205 research outputs found
Aggression Toward Others Misdiagnosed as Primary Tics
Background: Tics describe a wide range of sudden and repetitive behaviors. Their multifaceted clinical features may resemble other explosive behaviors, including repetitive episodes of aggression toward others (allo-aggression) reported by subjects without tics. Here, we document 3 exemplary cases that help disentangle allo-aggressive behaviors from tics.
Cases: We report 3 cases who presented with an array of complex repetitive behaviors, most notably allo-aggression (eg, sudden kicking, hitting, slapping and biting others, or pushing someone off a bike), which were misdiagnosed as primary tics. In all cases, additional symptoms, such as blackouts, feeling of being controlled by different personalities, or being empowered by repetitive behaviors, and examination pointed toward different neuropsychiatric diagnoses.
Conclusions: Repetitive allo-aggressive behaviors are not part of the range of motor manifestations of tics. This observation not only has important medico-legal implications but is also relevant for the overall perception of Tourette syndrome and other primary tic disorders
Average power and burst analysis revealed complementary information on drug-related changes of motor performance in Parkinson's disease
In patients with Parkinson's disease (PD), suppression of beta and increase in gamma oscillations in the subthalamic nucleus (STN) have been associated with both levodopa treatment and motor functions. Recent results suggest that modulation of the temporal dynamics of theses oscillations (bursting activity) might contain more information about pathological states and behaviour than their average power. Here we directly compared the information provided by power and burst analyses about the drug-related changes in STN activities and their impact on motor performance within PD patients. STN local field potential (LFP) signals were recorded from externalized patients performing self-paced movements ON and OFF levodopa. When normalised across medication states, both power and burst analyses showed an increase in low-beta oscillations in the dopamine-depleted state during rest. When normalised within-medication state, both analyses revealed that levodopa increased movement-related modulation in the alpha and low-gamma bands, with higher gamma activity around movement predicting faster reaches. Finally, burst analyses helped to reveal opposite drug-related changes in low- and high-beta frequency bands, and identified additional within-patient relationships between high-beta bursting and movement performance. Our findings suggest that although power and burst analyses share a lot in common they also provide complementary information on how STN-LFP activity is associated with motor performance, and how levodopa treatment may modify these relationships in a way that helps explain drug-related changes in motor performance. Different ways of normalisation in the power analysis can reveal different information. Similarly, the burst analysis is sensitive to how the threshold is defined - either for separate medication conditions separately, or across pooled conditions. In addition, the burst interpretation has far-reaching implications about the nature of neural oscillations - whether the oscillations happen as isolated burst-events or are they sustained phenomena with dynamic amplitude variations? This can be different for different frequency bands, and different for different medication states even for the same frequency band
StimFit — A Data‐Driven Algorithm for Automated Deep Brain Stimulation Programming
Background: Finding the optimal deep brain stimulation (DBS) parameters from a multitude of possible combinations by trial and error is time consuming and requires highly trained medical personnel.
Objective: We developed an automated algorithm to identify optimal stimulation settings in Parkinson's disease (PD) patients treated with subthalamic nucleus (STN) DBS based on imaging-derived metrics.
Methods: Electrode locations and monopolar review data of 612 stimulation settings acquired from 31 PD patients were used to train a predictive model for therapeutic and adverse stimulation effects. Model performance was then evaluated within the training cohort using cross-validation and on an independent cohort of 19 patients. We inverted the model by applying a brute-force approach to determine the optimal stimulation sites in the target region. Finally, an optimization algorithm was established to identify optimal stimulation parameters. Suggested stimulation parameters were compared to the ones applied in clinical practice.
Results: Predicted motor outcome correlated with observed outcome (R = 0.57, P < 10-10 ) across patients within the training cohort. In the test cohort, the model explained 28% of the variance in motor outcome differences between settings. The stimulation site for maximum motor improvement was located at the dorsolateral border of the STN. When compared to two empirical settings, model-based suggestions more closely matched the setting with superior motor improvement.
Conclusion: We developed and validated a data-driven model that can suggest stimulation parameters leading to optimal motor improvement while minimizing the risk of stimulation-induced side effects. This approach might provide guidance for DBS programming in the future
Effects of subthalamic nucleus deep brain stimulation on emotional working memory capacity and mood in patients with Parkinson's disease
Background: In Parkinson’s disease (PD), cognitive symptoms and mood changes
may be even more distressing for the patient than motor symptoms. Objective:
Our aim was to determine the effects of bilateral subthalamic nucleus deep
brain stimulation (STN-DBS) on working memory (WM) and mood. Methods: Sixteen
patients with PD were assessed with STN-DBS switched on (DBS-ON) and with
dopaminergic treatment (Med-ON) compared to switched off (DBS-OFF) and without
dopaminergic treatment (Med-OFF). The primary outcome measures were a Visual
Analog Mood Scale (VAMS) and an emotional 2-back WM task at 12 months after
DBS in the optimal DBS-ON/Med-ON setting compared to DBS-OFF/Med-OFF. Results:
Comparison of DBS-OFF/Med-OFF to DBS-ON/Med-ON revealed a significant increase
in alertness (meanoff/off =51.59±24.54; meanon/on =72.75; P=0.016) and
contentedness (meanoff/off =38.73±24.41; meanon/on =79.01±17.66; P=0.001,
n=16), and a trend for reduction in sedation (P=0.060), which was related to
stimulation as shown in a subgroup of seven patients. The N-back task revealed
a significant increase in accuracy with DBS-ON/Med-ON compared to DBS-OFF/Med-
OFF (82.0% vs 76.0%, respectively) (P=0.044), regardless of stimulus valence.
