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Neurology AND Movement disorders [keywords]
- The Rationale Driving the Evolution of Deep Brain Stimulation to Constant-Current Devices. [JOURNAL ARTICLE]
- Neuromodulation 2014 Aug 29.
Deep brain stimulation (DBS) is an effective therapy for the treatment of a number of movement and neuropsychiatric disorders. The effectiveness of DBS is dependent on the density and location of stimulation in a given brain area. Adjustments are made to optimize clinical benefits and minimize side effects. Until recently, clinicians would adjust DBS settings using a voltage mode, where the delivered voltage remained constant. More recently, a constant-current mode has become available where the programmer sets the current and the stimulator automatically adjusts the voltage as impedance changes.We held an expert consensus meeting to evaluate the current state of the literature and field on constant-current mode versus voltage mode in clinical brain-related applications.There has been little reporting of the use of constant-current DBS devices in movement and neuropsychiatric disorders. However, as impedance varies considerably between patients and over time, it makes sense that all new devices will likely use constant current.
- Plasma melatonin is reduced in Huntington's disease. [JOURNAL ARTICLE]
- Mov Disord 2014 Aug 27.
This study was undertaken to determine whether the production of melatonin, a hormone regulating sleep in relation to the light/dark cycle, is altered in Huntington's disease. We analyzed the circadian rhythm of melatonin in a 24-hour study of cohorts of control, premanifest, and stage II/III Huntington's disease subjects. The mean and acrophase melatonin concentrations were significantly reduced in stage II/III Huntington's disease subjects compared with controls. We also observed a nonsignificant trend toward reduced mean and acrophase melatonin in premanifest Huntington's disease subjects. Onset of melatonin rise was significantly more temporally spread in both premanifest and stage II/III Huntington's disease subjects compared with controls. A nonsignificant trend also was seen for reduced pulsatile secretion of melatonin. Melatonin concentrations are reduced in Huntington's disease. Altered melatonin patterns may provide an explanation for disrupted sleep and circadian behavior in Huntington's disease, and represent a biomarker for disease state. Melatonin therapy may help the sleep disorders seen in Huntington's disease. © 2014 The Authors. Movement Disorders published by Wiley Periodicals, Inc. on behalf of International Parkinson and Movement Disorder Society.
- Phenotypic variability of PINK1 expression: 12 Years' clinical follow-up of two Italian families. [JOURNAL ARTICLE]
- Mov Disord 2014 Aug 27.
Mutations in the PINK1 gene are the second most frequent cause of autosomal recessive early-onset parkinsonism.We evaluated five affected PINK1 homozygous and 14 heterozygous mutation carriers from two large Italian families over a 12-year follow-up period. Motor, nonmotor, cognitive, psychiatric, and behavioral profiles were systematically assessed. Four homozygotes and eight heterozygotes underwent magnetic resonance imaging.All homozygotes showed a mild progression of motor signs and a persistent excellent response to levodopa. All but one patient complained of nonmotor symptoms and sleep impairment. Three presented impulse control disorders and two anxiety and apathy. All obtained abnormal scores at Montreal Cognitive Assessment (MoCA) and in tests sensitive to frontal functions; one presented a global cognitive impairment. Three heterozygotes showed motor signs and were diagnosed as possibly affected. They had nonmotor symptoms and cognitive impairment, and two of them showed mild bilateral temporal atrophy. Five unaffected heterozygotes reported abnormal scores at MoCA and low performances at tests sensitive to frontal functions.We expanded the phenotypic profile of PINK1-related parkinsonism, including psychiatric and cognitive features as part of clinical presentation. © 2014 International Parkinson and Movement Disorder Society.
- Loss of sensory attenuation in patients with functional (psychogenic) movement disorders. [JOURNAL ARTICLE]
- Brain 2014 Aug 26.
Functional movement disorders require attention to manifest yet patients report the abnormal movement to be out of their control. In this study we explore the phenomenon of sensory attenuation, a measure of the sense of agency for movement, in this group of patients by using a force matching task. Fourteen patients and 14 healthy control subjects were presented with forces varying from 1 to 3 N on the index finger of their left hand. Participants were required to match these forces; either by pressing directly on their own finger or by operating a robot that pressed on their finger. As expected, we found that healthy control subjects consistently overestimated the force required when pressing directly on their own finger than when operating a robot. However, patients did not, indicating a significant loss of sensory attenuation in this group of patients. These data are important because they demonstrate that a fundamental component of normal voluntary movement is impaired in patients with functional movement disorders. The loss of sensory attenuation has been correlated with the loss of sense of agency, and may help to explain why patients report that they do not experience the abnormal movement as voluntary.
