Dopamine-responsive and dopamine-resistant resting tremor in Parkinson disease.

Objective: We tested the hypothesis that there are 2 distinct phenotypes of Parkinson tremor, based on interindividual differences in the response of resting tremor to dopaminergic medication. We also investigated whether this pattern is specific to tremor by comparing interindividual differences in the dopamine response of tremor to that of bradykinesia.

Methods: In this exploratory study, we performed a levodopa challenge in 76 tremulous patients with Parkinson tremor.

Coherence of jaw and neck muscle activity during sleep bruxism.

Background: Studies have shown co-contraction of jaw and neck muscles in healthy subjects during (sub) maximum voluntary jaw clenching, indicating functional inter-relation between these muscles during awake bruxism. So far, coherence of jaw and neck muscles has not been evaluated during either awake or sleep bruxism.

Objective: The objective of this study was to evaluate the coherence between jaw and neck muscle activity during sleep bruxism.

Billiards-related dystonia: A new task-specific dystonia.

We report the first videotaped case of focal and task-specific dystonia of the upper limb that occurred exclusively while using a cue during billiard playing. The repetitive movements in conjunction with a highly skilled performance likely contributed to the development of this focal dystonia.

On the electrode positioning for bipolar EMG recording of forearm extensor and flexor muscle activity after transcranial magnetic stimulation.

After stroke, motor pathways are often affected, leading to paresis. It remains difficult to reliably predict motor recovery of the upper extremity, for which transcranial magnetic stimulation (TMS) may add to clinical examination. Placement of the surface electromyography (sEMG) electrodes in TMS is essential for information about specific muscle groups and corticospinal pathways.

Cognitive Stress Reduces the Effect of Levodopa on Parkinson's Resting Tremor.

Aims: Resting tremor in Parkinson's disease (PD) increases markedly during cognitive stress. Dopamine depletion in the basal ganglia is involved in the pathophysiology of resting tremor, but it is unclear whether this contribution is altered under cognitive stress. We test the hypothesis that cognitive stress modulates the levodopa effect on resting tremor.

The patient's perspective: The effect of levodopa on Parkinson symptoms.

Background: Dopaminergic medication adjustments in Parkinson's disease are often solely based on patient reports. However, it is unclear how well patient-based ratings of the levodopa response correlate with clinician-based ratings, and whether this correlation differs between motor symptoms. Here we compare patient-clinician agreement for the effect of levodopa on resting tremor and bradykinesia/rigidity.

Dynamic cortical gray matter volume changes after botulinum toxin in cervical dystonia.

Previous electrophysiological and functional imaging studies in focal dystonia have reported on cerebral reorganization after botulinum toxin (BoNT) injections. With the exception of microstructural changes, alterations in gray matter volume after BoNT have not been explored. In this study, we sought to determine whether BoNT influences gray matter volume in a group of cervical dystonia (CD) patients.

Small biparietal diameter and head circumference are part of the phenotype instead of independent prognostic markers in fetuses with spinal dysraphism.

Objective: The aim of this retrospective study was to assess the fetal biparietal diameter (BPD) and head circumference (HC) in the second trimester of pregnancy in fetuses with open spinal dysraphism.

Methods: BPD and HC were measured at 16-26 weeks in 74 fetuses with open spinal dysraphism and compared with reference values.

Results: BPD was smaller in fetuses with open spinal dysraphism.

Definition dependent properties of the cortical silent period in upper-extremity muscles, a methodological study.

Background: To explore if stimulus-response (S-R) characteristics of the silent period (SP) after transcranial magnetic stimulation (TMS) are affected by changing the SP definition and by changing data presentation in healthy individuals. This information would be clinically relevant to predict motor recovery in patients with stroke using stimulus-response curves.

Methods: Different landmarks to define the SP onset and offset were used to construct S-R curves from the biceps brachii (BB) and abductor digiti minimi (ADM) muscles in 15 healthy participants using rectified versus non-rectified surface electromyography (EMG).

