Effects of Transcutaneous Electrical Nerve Stimulation on Cognitive Function and Upper Limb Motor Function in People With Chronic Stroke

Effects of Transcutaneous Electrical Nerve Stimulation on Cognitive Function and Upper Limb Motor Function in People With Chronic Stroke

A Randomized Controlled Clinical Trial of Transcutaneous Electrical Nerve Stimulation on Cognitive Function and Upper Limb Motor Function in People With Chronic Stroke

Upper limb impairment is present in more than 85% of people with stroke, which greatly affect the quality of life, social participation, and performance of daily activities of people with stroke. Previous study also revealed that 53.4% of people after stroke experienced cognitive impairment. Different cognitive domains might be affected following stroke, such as attention, memory, language, and orientation, and the problems with memory are often prominent. Yet, there is no effective treatment for the post-stroke cognitive impairment. Transcutaneous electrical nerve stimulation (TENS) applied on thoracic region and transcutaneous vagus nerve stimulation (tVNS) are simple and non-invasive treatment to improve upper limb motor function and cognitive function. However, no existing studies have explored on the effects of TENS and tVNS on cognitive function in people with stroke. Therefore, the purpose of this study is to evaluate the effectiveness of TENS on improving upper limb function and cognitive function in people with chronic stroke. Also, this study will investigate the cortical response of people with stroke during TENS by using EEG power spectrum analysis.

This study aims to investigate the effects of three intervention protocols in people with stroke. The participants in Group A will receive TENS on C6 and T5 level of the spine with upper limb exercises. The participants in Group B will receive tVNS on the cymba conchae of left outer ear with upper limb exercises. The participants in Group C will receive placebo tVNS with upper limb exercises.

The participants will be received eighteen 45-minute sessions of intervention, 3 sessions per week for 6 weeks.

The participants will be received eighteen 45-minute sessions of intervention, 3 sessions per week for 6 weeks.

The participants will be received eighteen 45-minute sessions of intervention, 3 sessions per week for 6 weeks.

The participants in Group A will receive TENS (Burst mode, 9 pulses per burst, pulse frequency = 160 Hz, burst frequency = 2 Hz) with upper limb exercises. The electrical stimulation will be generated by the neurostimulator (MH8000P; MEDIHIGHTEC MEDICAL CO., LTD., Taiwan). Two 7.5 × 12.6 cm electrodes will be attached between C6 and T5 level on each side of spinal column and with 2 cm from the spine. Intensity of TENS will be individually selected by the participants according to tolerance levels.

The participants in Group B will receive tVNS (pulse frequency = 25Hz, pulse duration = 0.3 ms) on the cymba conchae of left outer ear with upper limb exercises.The electrical stimulation will be generated by the neurostimulator (MH8000P; MEDIHIGHTEC MEDICAL CO., LTD., Taiwan). Intensity of tVNS will be individually selected by the participants according to tolerance levels. Previous studies showed that it was effective to improve the upper limb motor function in people with stroke and cognitive function in people with mild cognitive function.

The participants in Group C will receive placebo tVNS with upper limb exercises, where the stimulation will be delivered by placebo-TENS device with disconnected electrical circuit.

The Fugl-Meyer Assessment of the Upper Extremity (FMA-UE) assesses the motor control, which included the reflex, synergistic and isolated movements and coordination of the upper extremity. It is a 3-point ordinal scale with 33 items and the total score ranges from 0 to 66. In this scale, "0" represents "cannot perform", "1" represents "performs partially" and "2" represents "performs fully". The higher score indicates better motor control of the upper extremity. The FMA-UE has an excellent inter-rater reliability (ICC = 0.98) in people with stroke.

The Fugl-Meyer Assessment of the Upper Extremity (FMA-UE) assesses the motor control, which included the reflex, synergistic and isolated movements and coordination of the upper extremity. It is a 3-point ordinal scale with 33 items and the total score ranges from 0 to 66. In this scale, "0" represents "cannot perform", "1" represents "performs partially" and "2" represents "performs fully". The higher score indicates better motor control of the upper extremity. The FMA-UE has an excellent inter-rater reliability (ICC = 0.98) in people with stroke.

The Fugl-Meyer Assessment of the Upper Extremity (FMA-UE) assesses the motor control, which included the reflex, synergistic and isolated movements and coordination of the upper extremity. It is a 3-point ordinal scale with 33 items and the total score ranges from 0 to 66. In this scale, "0" represents "cannot perform", "1" represents "performs partially" and "2" represents "performs fully". The higher score indicates better motor control of the upper extremity. The FMA-UE has an excellent inter-rater reliability (ICC = 0.98) in people with stroke.

