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Freezing of gait is a common, debilitating feature of Parkinson's disease. We have studied gait planning in patients with freezing of gait, using motor imagery of walking in combination with functional magnetic resonance imaging. This approach exploits the large neural overlap that exists between planning and imagining a movement. In addition, it avoids(More)
OBJECTIVE To assess the variability of transcranial magnetic stimulation paired pulse measurements of cortical excitability between subjects, between sessions and within subjects within sessions. METHODS In experiment 1, intracortical inhibition and facilitation were assessed with a fixed conditioning stimulus intensity (CSI) of 80% of active motor(More)
The pathophysiology underlying freezing of gait (FOG) in Parkinson's disease remains incompletely understood. Patients with FOG ("freezers") have a higher temporal variability and asymmetry of strides compared to patients without FOG ("non-freezers"). We aimed to extend this view, by assessing spatial variability and asymmetry of steps and interlimb(More)
The clinical assessment of freezing of gait (FOG) provides great challenges. Patients often do not realize what FOG really is. Assessing FOG is further complicated by the episodic, unpredictable, and variable presentation, as well as the complex relationship with medication. Here, we provide some practical recommendations for a standardized clinical(More)
OBJECTIVE We examined how corticospinal excitability was affected by motor imagery of foot dorsiflexion and motor imagery of gait. METHODS Transcranial magnetic stimulation was applied over the primary motor cortex of 16 young healthy subjects while they performed imaginary foot dorsiflexions (Experiment I) and imaginary walking (Experiment II).(More)
Gait disorders are common and often devastating companions of ageing, leading to reductions in quality of life and increased mortality. Here, we present a clinically oriented approach to neurological gait disorders in the elderly population. We also draw attention to several exciting scientific developments in this specialty. Our first focus is on the(More)
OBJECTIVE A previous study showed no effect of 1Hz repetitive transcranial magnetic stimulation (rTMS) on tics in Gilles de la Tourette Syndrome (GTS). We modified the rTMS protocol in order to investigate some of the possible methodological reasons for the negative outcome in that study. METHODS In a single blinded placebo-controlled cross-over study in(More)
Freezing of gait (FOG) is a disabling feature of Parkinson's disease. Emerging evidence suggests that dysfunction of the pedunculopontine nucleus (PPN) and pontomedullary reticular formation (pmRF) plays a role in the causation of FOG. These brainstem structures can be examined by the StartReact paradigm, which utilizes a startling stimulus to accelerate(More)
Freezing of gait is a common and disabling symptom in patients with parkinsonism, characterised by sudden and brief episodes of inability to produce effective forward stepping. These episodes typically occur during gait initiation or turning. Treatment is important because freezing of gait is a major risk factor for falls in parkinsonism, and a source of(More)
OBJECTIVE To describe the phenotype of levodopa-induced "on" freezing of gait (FOG) in Parkinson disease (PD). METHODS We present a diagnostic approach to separate "on" FOG (deterioration during the "on state") from other FOG forms. Four patients with PD with suspected "on" FOG were examined in the "off state" (>12 hours after last medication intake), "on(More)