Altered striatal and pallidal connectivity in cervical dystonia.

Cervical dystonia is a neurological movement disorder characterized by involuntary, abnormal movements of the head and neck. Injecting the overactive muscles with botulinum toxin is the gold standard treatment, supported by good evidence (Delnooz and van de Warrenburg in Ther Adv Neurol Disord 5:221-240, 2012). Current views on its pathophysiology support a role for the basal ganglia, although there are probably more widespread abnormalities in brain networks in which the basal ganglia are important nodes.

Task-free functional MRI in cervical dystonia reveals multi-network changes that partially normalize with botulinum toxin.

Cervical dystonia is characterized by involuntary, abnormal movements and postures of the head and neck. Current views on its pathophysiology, such as faulty sensorimotor integration and impaired motor planning, are largely based on studies of focal hand dystonia. Using resting state fMRI, we explored whether cervical dystonia patients have altered functional brain connectivity compared to healthy controls, by investigating 10 resting state networks.

Motor evoked potentials and compound muscle action potentials as prognostic tools for neonates with spina bifida.

Unlabelled: MEPs and CMAPs as prognostic tools for spina bifida.

Aim: The aim of this prospective study was to determine the prognostic value of neurophysiological investigations compared to clinical neurological examination in infants with spina bifida.

Methods: Thirty-six neonates born with spina bifida between 2002 and 2007 were evaluated and followed for 2 years.

Topography of maturational changes in EEG burst spectral power of the preterm infant with a normal follow-up at 2 years of age.

Objective: To quantify the electroencephalography (EEG) burst frequency spectrum of preterm infants by automated analysis and to describe the topography of maturational change in spectral parameters.

Methods: Eighteen preterm infants <32weeks gestation and normal neurological follow-up at 2years underwent weekly 4-h EEG recordings (10-20 system). The recordings (n=77) represent a large variability in postmenstrual age (PMA, 28-36weeks).

Automatic burst detection for the EEG of the preterm infant.

To aid with prognosis and stratification of clinical treatment for preterm infants, a method for automated detection of bursts, interburst-intervals (IBIs) and continuous patterns in the electroencephalogram (EEG) is developed. Results are evaluated for preterm infants with normal neurological follow-up at 2 years. The detection algorithm (MATLAB®) for burst, IBI and continuous pattern is based on selection by amplitude, time span, number of channels and numbers of active electrodes.

Maturational changes in automated EEG spectral power analysis in preterm infants.

Our study aimed at automated power spectral analysis of the EEG in preterm infants to identify changes of spectral measures with maturation. Weekly (10-20 montage) 4-h EEG recordings were performed in 18 preterm infants with GA <32 wk and normal neurological follow-up at 2 y, resulting in 79 recordings studied from 27(+4) to 36(+3) wk of postmenstrual age (PMA, GA + postnatal age). Automated spectral analysis was performed on 4-h EEG recordings.

Dynamic cerebral autoregulation in the old using a repeated sit-stand maneuver.

The aim of this study was to assess the feasibility and reproducibility of a simple and nonobtrusive repeated sit-stand maneuver to assess cerebral autoregulation (CA) in healthy old subjects >70 years. In 27 subjects aged 76 (SD 4) years, we continuously measured blood pressure using photoplethysmography and cerebral blood flow velocity in the middle cerebral artery (transcranial Doppler ultrasonography) during 5 min of sitting rest and again during repeated sit-stand maneuvers at 10 s (0.05 Hz) and 5 s (0.

Predicting hand motor recovery in severe stroke: the role of motor evoked potentials in relation to early clinical assessment.

Objective: The primary aim of this study was to compare the predictive value of motor evoked potentials (MEPs) and early clinical assessment with regard to long-term hand motor recovery in patients with profound hemiplegia after stroke.

Methods: The sample was an inception cohort of 39 stroke patients with an acute, ischemic, supratentorial stroke and an initial upper-extremity paralysis admitted to an academic hospital. Hand motor function recovery was defined at 26 weeks poststroke as a Fugl-Meyer Motor Assessment (FMA) hand score>3 points.