The Fugl-Meyer Assessment of the Upper Extremity (FMA-UE) assesses the motor control, which included the reflex, synergistic and isolated movements and coordination of the upper extremity. It is a 3-point ordinal scale with 33 items and the total score ranges from 0 to 66. In this scale, "0" represents "cannot perform", "1" represents "performs partially" and "2" represents "performs fully". The higher score indicates better motor control of the upper extremity. The FMA-UE has an excellent inter-rater reliability (ICC = 0.98) in people with stroke.

The Wolf Motor Function Test (WMFT) evaluates the motor ability of upper extremity through timed and functional tasks. It consists of 17 tasks which is rated by 6-point scale which ranges from 0 (no attempt made to use the more affected upper extremity) to 5 (movement appears to be normal). The time for completing each functional task is also recorded, with a maximum of 120 seconds allow for each task. The higher score represents the better functioning level of upper extremity, Excellent test-retest reliability (ICC = 0.92 - 0.99) has been demonstrated in people with stroke.

The Wolf Motor Function Test (WMFT) evaluates the motor ability of upper extremity through timed and functional tasks. It consists of 17 tasks which is rated by 6-point scale which ranges from 0 (no attempt made to use the more affected upper extremity) to 5 (movement appears to be normal). The time for completing each functional task is also recorded, with a maximum of 120 seconds allow for each task. The higher score represents the better functioning level of upper extremity, Excellent test-retest reliability (ICC = 0.92 - 0.99) has been demonstrated in people with stroke.

The Wolf Motor Function Test (WMFT) evaluates the motor ability of upper extremity through timed and functional tasks. It consists of 17 tasks which is rated by 6-point scale which ranges from 0 (no attempt made to use the more affected upper extremity) to 5 (movement appears to be normal). The time for completing each functional task is also recorded, with a maximum of 120 seconds allow for each task. The higher score represents the better functioning level of upper extremity, Excellent test-retest reliability (ICC = 0.92 - 0.99) has been demonstrated in people with stroke.

The Wolf Motor Function Test (WMFT) evaluates the motor ability of upper extremity through timed and functional tasks. It consists of 17 tasks which is rated by 6-point scale which ranges from 0 (no attempt made to use the more affected upper extremity) to 5 (movement appears to be normal). The time for completing each functional task is also recorded, with a maximum of 120 seconds allow for each task. The higher score represents the better functioning level of upper extremity, Excellent test-retest reliability (ICC = 0.92 - 0.99) has been demonstrated in people with stroke.

A hand-held dynamometer (Model 01165; Lafayette Instrument, Indiana, USA) will be used to measure the muscle force generated by biceps brachii and triceps brachii muscles of affected and unaffected sides. The participant will be instructed to perform isometric contraction and resistance will be applied by the examiner to avoid movement of the arm during the measurement. Two trials will be performed for each muscle group and the mean force of two trials will be recorded.

A hand-held dynamometer (Model 01165; Lafayette Instrument, Indiana, USA) will be used to measure the muscle force generated by biceps brachii and triceps brachii muscles of affected and unaffected sides. The participant will be instructed to perform isometric contraction and resistance will be applied by the examiner to avoid movement of the arm during the measurement. Two trials will be performed for each muscle group and the mean force of two trials will be recorded.

A hand-held dynamometer (Model 01165; Lafayette Instrument, Indiana, USA) will be used to measure the muscle force generated by biceps brachii and triceps brachii muscles of affected and unaffected sides. The participant will be instructed to perform isometric contraction and resistance will be applied by the examiner to avoid movement of the arm during the measurement. Two trials will be performed for each muscle group and the mean force of two trials will be recorded.

A hand-held dynamometer (Model 01165; Lafayette Instrument, Indiana, USA) will be used to measure the muscle force generated by biceps brachii and triceps brachii muscles of affected and unaffected sides. The participant will be instructed to perform isometric contraction and resistance will be applied by the examiner to avoid movement of the arm during the measurement. Two trials will be performed for each muscle group and the mean force of two trials will be recorded.

The muscle stiffness of biceps brachii and triceps brachii muscles will be quantified by MyotonPRO device (Myoton AS, Tallinn, Estonia). The MyotonPRO device will be placed perpendicularly to the skin surface and apply mechanical impulses on the muscles to generate damped oscillations of the underlying tissue. The biceps brachii measurements will be performed at the long head of the muscle in the middle of the arm. The triceps brachii measurements will be performed at the medial head of the muscle in the middle of the arm. Muscle stiffness will be described as newton-meter (N/m), where the higher value indicates the higher stiffness of the tissue.

