◽

Cited By ~ 5

Author(s):

Baoguo XU ◽

Si PENG ◽

Aiguo SONG

Keyword(s):

Motor Imagery ◽

Upper Limb ◽

Rehabilitation Robot ◽

Upper Limb Rehabilitation ◽

Limb Rehabilitation

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Muscle-specific movement-phase-dependent modulation of corticospinal excitability during upper-limb motor execution and motor imagery combined with virtual action observation

Neuroscience Letters ◽

10.1016/j.neulet.2021.135907 ◽

2021 ◽

pp. 135907

Author(s):

Yoshiyuki Suzuki ◽

Naotsugu Kaneko ◽

Atsushi Sasaki ◽

Fumiya Tanaka ◽

Kimitaka Nakazawa ◽

...

Keyword(s):

Motor Imagery ◽

Upper Limb ◽

Action Observation ◽

Corticospinal Excitability ◽

Motor Execution

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FRI0617-HPR GRADED MOTOR IMAGERY IN POSTTRAUMATIC STIFFNESS OF THE ELBOW: A PILOT STUDY

Annals of the Rheumatic Diseases ◽

10.1136/annrheumdis-2020-eular.2660 ◽

2020 ◽

Vol 79 (Suppl 1) ◽

pp. 913.2-914

Author(s):

T. Birinci ◽

E. Kaya Mutlu ◽

S. Altun

Keyword(s):

Pilot Study ◽

Motor Imagery ◽

Upper Limb ◽

Exercise Program ◽

Control Group ◽

Elbow Fracture ◽

Stiff Elbow ◽

Limb Fractures ◽

Upper Limb Fractures ◽

Graded Motor Imagery

Background:Elbow fracture is treated either conservatively or surgically followed by a period of immobilization with casting or splinting. A splint used to immobilize upper limbs for many weeks results in changes in both the peripheral musculature and the central nervous system. It is well known that common complaints after upper limb fractures include weakness, pain, and stiffness; therefore, pain management is important in the early stages of the rehabilitation of upper limb fractures.Objectives:This pilot study aimed to investigate the efficacy of graded motor imaginary (GMI) on pain, range of motion (ROM), and function in patients with posttraumatic stiff elbow.Methods:Fourteen patients with posttraumatic stiff elbow (6 women, mean age: 45.42 ± 11.26 years, mean body mass index: 24.29 ± 3.38 kg\m2and mean duration of immobilization: 4.75 ± 1.03 weeks) were randomly allocated to either GMI or control groups. The GMI group received GMI treatment in addition to a structured exercise program, and the control group received a structured exercise program (two days per week for six weeks) (Figure 1). The assessments included pain at rest and during activity using the visual analog scale (VAS), elbow active ROM with a digital goniometer (Baseline Evaluation Instrument, Fabrication Enterprises, Inc., White Plains, NY), and upper extremity functional status using the Disability of the Arm, Shoulder and Hand Questionnaire (DASH). The assessments were performed at baseline and after the 6-week intervention.Figure 1.Graded motor imagery performed with mirror boxResults:After the 6-week intervention, there was a significant increase in elbow flexion-extension ROM and supination-pronation ROM, and improvement in DASH score in both groups (p<0.05). However, improvement in VAS-rest and VAS-activity was significantly higher in the GMI group than the control group (p=0.03 and p=0.01, respectively).Conclusion:A conservative treatment program consisting of GMI treatment in addition to a structured exercise program applied twice a week for 6 weeks, has been found more effective in decreasing pain in the posttraumatic stiff elbow. It could be concluded that GMI is an effective treatment method for elbow fracture in patients with predominant elbow pain.References:[1] Harris JE, Hebert A. Utilization of motor imagery in upper limb rehabilitation: a systematic scoping review. Clin Rehab. 2015:29(11):1092-1107.[2] Opie GM, Evans A, Ridding MC, Semmler JG. Short-term immobilization influences use-dependent cortical plasticity and fine motor performance. Neuroscience. 2016:330:247-256.[3] Birinci T, Razak Ozdincler A, Altun S, Kural C. A structured exercise programme combined with proprioceptive neuromuscular facilitation stretching or static stretching in posttraumatic stiffness of the elbow: a randomized controlled trial. Clin Rehab. 2019:33(2):241-252.Acknowledgments:The present work was supported by the Scientific Research Projects Coordination Unit of Istanbul University-Cerrahpasa (Project No: TDK-2019-33997).Disclosure of Interests:None declared

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Effect of post-stroke spasticity on voluntary movement of the upper limb

Journal of NeuroEngineering and Rehabilitation ◽

10.1186/s12984-021-00876-6 ◽

2021 ◽

Vol 18 (1) ◽

Author(s):

Hadar Lackritz ◽

Yisrael Parmet ◽

Silvi Frenkel-Toledo ◽

Melanie C. Baniña ◽

Nachum Soroker ◽

...

Keyword(s):

Upper Limb ◽

Target Location ◽

Distance Measure ◽

Movement Time ◽

Motor Impairment ◽

Reach To Grasp ◽

Motion Patterns ◽

Post Stroke ◽

The Impact ◽

Elbow Motion

Abstract Background Hemiparesis following stroke is often accompanied by spasticity. Spasticity is one factor among the multiple components of the upper motor neuron syndrome that contributes to movement impairment. However, the specific contribution of spasticity is difficult to isolate and quantify. We propose a new method of quantification and evaluation of the impact of spasticity on the quality of movement following stroke. Methods Spasticity was assessed using the Tonic Stretch Reflex Threshold (TSRT). TSRT was analyzed in relation to stochastic models of motion to quantify the deviation of the hemiparetic upper limb motion from the normal motion patterns during a reaching task. Specifically, we assessed the impact of spasticity in the elbow flexors on reaching motion patterns using two distinct measures of the ‘distance’ between pathological and normal movement, (a) the bidirectional Kullback–Liebler divergence (BKLD) and (b) Hellinger’s distance (HD). These measures differ in their sensitivity to different confounding variables. Motor impairment was assessed clinically by the Fugl-Meyer assessment scale for the upper extremity (FMA-UE). Forty-two first-event stroke patients in the subacute phase and 13 healthy controls of similar age participated in the study. Elbow motion was analyzed in the context of repeated reach-to-grasp movements towards four differently located targets. Log-BKLD and HD along with movement time, final elbow extension angle, mean elbow velocity, peak elbow velocity, and the number of velocity peaks of the elbow motion were computed. Results Upper limb kinematics in patients with lower FMA-UE scores (greater impairment) showed greater deviation from normality when the distance between impaired and normal elbow motion was analyzed either with the BKLD or HD measures. The severity of spasticity, reflected by the TSRT, was related to the distance between impaired and normal elbow motion analyzed with either distance measure. Mean elbow velocity differed between targets, however HD was not sensitive to target location. This may point at effects of spasticity on motion quality that go beyond effects on velocity. Conclusions The two methods for analyzing pathological movement post-stroke provide new options for studying the relationship between spasticity and movement quality under different spatiotemporal constraints.

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