Long-term levodopa administration in chronic stroke patients. A clinical and neurophysiologic single-blind placebo-controlled cross-over pilot study.

PURPOSE: Promising new rehabilitative approaches to improve the substantial motor disability associated with chronic stroke include pharmacotherapy to enhance motor recovery. We conducted a single-blind placebo-controlled crossover pilot study to investigate the effects of prolonged treatment with L-DOPA in stroke patients. METHODS: Ten chronic (10-48 months) stroke patients received placebo or L-DOPA 100 mg daily for 5 weeks. During drug's treatment patients suspended physiotherapy. Patients underwent clinical evaluation (Rivermead Motor Assessment, Nine Hole Peg Test, and 10 meter walking test) and transcranial magnetic stimulation recordings from the affected and unaffected hemisphere (resting motor threshold, motor evoked potential amplitude and cortical silent period) before and after 5 weeks of treatment. RESULTS: After L-DOPA treatment patients improved their walking speed (p < 0.01) and manual dexterity ( p < 0.01) with the affected hand, the cortical silent period over the affected hemisphere lengthened (p < 0.01), while no changes were found in placebo-group. CONCLUSION: A 5-week course of oral L-DOPA in a single daily dose substantially improves motor performance in patients with chronic stroke and could do so by modulating motor cortical excitability (cortical silent period lengthening) suggesting that cortical inhibitory mechanisms have a role in motor recovery after stroke. Pharmacotherapy could be a useful therapeutic approach for chronic stroke patients.

Motor cortical disinhibition during early and late recovery after stroke.

BACKGROUND: Functional neuroimaging studies show adaptive changes in areas adjacent and distant from the stroke. This longitudinal study assessed whether changes in cortical excitability in affected and unaffected motor areas after acute stroke correlates with functional and motor recovery. METHODS: We studied 13 patients with moderate to severe hemiparesis 5 to 7 days (T1), 30 days (T2), and 90 days (T3) after acute unilateral stroke, as well as 10 healthy controls. We used paired-pulse transcranial magnetic stimulation to study intracortical inhibition and facilitation, recording from the bilateral thenar eminences. F waves were also recorded. RESULTS: At T1, all patients showed significantly reduced intracortical inhibition in the unaffected hemisphere. At T2, in patients whose motor function recovered, intracortical inhibition in the unaffected hemisphere returned to normal. In patients with poor clinical motor recovery, abnormal disinhibition persisted in both hemispheres. At T3, in patients whose motor function progressively recovered, the abnormal disinhibition in the unaffected hemisphere decreased further, whereas in patients whose motor function remained poor, abnormal inhibition in the unaffected hemisphere persisted. No modification of F-wave latency and amplitude were found in patients and controls. CONCLUSIONS: During early days after stroke, motor cortical disinhibition involves both cerebral hemispheres. Longitudinal changes in motor disinhibition of the unaffected hemisphere may reflect the degree of clinical motor recovery.

Role, indications and controversies of levodopa administration in chronic stroke patients.

Stroke leaves many patients disabled even after rehabilitative training, representing a major cause of disability. Several approaches to improve outcomes have been attempted in recent years, with only relative benefit. Emerging evidences show a potential role of pharmacological intervention to enhance motor recovery after stroke. Contrasting evidence are coming from experimental and clinical studies, so far, and pharmacological intervention during rehabilitation represents a major controversial in neurorehabilitation. Dopaminergic stimulation appears as one of the most promising way to improve motor recovery. Subject of this paper will be the ratio underlying the clinical use of levodopa in chronic stroke patients, trying to outline the most convincing evidences about a potential role of this drug in rehabilitative strategies.

Effect of median-nerve electrical stimulation on BOLD activity in acute ischemic stroke patients.

OBJECTIVE: To investigate blood oxygenation level-dependent (BOLD) activation during somatosensory electrical stimulation of the median nerve in acute stroke patients and to determine its correlation with ischemic damage and clinical recovery over time. METHODS: Fourteen acute stroke patients underwent functional magnetic resonance imaging (fMRI) during contralesional median-nerve electrical stimulation 12-48 h after stroke. Findings were then validated by diffusion tensor imaging (DTI) and motor evoked potential by transcranial magnetic stimulation (TMS). RESULTS: Poor clinical recovery at three months was noted in four patients with no activation in the early days after stroke, whereas good clinical recovery was observed in eight patients with a normal activation pattern in the primary sensory motor area in the acute phase. In two patients BOLD activation correlated weakly with clinical recovery. Findings from TMS and DTI partially correlated with clinical recovery and functional scores. CONCLUSIONS: Clinically relevant insights into the "functional reserve" of stroke patients gained with peripheral nerve stimulation during fMRI may carry prognostic value already in the acute period of a cerebrovascular accident. SIGNIFICANCE: BOLD activation maps could provide insights into the functional organization of the residual systems and could contribute to medical decision making in neurological and rehabilitative treatment.

Effect of a Static Magnetic Field (1.5T) on Brain Oscillatory Activities in Resting State Condition.

The aim of the present study was to compare the EEG signal recorded outside and inside a 1.5T magnetic resonance (MR) scanner. The EEG was recorded in eyes open and eyes closed conditions using a digital recording MR-compatible system. To characterize how a static magnetic field induces changes in EEG signal, EEG data were analyzed using FFT frequency analysis. No significant difference between the alpha powers recorded outside and inside the magnetic field was observed in eyes closed conditions. However, in eyes open condition there was a significant increase in alpha power inside the magnet in comparison to the outside position. The changes in alpha power according to the eyes open/closed conditions could be inversely correlated to a subject's state of wakefulness and due to some physiological changes, rather than an effect of the magnetic field. This experiment suggests that subjects' state of wakefulness is of prime concern when performing functional MRI.

Anti-GD2-like IgM autoreactivity in multiple sclerosis patients.

Seric IgM autoreactivity in 100 multiple sclerosis (MS) and 106 control (70 of whom had other neurological diseases) patients was assessed either by immunohistochemistry on normal human CNS tissue or to GD2, GD1a, GD3 by ELISA and thin layer chromatography (TLC) techniques. By double immunohistochemistry, we found that 44% of the total MS population showed seric IgM reactivity to oligodendrocytes and myelin, this finding being particularly frequent in patients with secondary progressive MS. In the non-MS cohort, positive signals were seen only in one patient. In all cases, extraction of lipids from CNS sections abolished the immunoreactivity. Among the gangliosides investigated by ELISA, anti-GD2-like IgM autoantibodies were detected in the serum of 30% of MS patients, a subgroup of whom (below 10%) reacted also with GD1a and/or GD3. More than 85% of MS cases with anti-GD2-like IgM immunoreactivity by ELISA showed also IgM antioligodendrocyte/myelin staining by immunohistochemistry. However, no immunostaining in MS sera was observed when gangliosides were resolved by TLC. A positive correlation with neurological disability was observed, as the Expanded Disability Status Scale of MS patients with anti-GD2-like IgM autoreactivity by ELISA was significantly worse than seronegative MS cases. The results of the present study enforce the role of glycolipids as potential autoantigens and of IgM autoantibodies in MS pathogenesis.