The muscle stiffness of biceps brachii and triceps brachii muscles will be quantified by MyotonPRO device (Myoton AS, Tallinn, Estonia). The MyotonPRO device will be placed perpendicularly to the skin surface and apply mechanical impulses on the muscles to generate damped oscillations of the underlying tissue. The biceps brachii measurements will be performed at the long head of the muscle in the middle of the arm. The triceps brachii measurements will be performed at the medial head of the muscle in the middle of the arm. Muscle stiffness will be described as newton-meter (N/m), where the higher value indicates the higher stiffness of the tissue.

The muscle stiffness of biceps brachii and triceps brachii muscles will be quantified by MyotonPRO device (Myoton AS, Tallinn, Estonia). The MyotonPRO device will be placed perpendicularly to the skin surface and apply mechanical impulses on the muscles to generate damped oscillations of the underlying tissue. The biceps brachii measurements will be performed at the long head of the muscle in the middle of the arm. The triceps brachii measurements will be performed at the medial head of the muscle in the middle of the arm. Muscle stiffness will be described as newton-meter (N/m), where the higher value indicates the higher stiffness of the tissue.

The muscle stiffness of biceps brachii and triceps brachii muscles will be quantified by MyotonPRO device (Myoton AS, Tallinn, Estonia). The MyotonPRO device will be placed perpendicularly to the skin surface and apply mechanical impulses on the muscles to generate damped oscillations of the underlying tissue. The biceps brachii measurements will be performed at the long head of the muscle in the middle of the arm. The triceps brachii measurements will be performed at the medial head of the muscle in the middle of the arm. Muscle stiffness will be described as newton-meter (N/m), where the higher value indicates the higher stiffness of the tissue.

The Rivermead Behavioural Memory Test - Third edition (RBMT-3) examines the everyday memory function with 14 subtests, including the assessment for visual, verbal, recall, recognition, immediate, and delayed memory. The scaled score of each subtest and total scaled score will be computed by converting raw scores based on different age group. Higher scaled score indicates better memory function. The RBMT-3 has demonstrated excellent inter-rater reliability (ICC = 0.997) and intra-rater reliability (ICC = 0.924) and good internal consistency (Cronbach's alpha = 0.643 - 0.832) in people with dementia, mild cognitive impairment and healthy older adults.

The Rivermead Behavioural Memory Test - Third edition (RBMT-3) examines the everyday memory function with 14 subtests, including the assessment for visual, verbal, recall, recognition, immediate, and delayed memory. The scaled score of each subtest and total scaled score will be computed by converting raw scores based on different age group. Higher scaled score indicates better memory function. The RBMT-3 has demonstrated excellent inter-rater reliability (ICC = 0.997) and intra-rater reliability (ICC = 0.924) and good internal consistency (Cronbach's alpha = 0.643 - 0.832) in people with dementia, mild cognitive impairment and healthy older adults.

The Rivermead Behavioural Memory Test - Third edition (RBMT-3) examines the everyday memory function with 14 subtests, including the assessment for visual, verbal, recall, recognition, immediate, and delayed memory. The scaled score of each subtest and total scaled score will be computed by converting raw scores based on different age group. Higher scaled score indicates better memory function. The RBMT-3 has demonstrated excellent inter-rater reliability (ICC = 0.997) and intra-rater reliability (ICC = 0.924) and good internal consistency (Cronbach's alpha = 0.643 - 0.832) in people with dementia, mild cognitive impairment and healthy older adults.

The Rivermead Behavioural Memory Test - Third edition (RBMT-3) examines the everyday memory function with 14 subtests, including the assessment for visual, verbal, recall, recognition, immediate, and delayed memory. The scaled score of each subtest and total scaled score will be computed by converting raw scores based on different age group. Higher scaled score indicates better memory function. The RBMT-3 has demonstrated excellent inter-rater reliability (ICC = 0.997) and intra-rater reliability (ICC = 0.924) and good internal consistency (Cronbach's alpha = 0.643 - 0.832) in people with dementia, mild cognitive impairment and healthy older adults.

