Authors: (including presenting author): :
Kam ACY (1), Au KM (2), Sham KPK (1), Choi JYY (1), Wong CKM (1), Chan ASC (1), Chan VYL (1), Choi BYC (1), Chao CYL (1), Leung CYY (1)
Affiliation: :
(1) Physiotherapy Department, Princess Margaret Hospital, (2) Department of Medicine, Princess Margaret Hospital
Keyword 3: :
physiotherapy
Keyword 5: :
motor function
Introduction: :
Transcranial magnetic stimulation is a novel technology that is thought to improve the motor behavior of the paretic arm in stroke survivors by optimizing plastic changes in the cortex when it was given in combination with physical training. Interhemispheric inhibition through transcallosal connections appears to be dysfunctional after stroke. This may result in an excessive inhibitory drive from unaffected motor cortex over its damaged homologous counterpart, with negative consequences on synaptic plasticity for motor recovery. Low-frequency repetitive transcranial magnetic stimulation (rTMS) may help to modulate this imbalanced activity between motor cortices and hence facilitate the motor recovery after stroke.
Objectives: :
To evaluate and compare the effects of low-frequency rTMS on unaffected primary motor cortex followed by physiotherapy task-orientated upper extremity training on motor behavior of the paretic arm among subacute (< 6 months) and chronic (>6 months) stroke survivors and its correlation with age and severity of motor deficit.
Methodology: :
Participants were 92 individuals with unilateral stroke, stratified into subacute (n=45, 32 males and 13 females, mean age 56±11.2 years; mean time post-stroke 106.9±40.9 days) and chronic (n=47, 30 males and 17 females, mean age 58.7±10.9 years, mean time post-stroke 414.3±192.6 days) cohorts that referred for neurological rehabilitation at the Integrated Neurological Rehabilitation Centre of the Princess Margaret Hospital from Jan 2019 to May 2025. All of them received daily application of continuous trains of 1,200 stimuli of rTMS given at a frequency of 1 Hz at an intensity of 100% resting motor threshold for 20 minutes on 10 consecutive weekdays. The stimulation site was the hand area of the primary motor cortex of unaffected hemisphere. Following rTMS application, participants received 30 minutes physiotherapy task-orientated arm training. Motor behavior of the paretic arm was tested by (i) Fugl-Meyer motor assessment of upper extremity (FMA-UE), (ii) Box and Block test (BBT), and (iii) handgrip strength (HGS). Measurements were performed before and after 10 sessions of the treatment program.
Result & Outcome: :
The motor behavior of the paretic arm improved on completion of treatment regime. The subacute group demonstrated a more significant improvement in the FMA-UE score by 4.5±0.2, BBT by 4.6±0.3 and HGS by 2.2±0.5 kgf (all p< 0.001) whereas the corresponding improvement in the chronic group was 1.7±1.1, 0.6±1.0 and 0.1±1.0 respectively after training which did not reach statistically significant. The time post-stroke for starting to receive the rTMS intervention was negatively significant correlated with post-training FMA-UE score (r=-0.230, p= 0.041) and BBT (r=-0.319, p=0.004). No correlation was demonstrated between age, gender or types of strokes versus any of the outcomes. Low-frequency rTMS suppressed the motor cortex excitability in the stimulated unaffected hemisphere to enhance the effect of physiotherapy task-orientated arm training for stroke patients. This combination is more effective in subacute than chronic stroke patients. A negative correlation was demonstrated between the time post-stroke for receiving rTMS intervention toward motor performance outcomes, suggesting that initiating the therapy as soon as possible once the clinical condition is stable could enhance its therapeutic effect.