- Fatal Human Herpesvirus 6-Associated Encephalitis in Two Boys With Underlying POLG Mitochondrial Disorders. [Journal Article]
- Pediatr Neurol 2014 Sep; 51(3):448-52.
Human herpesvirus 6 is a significant cause of the febrile illness roseola infantum in young children. Infection with human herpesvirus 6 typically causes a self-limited febrile illness but occasionally is associated with central nervous system manifestations, including febrile seizures and encephalitis. Host factors associated with severe manifestations of human herpesvirus 6-associated neurological disease remain poorly characterized.We report two previously healthy young boys with human herpesvirus 6-associated encephalitis who developed a progressive, and ultimately fatal, encephalopathy with refractory movement disorder concurrent with acquisition of acute human herpesvirus 6 infection. Both children were treated with the antiviral ganciclovir without improvement of their neurological symptoms, although quantitative human herpesvirus 6 polymerase chain reaction of cerebrospinal fluid and/or blood confirmed a decline in viral load with treatment. The clinical course in both cases was most consistent with Alpers-Huttenlocher syndrome, given the intractable seizures, developmental regression, and, ultimately, death due to liver and renal failure. In support of this, postmortem analysis identified both children to be compound heterozygous for mutations in the mitochondrial polymerase γ gene, POLG.POLG mutations are associated with Alpers-Huttenlocher syndrome; however, no prior studies have examined the role of acute human herpesvirus 6 infection in these patients presenting with severe neurological disease. It is possible the POLG mutation phenotype was unmasked and/or exacerbated by human herpesvirus 6 infection in these two patients, potentially contributing to a more rapid clinical deterioration. This report provides new insight into a previously unrecognized association between POLG mutations and poor neurological outcome after human herpesvirus 6 infection.
- How many people in the USA have essential tremor? Deriving a population estimate based on epidemiological data. [Journal Article]
- Tremor Other Hyperkinet Mov (N Y) 2014.:259.
Essential tremor (ET) is often reported to be among the most prevalent movement disorders, yet the precise number of cases in the USA is not known. The goal of the current analyses was to use published data from epidemiological studies to derive an estimate of the number of people currently residing in the USA who have ET.A PubMed search was conducted to identify population-based prevalence studies of ET. The methodology of 34 identified studies was assessed. Then the three most methodologically rigorous studies were selected, and age-specific prevalence data were abstracted. US census data from 2012 were used to determine the population in the USA by 10-year age categories.Using data from three studies, estimates of the number of ET cases (2012) ranged from 6.38 to 7.63 million (mean = 7.01 million). This corresponds to approximately 2.2% of the US population.Knowing the number of ET cases in the USA is important in terms of estimating the medical burden on communities and society, and providing an objective metric on which to base health resource planning.
- Difficult morning awakening from rapid eye movement sleep and impaired cognitive function in delayed sleep phase disorder patients. [JOURNAL ARTICLE]
- Sleep Med 2014 Jul 3.
Difficult awakening is a key symptom of delayed sleep phase disorder (DSPD), but no studies have quantified awakening thresholds in a sleep laboratory. This study assessed whether cognitive function was impaired after awakening and whether difficult awakening was associated with specific polysomnographic features such as slow wave sleep stage N3.Nine patients with DSPD and nine sex- and age-matched healthy controls were included. Polysomnography was performed at our university hospital from midnight. An alarm clock was activated at 07:00 with sound intensity increasing from 72 to 104 dB. Participants performed a continuous performance test (CPT) the previous afternoon and immediately upon awakening.Three DSPD patients and zero controls did not wake up to the maximum 104 dB alarm sound; all three patients were in rapid eye movement (REM) sleep when the alarm clock went off (difference in proportions, P = 0.047). In patients, CPT reaction time was prolonged in the morning compared to the afternoon [analysis of variance (ANOVA) interaction, P = 0.01]. DSPD patients made more omission errors than controls regardless of time of the day (ANOVA main effect, P = 0.046).Difficult awakening from slow wave sleep was not observed. A subgroup of DSPD patients may have a severe problem waking up from REM sleep. DSPD patients may also have a state-like impairment in cognitive function in the morning and a trait-like impairment not depending on time of day, compared to normal sleepers.
- Predominant endothelial vasomotor activity during human sleep: a near-infrared spectroscopy study. [JOURNAL ARTICLE]
- Eur J Neurosci 2014 Aug 26.