The Digit Span Test (DST) consists of two parts to measure the verbal short-term memory and working memory of an individual, which are digit span forwards and digit span backwards. The participants are presented with a series of numbers. In the digit span forward (DSF), they are required to repeat the numbers in forward order. In the digit span backward (DSB), they are asked to repeat the numbers in reverse order. The length of digits in each string increases from 3 to 9 in DSF and from 2 to 8 in DSB. Two trials are presented at each length. The test is interrupted when participant failed to either trial at equal digit length. If the participants correctly recall the sequence in either first and second trial, 1 point will be scored. The total score of DSF and DSB are 16 and 14 respectively. The intra-rater reliability of DSF and DSB are 0.891 and 0.598 respectively in older adults with neurocognitive disorder.

The Digit Span Test (DST) consists of two parts to measure the verbal short-term memory and working memory of an individual, which are digit span forwards and digit span backwards. The participants are presented with a series of numbers. In the digit span forward (DSF), they are required to repeat the numbers in forward order. In the digit span backward (DSB), they are asked to repeat the numbers in reverse order. The length of digits in each string increases from 3 to 9 in DSF and from 2 to 8 in DSB. Two trials are presented at each length. The test is interrupted when participant failed to either trial at equal digit length. If the participants correctly recall the sequence in either first and second trial, 1 point will be scored. The total score of DSF and DSB are 16 and 14 respectively. The intra-rater reliability of DSF and DSB are 0.891 and 0.598 respectively in older adults with neurocognitive disorder.

The Digit Span Test (DST) consists of two parts to measure the verbal short-term memory and working memory of an individual, which are digit span forwards and digit span backwards. The participants are presented with a series of numbers. In the digit span forward (DSF), they are required to repeat the numbers in forward order. In the digit span backward (DSB), they are asked to repeat the numbers in reverse order. The length of digits in each string increases from 3 to 9 in DSF and from 2 to 8 in DSB. Two trials are presented at each length. The test is interrupted when participant failed to either trial at equal digit length. If the participants correctly recall the sequence in either first and second trial, 1 point will be scored. The total score of DSF and DSB are 16 and 14 respectively. The intra-rater reliability of DSF and DSB are 0.891 and 0.598 respectively in older adults with neurocognitive disorder.

The Digit Span Test (DST) consists of two parts to measure the verbal short-term memory and working memory of an individual, which are digit span forwards and digit span backwards. The participants are presented with a series of numbers. In the digit span forward (DSF), they are required to repeat the numbers in forward order. In the digit span backward (DSB), they are asked to repeat the numbers in reverse order. The length of digits in each string increases from 3 to 9 in DSF and from 2 to 8 in DSB. Two trials are presented at each length. The test is interrupted when participant failed to either trial at equal digit length. If the participants correctly recall the sequence in either first and second trial, 1 point will be scored. The total score of DSF and DSB are 16 and 14 respectively. The intra-rater reliability of DSF and DSB are 0.891 and 0.598 respectively in older adults with neurocognitive disorder.

The Montreal Cognitive Assessment (MoCA) is a screening tool to detect cognitive impairment of an individual with a total score of 30. The MoCA assesses different cognitive domains, including executive functioning, immediate and delayed memory, visuospatial abilities, attention, working memory, language, and orientation to time and place. It can identify dementia from controls with a sensitivity of 92.3% and specificity of 91.8% with a cut-off score of 22.

The Montreal Cognitive Assessment (MoCA) is a screening tool to detect cognitive impairment of an individual with a total score of 30. The MoCA assesses different cognitive domains, including executive functioning, immediate and delayed memory, visuospatial abilities, attention, working memory, language, and orientation to time and place. It can identify dementia from controls with a sensitivity of 92.3% and specificity of 91.8% with a cut-off score of 22.

The Montreal Cognitive Assessment (MoCA) is a screening tool to detect cognitive impairment of an individual with a total score of 30. The MoCA assesses different cognitive domains, including executive functioning, immediate and delayed memory, visuospatial abilities, attention, working memory, language, and orientation to time and place. It can identify dementia from controls with a sensitivity of 92.3% and specificity of 91.8% with a cut-off score of 22.

The Montreal Cognitive Assessment (MoCA) is a screening tool to detect cognitive impairment of an individual with a total score of 30. The MoCA assesses different cognitive domains, including executive functioning, immediate and delayed memory, visuospatial abilities, attention, working memory, language, and orientation to time and place. It can identify dementia from controls with a sensitivity of 92.3% and specificity of 91.8% with a cut-off score of 22.

