Radiographic abnormalities and their clinical significance in patients with Parkinson disease who receive deep brain stimulation implants.

Objective: Preoperative MR images obtained in patients with Parkinson disease (PD) undergoing deep brain stimulation (DBS) often reveal incidental radiographic abnormalities (RAs). These findings range from small changes to gross pathologies. The effect of these findings on patients' clinical outcomes is unknown.

Demographics of focused ultrasound thalamotomy for essential tremor and trends in deep brain stimulation surgery after its introduction in the USA.

Background: Essential tremor (ET) is a movement disorder that affects 4%-5% of adults >65 years. For patients with medically refractory ET, neurosurgical interventions such as deep brain stimulation (DBS) and unilateral MR-guided focused ultrasound thalamotomy (MRgFUS) are available. In this retrospective cohort study, we examined the demographics of patients with ET who have received MRgFUS and evaluated trends in DBS usage in the USA after the introduction of MRgFUS in 2016.

Effect of levodopa on postural blood pressure changes in Parkinson disease: a randomized crossover study.

Purpose: We investigated the effect of levodopa on postural blood pressure changes in individuals with Parkinson disease (PD) with (PD) and without neurogenic OH (PD).

Methods: We performed a prospective randomized crossover study with autonomic testing performed ON and OFF levodopa. The primary outcome was the change in systolic blood pressure (SBP) from supine to 70° tilt at 3 min (ΔSBP-3').

Global Perceptions and Utilization of Clinical Neurophysiology in Movement Disorders.

Background: Clinical neurophysiology (CNP) involves the use of neurophysiological techniques to make an accurate clinical diagnosis, to quantify the severity, and to measure the treatment response. Despite several studies showing CNP to be a useful diagnostic tool in Movement Disorders (MD), its more widespread utilization in clinical practice has been limited.

Objectives: To better understand the current availability, global perceptions, and challenges for implementation of diagnostic CNP in the clinical practice of MD.

Noninvasive modulation of essential tremor with focused ultrasonic waves.

: Transcranial focused low-intensity ultrasound has the potential to noninvasively modulate confined regions deep inside the human brain, which could provide a new tool for causal interrogation of circuit function in humans. However, it has been unclear whether the approach is potent enough to modulate behavior.: To test this, we applied low-intensity ultrasound to a deep brain thalamic target, the ventral intermediate nucleus, in three patients with essential tremor.

Modulation of motor surround inhibition during motor tasks.

Surround inhibition (SI) in the motor system is important in individuation of actions, but is sometimes difficult to demonstrate. It has also not been evaluated in real life tasks. In this study, we use real life tasks and a new method where excitability of the surround muscle is assessed with respect to its current activity level rather than when it is at rest.

Recognition subtests of the Repeatable Battery for the Assessment of Neuropsychological Status: evidence for a cortical vs. subcortical distinction.

Introduction: Within clinical neuropsychology, a classic diagnostic distinction is made between cortical and subcortical disorders, especially based on their memory profiles. Typically, this is based on the comparison of recall and recognition trials, where individuals with cortical conditions do not tend to benefit (i.e.

Eye-Closure Rate Modulation in Blepharospasm.

Background: Blepharospasm (BSP) is a type of focal dystonia and a number of patients with BSP have relatives also affected by BSP. The objective of this study was to quantify eye closure rates during activities of daily living in individuals with BSP and individuals without BSP with and without a first-degree relative with BSP.

Methods: 37 patients with BSP (BSP group), 10 asymptomatic volunteers with a first-degree relative with BSP (RELATIVES group) and 25 asymptomatic volunteers without relatives with BSP (HV group) were recruited.

Physiology of dystonia: Human studies.

In this chapter, we discuss neurophysiological techniques that have been used in the study of dystonia. We examine traditional disease models such as inhibition and excessive plasticity and review the evidence that these play a causal role in pathophysiology. We then review the evidence for sensory and peripheral influences within pathophysiology and look at an emergent literature that tries to probe how oscillatory brain activity may be linked to dystonia pathophysiology.

Laminar VASO fMRI in focal hand dystonia patients.

Focal Hand Dystonia (FHD) is a disabling movement disorder characterized by involuntary movements, cramps and spasms. It is associated with pathological neural microcircuits in the cortical somatosensory system. While invasive preclinical modalities allow researchers to probe specific neural microcircuits of cortical layers and columns, conventional functional magnetic resonance imaging (fMRI) cannot resolve such small neural computational units.

Video analysis of patients with blepharospasm and lower face dystonias.

Background: Blepharospasm (BSP) is a focal dystonia. There is a lack of standardization in the length of time necessary to get a measure of BSP severity for rating scales.

Objectives: 1) Determine the difference between evaluating the number of eye closures in patients with blepharospasm in 1 vs.