Conclusion: In line with previous studies, we found that patients rated
themselves subjectively as more alert, content, and less sedated during short-
term DBS-ON. Accuracy in the WM task increased with the combination of DBS and
medication, possibly related to higher alertness of the patients. Our results
add to the currently mixed results described for DBS on WM and suggest that
there are no deleterious DBS effects on this specific cognitive domain
Long-term effects of bilateral pallidal deep brain stimulation in dystonia: a follow-up between 8 and 16 years
Objective: Observational study to evaluate the long-term motor and non-motor effects of deep brain stimulation (DBS) of the globus pallidus internus (GPi) on medically refractory dystonia.
Background: Dystonia is a chronic disease affecting mainly young patients with a regular life expectancy and lifelong need for therapy. Pallidal DBS is an established treatment for severe isolated dystonia but long-term data are sparse.
Methods: We considered 36 consecutive patients with isolated generalized (n = 14) and cervical/segmental (n = 22) dystonia operated at Charité-University Hospital between 2000 and 2007 in a retrospective analysis for long-term outcome of pallidal DBS. In 19 of these patients, we could analyze dystonic symptoms and disability rated by the Burke–Fahn–Marsden Dystonia Rating scale (BFMDRS) at baseline, short-term (ST-FU, range 3–36 months) and long-term follow-up (LT-FU, range 93–197 months). Quality of life and mood were evaluated using the SF36 and Beck Depression Index (BDI) questionnaires.
Results: Patients reached an improvement in motor symptoms of 63.8 ± 5.7% (mean ± SE) at ST-FU and 67.9 ± 6.1% at LT-FU. Moreover, a significant and stable reduction in disability was shown following DBS (54.2 ± 9.4% at ST-FU and 53.8 ± 9.2% at LT-FU). BDI and SF36 had improved by 40% and 23%, respectively, at LT-FU (n = 14). Stimulation-induced adverse events included swallowing difficulties, dysarthria, and bradykinesia. Pulse generator (n = 3) and electrodes (n = 5) were revised in seven patients due to infection.
Conclusions: Pallidal DBS is a safe and efficacious long-term treatment for dystonia with sustained effects on motor impairment and disability, accompanied by a robust improvement in mood and quality of life
the influence of auditory feedback and deep brain stimulation
Unintentional timing deviations during musical performance can be conceived of
as timing errors. However, recent research on humanizing computer-generated
music has demonstrated that timing fluctuations that exhibit long-range
temporal correlations (LRTC) are preferred by human listeners. This preference
can be accounted for by the ubiquitous presence of LRTC in human tapping and
rhythmic performances. Interestingly, the manifestation of LRTC in tapping
behavior seems to be driven in a subject-specific manner by the LRTC
properties of resting-state background cortical oscillatory activity. In this
framework, the current study aimed to investigate whether propagation of
timing deviations during the skilled, memorized piano performance (without
metronome) of 17 professional pianists exhibits LRTC and whether the structure
of the correlations is influenced by the presence or absence of auditory
feedback. As an additional goal, we set out to investigate the influence of
altering the dynamics along the cortico-basal-ganglia-thalamo-cortical network
via deep brain stimulation (DBS) on the LRTC properties of musical
performance. Specifically, we investigated temporal deviations during the
skilled piano performance of a non-professional pianist who was treated with
subthalamic-deep brain stimulation (STN-DBS) due to severe Parkinson's
disease, with predominant tremor affecting his right upper extremity. In the
tremor-affected right hand, the timing fluctuations of the performance
exhibited random correlations with DBS OFF. By contrast, DBS restored long-
range dependency in the temporal fluctuations, corresponding with the general
motor improvement on DBS. Overall, the present investigations demonstrate the
presence of LRTC in skilled piano performances, indicating that unintentional
temporal deviations are correlated over a wide range of time scales. This
phenomenon is stable after removal of the auditory feedback, but is altered by
STN-DBS, which suggests that cortico-basal ganglia-thalamocortical circuits
play a role in the modulation of the serial correlations of timing
fluctuations exhibited in skilled musical performance
Less Is More – Estimation of the Number of Strides Required to Assess Gait Variability in Spatially Confined Settings