Trail Making Test (TMT) can assess the attention and cognitive flexibility of individuals. The test is divided into part A and part B. In part A, the circle is numbered (i.e., 1 to 25). The subjects should draw lines in numeric order of the listed circle. In part B, the circles include both numbers (i.e., 1 to 13) and words (i.e., A to L). The subjects should draw the lines in a specific sequence between number and word (i.e., 1 to A to 2 to B etc.). A shorter time recorded in the test indicated the better performance. The test-retest reliability has been tested in people with stroke (ICC = 0.94 and 0.86 for Part A and Part B, respectively).

Trail Making Test (TMT) can assess the attention and cognitive flexibility of individuals. The test is divided into part A and part B. In part A, the circle is numbered (i.e., 1 to 25). The subjects should draw lines in numeric order of the listed circle. In part B, the circles include both numbers (i.e., 1 to 13) and words (i.e., A to L). The subjects should draw the lines in a specific sequence between number and word (i.e., 1 to A to 2 to B etc.). A shorter time recorded in the test indicated the better performance. The test-retest reliability has been tested in people with stroke (ICC = 0.94 and 0.86 for Part A and Part B, respectively).

Trail Making Test (TMT) can assess the attention and cognitive flexibility of individuals. The test is divided into part A and part B. In part A, the circle is numbered (i.e., 1 to 25). The subjects should draw lines in numeric order of the listed circle. In part B, the circles include both numbers (i.e., 1 to 13) and words (i.e., A to L). The subjects should draw the lines in a specific sequence between number and word (i.e., 1 to A to 2 to B etc.). A shorter time recorded in the test indicated the better performance. The test-retest reliability has been tested in people with stroke (ICC = 0.94 and 0.86 for Part A and Part B, respectively).

Trail Making Test (TMT) can assess the attention and cognitive flexibility of individuals. The test is divided into part A and part B. In part A, the circle is numbered (i.e., 1 to 25). The subjects should draw lines in numeric order of the listed circle. In part B, the circles include both numbers (i.e., 1 to 13) and words (i.e., A to L). The subjects should draw the lines in a specific sequence between number and word (i.e., 1 to A to 2 to B etc.). A shorter time recorded in the test indicated the better performance. The test-retest reliability has been tested in people with stroke (ICC = 0.94 and 0.86 for Part A and Part B, respectively).

The 23-item Oxford Participation and Activities Questionnaire (Ox-PAQ) evaluates participation and activity levels based on the three domains of routine activities, social engagement, and emotional well-being. Each item is measured on a 5-point Likert scale (0 = never; 1 = rarely; 2 = sometimes; 3 = often; 4 = always). The higher scores represent greater difficulties with participation and activities. Good to excellent internal consistency (Cronbach's α = 0.81 - 0.96) and test-retest reliability (ICC = 0.83 - 0.96) have been shown for this instrument in people with motor neuron disease, multiple sclerosis, and Parkinson's disease.

The 23-item Oxford Participation and Activities Questionnaire (Ox-PAQ) evaluates participation and activity levels based on the three domains of routine activities, social engagement, and emotional well-being. Each item is measured on a 5-point Likert scale (0 = never; 1 = rarely; 2 = sometimes; 3 = often; 4 = always). The higher scores represent greater difficulties with participation and activities. Good to excellent internal consistency (Cronbach's α = 0.81 - 0.96) and test-retest reliability (ICC = 0.83 - 0.96) have been shown for this instrument in people with motor neuron disease, multiple sclerosis, and Parkinson's disease.

The 23-item Oxford Participation and Activities Questionnaire (Ox-PAQ) evaluates participation and activity levels based on the three domains of routine activities, social engagement, and emotional well-being. Each item is measured on a 5-point Likert scale (0 = never; 1 = rarely; 2 = sometimes; 3 = often; 4 = always). The higher scores represent greater difficulties with participation and activities. Good to excellent internal consistency (Cronbach's α = 0.81 - 0.96) and test-retest reliability (ICC = 0.83 - 0.96) have been shown for this instrument in people with motor neuron disease, multiple sclerosis, and Parkinson's disease.

The 23-item Oxford Participation and Activities Questionnaire (Ox-PAQ) evaluates participation and activity levels based on the three domains of routine activities, social engagement, and emotional well-being. Each item is measured on a 5-point Likert scale (0 = never; 1 = rarely; 2 = sometimes; 3 = often; 4 = always). The higher scores represent greater difficulties with participation and activities. Good to excellent internal consistency (Cronbach's α = 0.81 - 0.96) and test-retest reliability (ICC = 0.83 - 0.96) have been shown for this instrument in people with motor neuron disease, multiple sclerosis, and Parkinson's disease.

