Ipsilateral Frontal Areas Research Articles

Quantitative EEG Evaluation During Robot-Assisted Foot Movement.

Passiveand imagined limbmovements induce changes in cerebral oscillatory activity. Central modulatory effects play a role in plastic changes, and are of uttermost importance in rehabilitation. This has extensively been studied for upper limb, but less is known for lower limb. The aim of this study is to investigate the topographical distribution of event-related desynchronization/synchronization(ERD/ERS) and task-relatedcoherence during a robot-assisted and a motor imagery task of lower limb in healthy subjects to inform rehabilitation paradigms. 32-channels electroencephalogram (EEG) was recorded in twenty-one healthy right footed and handed subjects during a robot-assisted single-joint cyclic right ankle movement performed by the BTS ANYMOV robotic hospital bed. Data were acquired with a block protocol for passive and imagined movement at a frequency of 0.2 Hz. ERD/ERS and task related coherence were calculated in alpha1 (8-10 Hz), alpha2 (10.5-12.5 Hz) and beta (13-30 Hz) frequency ranges. During passive movement, alpha2 rhythm desynchronized overC3 and ipsilateral frontal areas (F4, FC2, FC6); betaERD was detected over the bilateral motor areas (Cz, C3, C4). During motor imagery, a significant desynchronization was evident for alpha1 over contralateral sensorimotor cortex (C3), for alpha2 over bilateral motor areas (C3 and C4), and for beta over central scalp areas. Task-related coherence decreased during passive movement in alpha2 band between contralateral central area (C3, CP5, CP1, P3) and ipsilateral frontal area (F8, FC6, T8); beta band coherence decreased between C3-C4 electrodes, and increased between C3-Cz. These data contribute to the understanding of oscillatory activity and functional neuronal interactions during lower limb robot-assisted motor performance. The final output of this line of research is to inform the design and development of neurorehabilitation protocols.

Role of associated cortical lesions in motor partial seizures and lenticulostriate infarcts.

In a population-based study, we evaluated seizures occurring in the first 15 days after strokes among 1,640 consecutive patients who had ischemic (814 infarcts with atheroma and 126 with cardiogenic embolism, 273 lacunar infarcts, 259 transient ischemic attacks) or hemorrhagic stroke (129 supratentorial hematomas and 24 subarachnoïd hemorrhage) on computed tomography (CT) scan. Ninety patients had an epileptic seizure in the first 15 days after stroke onset. Thirteen of the 90 had a lenticulostriate infarct, diagnosed on CT scan, without an apparent ipsilateral cortical ischemic lesion. No lenticulostriate hematoma was observed with seizures. To determine the possible existence of an ipsilateral cortical lesion, magnetic resonance imaging (MRI) with gadolinium perfusion, and HMPAO single photon emission CT (SPECT) were performed in the 13 patients with seizures. MRI showed an associated ipsilateral posterofrontal or anterotemporal cortical ischemic lesion in 11 cases, and SPECT showed decreased blood flow in the ipsilateral frontal area in all cases (superficial sylvian territory). Overall, 56 patients had a lenticulostriate infarct and clinical, CT, and MRI data from the 13 with seizures was compared with those of the 43 without seizures. Two criteria differentiated the two groups: the size of the lenticulostriate infarct was larger (8.3 vs. 3.9 cm3) and ipsilateral cortical ischemic lesions were more frequent in the group with seizures (84 vs. 9%).