Compound muscle action potentials in newborn infants with spina bifida.

The aim of this study was to investigate the relationship between compound muscle action potentials (CMAPs) and neurological impairment in newborn infants with spina bifida. Thirty-one newborn infants (17 males, 14 females, mean gestational age 39 wks [SD 2]; mean birthweight 3336 g [SD 496]) with spina bifida were investigated at a median age of 2 days (range 1-18 d). Motor and sensory impairment and muscle stretch reflexes were assessed and neuroimaging was performed.

Stimulus-response characteristics of motor evoked potentials and silent periods in proximal and distal upper-extremity muscles.

Objective: To compare stimulus-response characteristics of both motor evoked potentials (MEP) and silent periods (SP) induced by transcranial magnetic stimulation (TMS) in proximal and distal upper-extremity muscles.

Methods: Stimulus-response curves of MEPs and SPs were obtained from the biceps brachii (BB) and abductor digiti minimi (ADM) muscles in 15 healthy participants. A nonlinear mixed model was used to fit the stimulus-response curves to a sigmoid Boltzmann function.

Supratentorial ischemic stroke: more than an upper motor neuron disorder.

The primary goal of this study was to identify secondary functional changes in the peripheral motor units of the paretic upper extremity (UE) in patients with severe ischemic stroke and to determine how these changes develop during the first weeks after stroke. An inception cohort of 27 consecutive patients with an acute ischemic supratentorial stroke and an initial UE paralysis was compared with 10 healthy control subjects. The ulnar nerve was electrically stimulated proximal to the wrist and electromyographic recordings were obtained from the abductor digiti minimi muscle.

The spectrum of polyneuropathies in childhood detected with electromyography.

Only a few studies have been reported describing polyneuropathies in a series of children. To study the clinical and neurophysiological spectrum of polyneuropathies in a large series of children and obtain an overview of their etiologies, this retrospective study reevaluated all electromyograms and electrophysiologic studies performed between 1995 and 2004 in children under 17 years of age at the Radboud University Nijmegen Medical Center, a tertiary neuromuscular reference center. Electromyograms revealing polyneuropathy were selected for further analysis (n = 118), and the medical records were reviewed to supplement electromyographic findings with the clinical diagnosis.

Are neuroradiological or neurophysiological characteristics associated with upper-extremity hypertonia in severe ischaemia in supratentorial stroke?

Objective: The primary goal was to identify the neuroradiological and neurophysiological risk factors for upper-extremity hypertonia in patients with severe ischaemic supratentorial stroke.

Design: Inception cohort.

Patients: Forty-three consecutive patients with an acute ischaemic supratentorial stroke and an initial upper-extremity paralysis admitted to an academic hospital recruited over a 1.

Are clinical characteristics associated with upper-extremity hypertonia in severe ischaemic supratentorial stroke?

Objective: The primary goal of this study was to identify clinical risk factors, in addition to muscle weakness, for upper-extremity hypertonia in patients with severe ischaemic supratentorial stroke. The secondary goal was to investigate the time course of upper-extremity hypertonia in these patients during the first 26 weeks post-stroke.

Design: Inception cohort.

Online maintenance of sensory and motor representations: effects on corticospinal excitability.

Flexible behavior requires the ability to delay a response until it is appropriate. This can be achieved by holding either a sensory or a motor representation online. Here we assess whether maintenance of sensory or motor material drives the motor system to different functional states, as indexed by alterations of corticospinal excitability.

Responses to lumbar magnetic stimulation in newborns with spina bifida.

Searching for a tool to quantify motor impairment in spina bifida, transcranial and lumbar magnetic stimulation were applied in affected newborn infants. Lumbar magnetic stimulation resulted in motor evoked potentials in both the quadriceps muscle and the tibialis anterior muscle in most (11/13) subjects. However, transcranial magnetic stimulation did not lead to any response at all.