Shear wave elastography of the brachioradialis spastic muscle and its correlations with biceps brachialis and clinical scales.

BACKGROUND: Shear wave elastography technique estimates biological tissue shear elastic modulus (µ[kPa]), which can be used as an objective, muscle-specific indicator of stiffness increase caused by spasticity. We measured both the brachioradialis and biceps brachialis µ in hemiparetic post-stroke patients (n = 11). The spastic arm was compared with the supposedly non-affected contralateral limb and correlated with Fugl-Meyer Assessment and Modified Ashworth Scales. METHODS: Shear elastic modulus was estimated using an Aixplorer V.9 ultrasound device with the elbow at full extension. Average shear elastic modulus t-test, effect sizes, correlation matrix, spider plots and factor analysis were used to check for differences between spastic and nonspastic sides and explore relationships among the variables. FINDINGS: Spastic brachioradialis µ (22.54 ± 11.59 kPa) and biceps brachialis (26.86 ± 12.07 kPa) were significantly greater than the non-spastic counterparts (13.13 ± 2.81 kPa, p = 0.031, ηp2 = 0.3846 for brachioradialis and 15.25 ± 5.00 kPa, p = 0.007, ηp2 = 0.5345 for biceps brachialis). Significant correlations were observed between the spastic brachioradialis and biceps µ and Modified Ashworth Scales, but no correlation with Fugl-Meyer Assessment. INTERPRETATION: Elastography can provide muscle-specific shear elastic modulus estimations of spastic brachioradialis and biceps brachialis, which are distinct from the nonspastic side. In some patients, there was no clear correspondence of the Fugl-Meyer Assessment functional scale with Modified Ashworth Scales and µ, suggesting that spasticity is not the only determinant of arm function. Additionally, shear wave elastography of brachioradialis and biceps brachialis muscles may guide the spasticity treatment, for instance, selecting the preferable candidate for botulinum toxin therapy.

Cortical and spinal excitability changes after repetitive transcranial magnetic stimulation combined to physiotherapy in stroke spastic patients.

OBJECTIVE: Repetitive Transcranial Magnetic Stimulation (rTMS) has been used to treat post-stroke upper limb spasticity (ULS) in addition to physiotherapy (PT). To determine whether rTMS associated with PT modulates cortical and spinal cord excitability as well as decreases ULS of post-stroke patients. METHODS: Twenty chronic patients were randomly assigned to either the intervention group-1 Hz rTMS on the unaffected hemisphere and PT, or control group-sham stimulation and PT, for ten sessions. Before and after sessions, ULS was measured using the modified Ashworth scale and cortical excitability using the output intensity of the magnetic stimulator (MSO). The spinal excitability was measured by the Hmax/Mmax ratio of the median nerve at baseline, at the end of treatment, and at the 4-week follow-up. RESULTS: The experimental group showed at the end of treatment an enhancement of cortical excitability, i.e., lower values of MSO, compared to control group (p = 0.044) and to baseline (p = 0.028). The experimental group showed a decreased spinal cord excitability at the 4-week follow-up compared to control group (p = 0.021). ULS decreased by the sixth session in the experimental group (p < 0.05). CONCLUSION: One-hertz rTMS associated with PT increased the unaffected hemisphere excitability, decreased spinal excitability, and reduced post-stroke ULS.

Transcranial direct current stimulation: before, during, or after motor training?

Noninvasive brain stimulation has recently been used to augment motor training-induced plasticity. However, the exact time during which noninvasive brain stimulation can be combined with motor therapy to maximize neuroplasticity and behavioral changes is unknown. We conducted a randomized sham-controlled crossover trial to examine when (before, during, or after training) transcranial direct current stimulation (tDCS) should be applied to best reinforce motor training-induced plasticity in 12 healthy right-handed participants (mean age: 21.8±1.6) who underwent active or sham tDCS combined with motor training. Transcranial magnetic stimulation-elicited motor-evoked potentials from the right first dorsal interosseous muscle were recorded before (baseline) and immediately after each session. The training task comprised four practice trials - 3 min each (30 s pause between trials) - of repetitive finger movements (thumb abduction/adduction) with the right hand. Anodal tDCS (1 mA, 13 min, on the motor primary cortex) was applied before, during, and after the training. Compared with baseline motor-evoked potentials and the sham condition, tDCS that was applied before, but not during or after, the motor task enhanced corticospinal excitability. These data suggest that tDCS performed before - not during or after - promotes optimization of motor training-induced plasticity.

Efficacy of coupling repetitive transcranial magnetic stimulation and physical therapy to reduce upper-limb spasticity in patients with stroke: a randomized controlled trial.

OBJECTIVE: To assess the efficacy of inhibitory repetitive transcranial magnetic stimulation (rTMS) for decreasing upper-limb muscle tone after chronic stroke. DESIGN: A randomized sham-controlled trial with a 4-week follow-up. SETTING: Research hospital. PARTICIPANTS: Patients with stroke (N=20) with poststroke upper limb spasticity. INTERVENTIONS: The experimental group received rTMS to the primary motor cortex of the unaffected side (1500 pulses; 1Hz; 90% of resting motor threshold for the first dorsal interosseous muscle) in 10 sessions, 3d/wk, and physical therapy (PT). The control group received sham stimulation and PT. MAIN OUTCOME MEASURES: Modified Ashworth scale (MAS), upper-extremity Fugl-Meyer assessment, FIM, range of motion, and stroke-specific quality-of-life scale. All outcomes were measured at baseline, after treatment (postintervention), and at a 4-week follow-up. A clinically important difference was defined as a reduction of ≥1 in the MAS score. RESULTS: Friedman test revealed that PT is efficient for significantly reducing the upper limb spasticity of patients only when it is associated with rTMS. In the experimental group, 90% of the patients at postintervention and 55.5% at follow-up showed a decrease of ≥1 in the MAS score, representing clinically important differences. In the control group, 30% of the patients at postintervention and 22.2% at follow-up experienced clinically meaningful changes. There were no differences between the groups at any time for any of the other outcome measures, indicating that both groups demonstrated similar behaviors over time for all variables. CONCLUSIONS: rTMS associated with PT can be beneficial in reducing poststroke spasticity. However, more studies are needed to clarify the clinical changes underlying the reduction in spasticity induced by noninvasive brain stimulations.