The 12-item Short-Form Survey (second version) (SF-12v2) will be used to measure the health-related quality of life of individuals. This instrument contains eight domains: physical functioning, role physical, bodily pain, general health, vitality, social functioning, emotional role, and mental health. The total score ranges from 0 to 100, with a higher score indicating better quality of life. It has good internal consistency (Cronbach's alpha = 0.48 - 0.81) and test-retest reliability (ICC = 0.67 - 0.82) in healthy adults.

The 12-item Short-Form Survey (second version) (SF-12v2) will be used to measure the health-related quality of life of individuals. This instrument contains eight domains: physical functioning, role physical, bodily pain, general health, vitality, social functioning, emotional role, and mental health. The total score ranges from 0 to 100, with a higher score indicating better quality of life. It has good internal consistency (Cronbach's alpha = 0.48 - 0.81) and test-retest reliability (ICC = 0.67 - 0.82) in healthy adults.

The 12-item Short-Form Survey (second version) (SF-12v2) will be used to measure the health-related quality of life of individuals. This instrument contains eight domains: physical functioning, role physical, bodily pain, general health, vitality, social functioning, emotional role, and mental health. The total score ranges from 0 to 100, with a higher score indicating better quality of life. It has good internal consistency (Cronbach's alpha = 0.48 - 0.81) and test-retest reliability (ICC = 0.67 - 0.82) in healthy adults.

The 12-item Short-Form Survey (second version) (SF-12v2) will be used to measure the health-related quality of life of individuals. This instrument contains eight domains: physical functioning, role physical, bodily pain, general health, vitality, social functioning, emotional role, and mental health. The total score ranges from 0 to 100, with a higher score indicating better quality of life. It has good internal consistency (Cronbach's alpha = 0.48 - 0.81) and test-retest reliability (ICC = 0.67 - 0.82) in healthy adults.

The Arm Activity Measure (ArmA) is a 20-item questionnaire to assess the difficulties in passive and active upper limb tasks, where section A evaluates the passive function and section B evaluates the active function. It uses a 5-point Likert scale, ranging from 0 (no difficulty) to 4 (unable to do the task). The total score of section A and B are 32 and 52 respectively [59]. The higher score in ArmA indicates more difficulties experienced in activities when using upper limb. Good internal consistency (Cronbach's alpha = 0.85 - 0.96) has been shown in people with upper limb paresis.

The Arm Activity Measure (ArmA) is a 20-item questionnaire to assess the difficulties in passive and active upper limb tasks, where section A evaluates the passive function and section B evaluates the active function. It uses a 5-point Likert scale, ranging from 0 (no difficulty) to 4 (unable to do the task). The total score of section A and B are 32 and 52 respectively [59]. The higher score in ArmA indicates more difficulties experienced in activities when using upper limb. Good internal consistency (Cronbach's alpha = 0.85 - 0.96) has been shown in people with upper limb paresis.

The Arm Activity Measure (ArmA) is a 20-item questionnaire to assess the difficulties in passive and active upper limb tasks, where section A evaluates the passive function and section B evaluates the active function. It uses a 5-point Likert scale, ranging from 0 (no difficulty) to 4 (unable to do the task). The total score of section A and B are 32 and 52 respectively [59]. The higher score in ArmA indicates more difficulties experienced in activities when using upper limb. Good internal consistency (Cronbach's alpha = 0.85 - 0.96) has been shown in people with upper limb paresis.

The Arm Activity Measure (ArmA) is a 20-item questionnaire to assess the difficulties in passive and active upper limb tasks, where section A evaluates the passive function and section B evaluates the active function. It uses a 5-point Likert scale, ranging from 0 (no difficulty) to 4 (unable to do the task). The total score of section A and B are 32 and 52 respectively [59]. The higher score in ArmA indicates more difficulties experienced in activities when using upper limb. Good internal consistency (Cronbach's alpha = 0.85 - 0.96) has been shown in people with upper limb paresis.

Inclusion Criteria: aged between 50 and 80; have suffered from a single stroke at least 1 year; had volitional control of the non-paretic arm and at least minimal antigravity movement in the paretic shoulder; scored 7 or above in the Abbreviated Mental Test. Exclusion Criteria: have cardiac pacemaker or cochlear implant; have other neurological diseases; are taking medication that may affect measured outcomes; have skin lesions, infection, or inflammation near selected position; are participating in other drug/treatment programs.

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