Anodal transcranial direct current stimulation for chronic pain in the elderly: a pilot study.

BACKGROUND AND AIMS: Transcranial direct current stimulation (tDCS) is a non-invasive neuromodulatory technique that can affect human pain perception. The present open-label, single-arm study investigated whether primary motor cortex anodal tDCS treatment reduces chronic foot pain intensity and improves depression and pain-related anxiety symptoms in patients with chronic plantar fasciitis. METHODS: Ten patients with symptomatic treatment-resistant plantar fasciitis were enrolled in the study. The treatment consisted of anodal tDCS over the motor area of the leg contralateral to the symptomatic foot for 20 min, at 2 mA for 5 consecutive days. Pre-tDCS (T0), post-tDCS (T1), 1 week (T2), and 4 weeks (T3) post-treatment assessments were conducted consisting of the Visual Analog Scale for pain intensity, the Foot Function Index (FFI), the Pain Anxiety Symptom Scale (PASS-20), and the Hamilton Rating Scale for Depression (HDRS-17 items). RESULTS: Anodal tDCS treatment induced a significant improvement in pain intensity; FFI and PASS scores that were maintained up to 4 weeks post-treatment. In addition, patients reported taking fewer pain medication tablets following the treatments. DISCUSSION AND CONCLUSIONS: Our results indicate that anodal tDCS may be a viable treatment to control pain and psychological comorbidity in elderly patients with treatment-resistant foot pain.

Neural circuits underlying motor facilitation during observation of implied motion.

In the present study we used single and paired-pulse Transcranial Magnetic Stimulation (TMS) to evaluate the effect of implied motion on primary motor cortex microcircuits. We found that observation of the implied motion of a static image increases MEP amplitude and reduces short-interval intracortical inhibition (SICI), without significant modulation of intracortical facilitation and sensory-motor integration. Our results add to the existing literature on the activation of the observation-execution matching system and describe a selective modulation of GABAergic cortical microcircuits during observation of implied motion.

Symmetric corticospinal excitability and representation of vastus lateralis muscle in right-handed healthy subjects.

The purpose of this study was to determine the size and location of the representations of the anterior thigh muscles on the human motor cortex in the dominant and non-dominant hemispheres. Motor-evoked potentials (MEPs) induced by transcranial magnetic stimulation were recorded from the right and left vastus lateralis (rVL, lVL) muscles. A total of ten right-handed healthy volunteers participated in the study. In a single session experiment, we investigated VL muscle corticospinal excitability (motor threshold, MEP size, short interval intracortical inhibition, intracortical facilitation) and cortical representation (map area, volume, and location) in the dominant and non-dominant hemispheres. The motor threshold, MEPs, and intracortical excitability did not differ significantly between the hemispheres (P > 0.05). Furthermore, no difference between sides was found in the location of VL motor representation (mediolateral and anteroposterior axis) or in map area and volume (P > 0.05). Vastus lateralis muscle corticospinal excitability and cortical map were symmetrical in right-handed subjects. Future studies on patients with unilateral lower extremity injuries could examine side-to-side plastic reorganization in corticomotor output and map location in both hemispheres.