Background: Gait variability is an established marker of gait function that can be assessed using sensor-based approaches. In clinical settings, spatial constraints and patient condition impede the execution of longer distance walks for the recording of gait parameters. Turning paradigms are often used to overcome these constraints and commercial gait analysis systems algorithmically exclude turns for gait parameters calculations. We investigated the effect of turns in sensor-based assessment of gait variability.Methods: Continuous recordings from 31 patients with movement disorders (ataxia, essential tremor and Parkinson’s disease) and 162 healthy elderly (HE) performing level walks including 180° turns were obtained using an inertial sensor system. Accuracy of the manufacturer’s algorithm of turn-detection was verified by plotting stride time series. Strides before and after turn events were extracted and compared to respective average of all strides. Coefficient of variation (CoV) of stride length and stride time was calculated for entire set of strides, segments between turns and as cumulative values. Their variance and congruency was used to estimate the number of strides required to reliably assess the magnitude of stride variability.Results: Non-detection of turns in 5.8% of HE lead to falsely increased CoV for these individuals. Even after exclusion of these, strides before/after turns tended to be spatially shorter and temporally longer in all groups, contributing to an increase of CoV at group level and widening of confidence margins with increasing numbers of strides. This could be attenuated by a more generous turn excision as an alternative approach. Correlation analyses revealed excellent consistency for CoVs after at most 20 strides in all groups. Respective stride counts were even lower in patients using a more generous turn excision.Conclusion: Including turns to increase continuous walking distance in spatially confined settings does not necessarily improve the validity and reliability of gait variability measures. Specifically with gait pathology, perturbations of stride characteristics before/after algorithmically excised turns were observed that may increase gait variability with this paradigm. We conclude that shorter distance walks of around 15 strides suffice for reliable and valid recordings of gait variability in the groups studied here
Deep brain stimulation reduces (nocturnal) dyskinetic exacerbations in patients with ADCY5 mutation: a case series
Mutations in the ADCY5 gene can cause a complex hyperkinetic movement disorder. Episodic exacerbations of dyskinesia are a particularly disturbing symptom as they occur predominantly during night and interrupt sleep. We present the clinical short- and long-term effects of pallidal deep brain stimulation (DBS) in three patients with a confirmed pathogenic ADCY5 mutation. Patients were implanted with bilateral pallidal DBS at the age of 34, 20 and 13 years. Medical records were reviewed for clinical history. Pre- and postoperative video files were assessed using the “Abnormal Involuntary Movement Scale” (AIMS) as well as the motor part of the “Burke Fahn Marsden Dystonia Rating Scale” (BFMDRS). All patients reported subjective general improvement ranging from 40 to 60%, especially the reduction of nocturnal episodic dyskinesias (80–90%). Objective scales revealed only a mild decrease of involuntary movements in all and reduced dystonia in one patient. DBS-induced effects were sustained up to 13 years after implantation. We demonstrate that treatment with pallidal DBS was effective in reducing nocturnal dyskinetic exacerbations in patients with ADCY5-related movement disorder, which was sustained over the long term
Long‐term effects of pallidal and thalamic deep brain stimulation in myoclonus dystonia
Objective: Observational study to evaluate long-term effects of deep brain stimulation (DBS) of the globus pallidus internus (GPi) and the ventral intermediate thalamic nucleus (VIM) on patients with medically refractory myoclonus dystonia (MD).
Background: More recently, pallidal as well as thalamic DBS have been applied successfully in MD but long-term data are sparse.
Methods: We retrospectively analyzed a cohort of seven MD patients with either separate (n = 1, VIM) or combined GPi- DBS and VIM-DBS (n = 6). Myoclonus, dystonia and disability were rated at baseline (BL), short-term (ST-FU) and long-term follow-up (LT-FU) using the United Myoclonus Rating Scale, Burke-Fahn-Marsden Dystonia Rating Scale (BFMDRS) and Tsui rating scale, respectively. Quality of life (QoL) and mood were evaluated using the SF-36 and Beck Depression Inventory questionnaires, respectively.
Results: Patients reached a significant reduction of myoclonus at ST-FU (62% ± 7.3%; mean ± SE) and LT-FU (68% ± 3.4%). While overall motor BFMDRS changes were not significant at LT-FU, patients with GPi-DBS alone responded better and predominant cervical dystonia ameliorated significantly up to 54% ± 9.7% at long-term. Mean disability scores significantly improved by 44% ± 11.4% at ST-FU and 58% ± 14.8% at LT-FU. Mood and QoL remained unchanged between 5 and up to 20 years postoperatively. No serious long-lasting stimulation-related adverse events were observed.
Conclusions: We present a cohort of MD patients with very long follow-up of pallidal and/or thalamic DBS that supports the GPi as the favourable stimulation target in MD with safe and sustaining effects on motor symptoms (myoclonus>dystonia) and disability
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