Imaging of 3D Innervation Zone Distribution in Spastic Muscles From High-density Surface EMG Recordings

Inclusion Criteria:

- a history of not more than one stroke which occurred at least 6 months prior to study
enrollment;

- elbow flexor spasticity rated at 2 or 3 on Modified Ashworth scale (MAS);

- receiving repeated botulinum toxin injection every 3-4 months;

- absence of excessive pain in the paretic upper limb;

- capacity to provide informed consent, with Mini‐Mental State Examination (MMSE) must
be 25 or higher;

The following modified Ashworth scale (MAS) will be used for spasticity assessment:

0 -No increase in muscle tone;

1 -Slight increase in muscle tone, manifested by a catch and release or by minimal
resistance at the end of the range of motion when the affected part(s) is moved in flexion
or extension;

1+ -Slight increase in muscle tone, manifested by a catch, followed by minimal resistance
throughout the remainder (less than half) of the ROM; 2 -More marked increase in muscle
tone through most of the ROM, but affected part(s) easily moved; 3 -Considerable increase
in muscle tone, passive movement difficult; 4 -Affected part(s) rigid in flexion or
extension.

Exclusion Criteria:

- recent botulinum toxin injection < 4 months;

- recent changes in antispastic medications <3 weeks (i.e., the antispastic medication
regime is not stable;

- Changes in antispastic medications (such as baclofen, tizanidine, dantrolene etc)
during the followup research visits. (NOTE: it is clinically rare for patients who
receive repeated injections to change their antispastic medications);

- history of spinal cord injury or traumatic brain damage;

- history of serious medical illness such as cardiovascular or pulmonary complications;

- any condition that, in the judgment of a physician, would prevent the person from
participating.