Inter-Individual Variability in Motor Output Is Driven by Recruitment Gain in the Corticospinal Tract Rather Than Motor Threshold.

Variability in the response of individuals to various non-invasive brain stimulation protocols is a major problem that limits their potential for clinical applications. Baseline motor-evoked potential (MEP) amplitude is the key predictor of an individual's response to transcranial magnetic stimulation protocols. However, the factors that predict MEP amplitude and its variability remain unclear.

Eye Movement Disorders in Movement Disorders.

Oculomotor assessment is an essential element of the neurological clinical examination and is particularly important when evaluating patients with movements disorders. Most of the brain is involved in oculomotor control, and thus many neurological conditions present with oculomotor abnormalities. Each of the different classes of eye movements and their features can provide important information that can facilitate differential diagnosis.

Management of Anterocapitis and Anterocollis: A Novel Ultrasound Guided Approach Combined with Electromyography for Botulinum Toxin Injection of Longus Colli and Longus Capitis.

Chemodenervation of cervical musculature using botulinum neurotoxin (BoNT) is established as the gold standard or treatment of choice for management of Cervical Dystonia (CD). The success of BoNT procedures is measured by improved symptomology while minimizing side effects and is dependent upon many factors including: clinical pattern recognition, identifying contributory muscles, BoNT dosage, and locating and safely injecting target muscles. In patients with CD, treatment of anterocollis (forward flexion of the neck) and anterocaput (anterocapitis) (forward flexion of the head) are inarguably challenging.

Self-reported benefit and weakness after botulinum toxin in dystonia.

With this retrospective, single center, chart review study, we investigate the self-reported benefit and weakness after botulinum toxin injections in three different types of dystonia: focal hand dystonia (FHD), blepharospasm and cervical dystonia. We found that the benefit lasts significantly longer in FHD compared to the other two groups.

How to do an electrophysiological study of tremor.

The electrophysiological characterization of hand tremors is a useful method to complement the history and physical exam of tremor patients. Our article describes the methodology (recording, processing and interpretation) used in a diagnostic/phenotypic hand tremor study conducted in our lab at the Human Motor Control Section of the National Institute of Neurological Disorders and Stroke (NINDS), at the National Institutes of Health. The necessary equipment includes two one-axis accelerometers and four-channel electromyography (EMG).

Parietal conditioning enhances motor surround inhibition.

Background: Motor surround inhibition (mSI) is a phenomenon supportive for executing selective finger movements, wherein synergist muscles are selectively facilitated while surround muscles are inhibited. Previous studies of conditioning inputs to several intracortical and cortico-cortical inhibitory networks did not show an influence on mSI. The inhibitory posterior parietal-motor network, which is crucial for executing fine movements, however, has not been studied.

Fatigue induces long-lasting detrimental changes in motor-skill learning.

Fatigue due to physical exertion is a ubiquitous phenomenon in everyday life and especially common in a range of neurological diseases. While the effect of fatigue on limiting skill execution are well known, its influence on learning new skills is unclear. This is of particular interest as it is common practice to train athletes, musicians or perform rehabilitation exercises up to and beyond a point of fatigue.

Reappraising the role of motor surround inhibition in dystonia.

Background: Surround inhibition (SI) in the motor system has been described to be decreased in patients with focal hand dystonia (FHD) but no evidence currently exists for patients with cervical dystonia (CD).

Objective: To characterise the SI profiles in three groups of participants: healthy volunteers, patients with FHD and patients with CD. To provide sample size calculations for future studies.

Cortical inhibitory function in cervical dystonia.

Objective: To assess the specificity of cortical inhibitory deficits in cervical dystonia patients.

Methods: A systematic test battery was developed to assess spatial and temporal aspects of cortical inhibition, in motor and somatosensory systems of the hand. We tested 17 cervical dystonia (CD) patients and 19 controls assessing somatosensory spatial inhibition (grating orientation test, interdigital feedforward subliminal inhibition), somatosensory temporal inhibition (temporal discrimination threshold, feedforward subliminal inhibition), motor spatial inhibition (surround inhibition), and motor temporal inhibition (short interval intracortical inhibition).

Motor training reduces surround inhibition in the motor cortex.

Objective: Surround inhibition (SI) is thought to facilitate focal contraction of a hand muscle by keeping nearby muscles silent. Unexpectedly, SI is reduced in skilled pianists. We tested whether repeated practice of focal contraction in non-pianists could reduce SI.

Task-specific dystonia: pathophysiology and management.

Task-specific dystonia is a form of isolated focal dystonia with the peculiarity of being displayed only during performance of a specific skilled motor task. This distinctive feature makes task-specific dystonia a particularly mysterious and fascinating neurological condition. In this review, we cover phenomenology and its increasingly broad-spectrum risk factors for the disease, critically review pathophysiological theories and evaluate current therapeutic options.