Cortical Plasticity Induction by Pairing Subthalamic Nucleus Deep-Brain Stimulation and Primary Motor Cortical Transcranial Magnetic Stimulation in Parkinson's Disease.

Unlabelled: Noninvasive brain stimulation studies have shown abnormal motor cortical plasticity in Parkinson's disease (PD). These studies used peripheral nerve stimulation paired with transcranial magnetic stimulation (TMS) to primary motor cortex (M1) at specific intervals to induce plasticity. Induction of cortical plasticity through stimulation of the basal ganglia (BG)-M1 connections has not been studied.

Effects of subthalamic nucleus stimulation on motor cortex plasticity in Parkinson disease.

Objective: We hypothesized that subthalamic nucleus (STN) deep brain stimulation (DBS) will improve long-term potentiation (LTP)-like plasticity in motor cortex in Parkinson disease (PD).

Methods: We studied 8 patients with PD treated with STN-DBS and 9 age-matched healthy controls. Patients with PD were studied in 4 sessions in medication (Med) OFF/stimulator (Stim) OFF, Med-OFF/Stim-ON, Med-ON/Stim-OFF, and Med-ON/Stim-ON states in random order.

Pedunculopontine nucleus evoked potentials from subthalamic nucleus stimulation in Parkinson's disease.

The effects of subthalamic nucleus (STN) stimulation on the pedunculopontine nucleus area (PPNR) evoked activities were examined in two patients with Parkinson's disease. The patients had previously undergone bilateral STN deep brain stimulation (DBS) and subsequently received unilateral DBS electrodes in the PPNR. Evoked potentials were recorded from the local field potentials (LFP) from the PPNR with STN stimulation at different frequencies and bipolar contacts.

Increased motor cortical facilitation and decreased inhibition in Parkinson disease.

Objective: To identify the changes in motor cortical facilitatory and inhibitory circuits in Parkinson disease (PD) by detailed studies of their time courses and interactions.

Methods: Short-interval intracortical facilitation (SICF) and short-interval intracortical inhibition (SICI) were measured with a paired-pulse paradigm using transcranial magnetic stimulation. Twelve patients with PD in both ON and OFF medication states and 12 age-matched healthy controls were tested.

Differential response of speed, amplitude, and rhythm to dopaminergic medications in Parkinson's disease.

Although movement impairment in Parkinson's disease includes slowness (bradykinesia), decreased amplitude (hypokinesia), and dysrhythmia, clinicians are instructed to rate them in a combined 0-4 severity scale using the Unified Parkinson's Disease Rating Scale motor subscale. The objective was to evaluate whether bradykinesia, hypokinesia, and dysrhythmia are associated with differential motor impairment and response to dopaminergic medications in patients with Parkinson's disease. Eighty five Parkinson's disease patients performed finger-tapping (item 23), hand-grasping (item 24), and pronation-supination (item 25) tasks OFF and ON medication while wearing motion sensors on the most affected hand.

Effects of theta burst stimulation on motor cortex excitability in Parkinson's disease.

Objective: Long-term potentiation (LTP)-like plasticity induced by paired associative stimulation (PAS) is impaired in Parkinson's disease (PD). Intermittent theta burst stimulation (iTBS) is another rTMS protocol that produces LTP-like effects and increases cortical excitability but its effects are independent of afferent input. The aim of the present study was to examine the effects of iTBS on cortical excitability in PD.

Movement related potentials and oscillatory activities in the human internal globus pallidus during voluntary movements.

Objective: To study internal globus pallidus (GPi) activities and the interactions among the bilateral GPi and motor cortical areas during voluntary movements.

Methods: Five patients with cervical dystonia who underwent bilateral GPi deep brain stimulation (DBS) were studied. Local field potentials from the GPi DBS electrodes and EEG were recorded while the patients performed externally triggered and self-initiated right wrist movements.

Direct demonstration of inhibitory interactions between long interval intracortical inhibition and short interval intracortical inhibition.

A subthreshold conditioning stimulation (CS) suppresses the motor-evoked potential (MEP) generated by a test stimulation (TS) at interstimulus intervals (ISIs) of 1–5ms in a paired-pulse transcranial magnetic stimulation (TMS) protocol, a phenomenon termed short interval intracortical inhibition (SICI). Intracortical facilitation (ICF) occurs at ISIs of 7–30ms. Long interval intracortical inhibition (LICI) is elicited with suprathreshold CS preceding the TS at ISIs of 50–200 ms.

The modified bradykinesia rating scale for Parkinson's disease: reliability and comparison with kinematic measures.

Bradykinesia encompasses slowness, decreased movement amplitude, and dysrhythmia. Unified Parkinson's Disease Rating Scale-based bradykinesia-related items require that clinicians condense abnormalities in speed, amplitude, fatiguing, hesitations, and arrests into a single score. The objective of this study was to evaluate the reliability of a modified bradykinesia rating scale, which separately assesses speed, amplitude, and rhythm and its correlation with kinematic measures from motion sensors.

The dominant-STN phenomenon in bilateral STN DBS for Parkinson's disease.

In some patients with Parkinson's disease (PD) and bilateral STN-DBS the motor benefit from one STN alone appears similar to the improvement obtained with bilateral STN-DBS. Thus, we hypothesized that some patients have a "dominant-STN," whose stimulation achieves similar results than bilateral stimulation. Twenty-two consecutive PD patients with bilateral STN-DBS were assessed in 4 randomized conditions: bilateral off-stimulation, bilateral on-stimulation, unilateral right- and unilateral left-stimulation.

Somatosensory evoked potentials recorded from the human pedunculopontine nucleus region.

The pedunculopontine nucleus region (PPNR) is an integral component of the midbrain locomotor region and has widespread connections with the cortex, thalamus, brain stem, cerebellum, spinal cord, and especially, the basal ganglia. No previous study examined the somatosensory connection of the PPNR in human. We recorded somatosensory evoked potentials (SEP) from median nerve stimulation through deep brain stimulation (DBS) electrodes implanted in the PPNR in 8 patients (6 with Parkinson's disease, 2 with progressive supranuclear palsy).

Gamma knife thalamotomy for disabling tremor: a blinded evaluation.

Background: Gamma knife thalamotomy (GKT) has been used as a therapeutic option for patients with disabling tremor refractory to medications. Impressive improvement of tremor has been reported in the neurosurgical literature, but the reliability of such data has been questioned.

Objective: To prospectively evaluate clinical outcomes after GKT for disabling tremor with blinded assessments.

The nature and time course of cortical activation following subthalamic stimulation in Parkinson's disease.

We studied the time course and nature of interactions between the subthalamic nucleus (STN) and the motor cortex in 8 Parkinson disease (PD) patients with chronically implanted STN deep-brain stimulation (DBS) electrodes. We first identified the cortical evoked potentials following STN stimulation. The most consistent potential was positive wave with peak latency of 22.

Involvement of the basal ganglia and cerebellar motor pathways in the preparation of self-initiated and externally triggered movements in humans.

The subthalamic nucleus (STN) is part of the cortico-basal ganglia (BG)-thalamocortical circuit, whereas the ventral lateral nucleus of the thalamus (VL) is a relay nucleus in the cerebello-dentato-thalamocortical (CTC) pathway. Both pathways have been implicated in movement preparation. We compared the involvement of the STN and VL in movement preparation in humans by recording local field potentials (LFPs) from seven patients with Parkinson's disease with deep-brain stimulation (DBS) electrodes in the STN and five patients with tremor and electrodes in VL.