Vasomotion is important in the study of vascular disorders, including stroke. Spontaneous low and very low hemodynamic oscillations (3-150 mHz) measured with near-infrared spectroscopy (NIRS) reflect the endothelial (3-20 mHz), neurogenic (20-40 mHz) and myogenic (40-150 mHz) components of vasomotion. We investigated sleep-specific patterns of vasomotion by characterizing hemodynamic oscillations with NIRS in healthy subjects, and tested the feasibility of NIRS as a bedside tool for monitoring vasomotion during whole-night sleep. To characterize local cerebral vasomotion, we compared cerebral NIRS measurements with muscular NIRS measurements and peripheral arterial oxygen saturation (SpO2 ) during different sleep stages in 14 healthy volunteers. Spectral powers of hemodynamic oscillations in the frequency range of endothelial vasomotion were systemically predominant in every sleep stage, and the powers of endothelial and neurogenic vasomotion decreased in deep sleep as compared with light sleep and rapid eye movement (REM) sleep in brain, muscle, and SpO2 . The decrease in the powers of myogenic vasomotion in deep sleep only occurred in brain, and not in muscle. These results point to a predominant role of endothelial function in regulating vasomotion during sleep. The decline in cerebral endothelial and neurogenic vasomotion during progression to deeper non-REM sleep suggests that deep sleep may play a protective role for vascular function. NIRS can be used to monitor endothelial control of vasomotion during nocturnal sleep, thus providing a promising non-invasive bedside tool with which to study the sleep-relevant pathological mechanisms in vascular diseases and stroke.
- Patient-specific determinants of responsiveness to robot-enhanced treadmill therapy in children and adolescents with cerebral palsy. [JOURNAL ARTICLE]
- Dev Med Child Neurol 2014 Aug 25.
The aim of the study was to evaluate patient-specific determinants of responsiveness to robot-enhanced repetitive treadmill therapy (ROBERT) in patients with early-developed movement disorders.Patients were treated over 12 sessions during a 3-week period. Gross Motor Function Measure-66 (GMFM-66) scores 1 day before ROBERT were compared with scores recorded 1 day after ROBERT. The association of GMFM-66 baseline score, age, sex, aetiology, and add-on botulinum toxin therapy to response to treatment was assessed.Eighty-three patients aged between 4 and 18 years (48 males, 35 females; mean age 10y 8mo, SD 6y 1mo; Gross Motor Function Classification System level I [n=12], II [n=21], III [n=35], IV [n=10], and V [n=1]) were each treated for a total of 7.2 (SD 1.9) treadmill walking hours. Aetiology was bilateral spastic cerebral palsy (BS-CP; n=69), unilateral CP (n=3), ataxic CP (n=3), hereditary spastic paraparesis (n=6), and genetic syndrome including spasticity (n=2). Meaningful improvements were observed in GMFM-66 (+2.5; 95% CI 2.0-3.0), GMFM-D (+5.2; 95% CI 3.6-6.8), and GMFM-E (+4.0; 95% CI 2.8-5.3). There was a high inter-individual variability in treatment response. After multivariable adjustment, the improvements in GMFM-66 and GMFM-E scores were positively associated with the GMFM-66 baseline score. The effect on GMFM-D improvement was inversely associated with age.Gross motor abilities at baseline and age were identified as relevant determinants for the high degree of interpersonal variability in response to ROBERT.
- Increased Pediatric Functional Neurological Symptom Disorders After the Boston Marathon Bombings: A Case Series. [JOURNAL ARTICLE]
- Pediatr Neurol 2014 Jul 19.
Functional neurological symptom disorders are frequently the basis for acute neurological consultation. In children, they are often precipitated by high-frequency everyday stressors. The extent to which a severe traumatic experience may also precipitate functional neurological abnormalities is unknown.For the 2-week period after the Boston Marathon bombings, we prospectively collected data on patients whose presentation suggested a functional neurological symptom disorder. We assessed clinical and demographic variables, duration of symptoms, extent of educational impact, and degree of connection to the Marathon bombing. We contacted all patients at 6 months after presentation to determine the outcome and accuracy of the diagnosis.In a parallel study, we reported a baseline of 2.6 functional neurological presentations per week in our emergency room. In the week after the Marathon bombings, this frequency tripled. Ninety-one percent of presentations were delayed by 1 week, with onset around the first school day after a city-wide lockdown. Seventy-three percentage had a history of a prior psychiatric diagnosis. At the 6 months follow-up, no functional neurological symptom disorder diagnoses were overturned and no new organic diagnosis was made.Pediatric functional neurological symptom disorder may be precipitated by both casual and high-intensity stressors. The 3.4-fold increase in incidence after the Boston Marathon bombings and city-wide lockdown demonstrates the marked effect that a community-wide tragedy can have on the mental health of children. Care providers must be aware of functional neurological symptom disorders after stressful community events in vulnerable patient populations, particularly those with prior psychiatric diagnoses.