Short Intracortical Inhibition During Voluntary Movement Reveals Persistent Impairment Post-stroke.

Short intracortical inhibition (SICI) is a GABA-mediated phenomenon, argued to mediate selective muscle activation during coordinated motor activity. Markedly reduced SICI has been observed in the acute period following stroke and, based on findings in animal models, it has been posited this disinhibitory phenomenon may facilitate neural plasticity and contribute to early motor recovery. However, it remains unresolved whether SICI normalizes over time, as part of the natural course of stroke recovery.

Does inhibitory repetitive transcranial magnetic stimulation augment functional task practice to improve arm recovery in chronic stroke?

Introduction. Restoration of upper extremity (UE) functional use remains a challenge for individuals following stroke. Repetitive transcranial magnetic stimulation (rTMS) is a noninvasive modality that modulates cortical excitability and is being explored as a means to potentially ameliorate these deficits.

Cognitive effects of treatment of depression with repetitive transcranial magnetic stimulation.

Background And Objective: We previously reported a randomized, sham-controlled trial of 5 Hz dorsolateral prefrontal left- and right-side repetitive transcranial magnetic stimulation (rTMS) in 48 participants with a medically refractory major depressive disorder. Depression improved most with right-side cranial stimulation, both rTMS and sham, and to a lesser degree with left rTMS. Because depression is often associated with cognitive impairment, in this study we sought to determine whether our earlier participants had treatment-induced changes in cognition, which cognitive domains (language, executive, visuospatial, verbal episodic memory, attention) were affected, and whether treatment-induced cognitive changes were related either to improvement in depression or to other treatment variables, such as right versus left treatment and rTMS versus sham.

Motor evoked potential depression following repetitive central motor initiation.

Prior reports have described a transient and focal decline in transcranial magnetic stimulation (TMS)-induced motor evoked potential (MEP) amplitude following fatiguing motor tasks. However, the neurophysiological causes of this change in MEP amplitude are unknown. The aim of this study was to determine whether post-task depression of MEPs is associated with repetitive central motor initiation.

Right and left dorsolateral pre-frontal rTMS treatment of refractory depression: a randomized, sham-controlled trial.

We conducted a prospective, randomized, sham-controlled, double blind, parallel group study of right or left pre-frontal rTMS in 48 subjects with medication-resistant depression. Two thousand (50x8-s trains of 5Hz) stimuli at MEP threshold were delivered each weekday for 2weeks. We employed a sham coil and simultaneous electrical stimulation of the scalp to simulate rTMS.

The clinical diagnostic utility of transcranial magnetic stimulation: report of an IFCN committee.

The review focuses on the clinical diagnostic utility of transcranial magnetic stimulation (TMS). The central motor conduction time (CMCT) is a sensitive method to detect myelopathy and abnormalities may be detected in the absence of radiological changes. CMCT may also detect upper motor neuron involvement in amyotrophic lateral sclerosis.

Use of transcranial magnetic stimulation to influence behavior.

Transcranial magnetic stimulation (TMS) is a noninvasive technique that allows researchers to induce electrical currents in focal areas of the cerebral cortex. These currents can transiently activate or inhibit focal cortical areas and thus influence behavior. In the 20 years since its introduction, TMS has been applied to the study and treatment of a wide variety of neurologic and psychiatric conditions.

Repetitive transcranial magnetic stimulation as an adjunct to constraint-induced therapy: an exploratory randomized controlled trial.

Objective: To test the potential adjuvant effect of repetitive transcranial magnetic stimulation (rTMS) on motor learning in a group of stroke survivors undergoing constraint-induced therapy (CIT) for upper-limb hemiparesis.

Design: This was a prospective randomized, double-blind, sham-controlled, parallel group study. Nineteen individuals, one or more years poststroke, were randomized to either a rTMS + CIT (n = 9) or a sham rTMS + CIT (n = 10) group and participated in the 2-wk intervention.

Ipsilateral motor activation during unimanual and bimanual motor tasks.

Objective: To test for the presence and possible asymmetry of ipsilateral motor activation during unimanual and bimanual motor tasks.

Methods: Twelve right-handed healthy subjects underwent motor evoked potential (MEP) measurement of one hand (target-hand) while the other hand (task-hand) performed different motor tasks. The target-hand was either at rest (first experiment) or performed a Perdue PegBoard task (second experiment).

Diagnosis and Treatment of Chronic Immune-mediated Neuropathies.

The chronic autoimmune neuropathies are a diverse group of disorders, whose diagnosis and classification is based on the clinical presentations and results of ancillary tests. In chronic inflammatory demyelinating polyneuropathy, controlled therapeutic trials demonstrated efficacy for intravenous gamma-globulins, corticosteroids, and plasmaphereis. In multifocal motor neuropathy, intravenous gamma-globulins have been shown to be effective.

Lateralized asymmetry of facial motor evoked potentials.

Background: There is considerable evidence that emotions are expressed more intensely on the left side of the face. This asymmetry could reflect a right hemisphere advantage in processing emotional material or an asymmetry in corticobulbar motor systems. Transcranial magnetic stimulation (TMS) was used to test for lateralized asymmetry in the cortical control of muscles of facial expression in the lower face.

Effect of repetitive transcranial magnetic stimulation on rate of memory acquisition.

Repetitive transcranial magnetic stimulation (rTMS) may temporarily accelerate knowledge acquisition by neural networks, possibly by promoting rapid Hebbian learning. The authors tested this hypothesis in 20 normal subjects by comparing the impact of 25 minutes of high-frequency left dorsolateral prefrontal rTMS with that of sham rTMS on subsequent knowledge acquisition in several procedural and declarative memory domains. No significant group effects, positive or negative, were noted for any memory acquisition test, but prefrontal rTMS did reduce motor evoked potential threshold.

Mental object rotation in Parkinson's disease.

Deficits in visual-spatial ability can be associated with Parkinson's disease (PD), and there are several possible reasons for these deficits. Dysfunction in frontal-striatal and/or frontal-parietal systems, associated with dopamine deficiency, might disrupt cognitive processes either supporting (e.g.

Corticosteroid treatment of mitochondrial encephalomyopathies.

Background: Mitochondrial encephalopathy with lactic acidosis and stroke-like symptoms (MELAS) is a multisystem disorder characterized by stroke-like episodes, seizures, dementia, headaches,evidence of mitochondrial myopathy. Lactic acidosis and ragged red fibers are often present. A variety of therapies have been used with inconclusive and disappointing results.

Cerebral blood flow changes in depressed patients after treatment with repetitive transcranial magnetic stimulation: evidence of individual variability.

Objective: To elucidate the neural mechanisms of depression.

Background: Despite extensive study, the neurophysiology of the brain's state(s) corresponding to depression remains uncertain.

Methods: HMPAO single photon emission computed tomographic (SPECT) scans were obtained from eight adults diagnosed with major depression resistant to medication (average age 51 years; 4 men) before and immediately after 10 days of 20 Hz repetitive transcranial magnetic stimulation (rTMS) (2000 stimuli/daily 30' treatment).

Immobilization dystonia.

The mechanisms underlying dystonia after injury are unclear. Pain has been implicated as an important factor. We report four patients who exhibited segmental dystonia following removal of a cast, only two of whom experienced pain during casting.