Publications by authors named "Carine Karachi"

Objective: To investigate the effects of directional subthalamic deep brain stimulation (STN-dDBS) on gait and balance disorders, including freezing of gait (FOG), in patients with advanced Parkinson's disease (PD).

Methods: We included 10 participants who underwent STN-DBS and presented severe preoperative FOG, in a randomized, double-blind, crossover study. We used segmented DBS electrodes to investigate whether directing the predicted volume of tissue activated (VTA) to overlap the central STN preferentially improved gait and balance disorders compared to directional DBS applied in the more posterior STN (sensorimotor).

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Background And Purpose: Disabling dystonia despite optimal medical treatment is common in Wilson disease (WD). No controlled study has evaluated the effect of deep brain stimulation (DBS) on dystonia related to WD. This study was undertaken to evaluate the efficacy of DBS on dystonia related to WD.

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Article Synopsis
  • * It found that GTS patients exhibited higher firing rates and burst activity, while DYS patients showed more pauses and burst frequency, highlighting distinct neuronal activity patterns between the two disorders.
  • * The research suggests a need for further studies on neuronal behavior in the GPi to improve DBS techniques and tailor treatments for better clinical outcomes in patients with hyperkinetic movement disorders.
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Background: Deep brain stimulation (DBS) is a highly efficient, evidence-based therapy to alleviate symptoms and improve quality of life in movement disorders such as Parkinson's disease, essential tremor, and dystonia, which is also being applied in several psychiatric disorders, such as obsessive-compulsive disorder and depression, when they are otherwise resistant to therapy.

Summary: At present, DBS is clinically applied in the so-called open-loop approach, with fixed stimulation parameters, irrespective of the patients' clinical state(s). This approach ignores the brain states or feedback from the central nervous system or peripheral recordings, thus potentially limiting its efficacy and inducing side effects by stimulation of the targeted networks below or above the therapeutic level.

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Effective neural stimulation for the treatment of severe psychiatric disorders needs accurate characterisation of surgical targets. This is especially true for the medial subthalamic region (MSR) which contains three targets: the anteromedial STN for obsessive compulsive disorder (OCD), the medial forebrain bundle (MFB) for depression and OCD, and the "Sano triangle" for pathological aggressiveness. Blocks containing the subthalamic area were obtained from two human brains.

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Aims: The distinction between CNS WHO grade 2 and grade 3 is instrumental in choosing between observational follow-up and adjuvant treatment for resected astrocytomas IDH-mutant. However, the criteria of CNS WHO grade 2 vs 3 have not been updated since the pre-IDH era.

Methods: Maximal mitotic activity in consecutive high-power fields corresponding to 3 mm was examined for 118 lower-grade astrocytomas IDH-mutant.

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Crack-cocaine dependence is a severe condition with a high mortality rate. This single case study report details the first deep brain stimulation (DBS) trial targeting the sub-thalamic nucleus (STN) for crack-cocaine dependence. The investigation aimed to assess the effects of STN-DBS on cocaine craving and cocaine use, as well as STN-DBS safety and tolerance in this indication.

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Essential tremor (ET) is a disabling condition resulting from a dysfunction of cerebello-thalamo-cortical circuitry. Deep brain stimulation (DBS) or lesion of the ventral-intermediate thalamic nucleus (VIM) is an effective treatment for severe ET. Transcranial cerebellar brain stimulation has recently emerged as a non-invasive potential therapeutic option.

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Article Synopsis
  • * Researchers used tractography to analyze brain connectivity in 58 TS patients compared to 35 healthy controls, revealing heightened connectivity in specific limbic areas, particularly the left medial subthalamic region.
  • * The study found that abnormal connectivity with the insular cortex is linked to increased impulsivity and anxiety in TS patients, suggesting that these neurobiological factors contribute to the disorder's psychiatric symptoms.
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Introduction: Subthalamic deep-brain-stimulation (STN-DBS) is an effective means to treat Parkinson's disease (PD) symptoms. Its benefit on gait disorders is variable, with freezing of gait (FOG) worsening in about 30% of cases. Here, we investigate the clinical and anatomical features that could explain post-operative FOG.

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Background: The subthalamic nucleus (STN) is an effective neurosurgical target to improve motor symptoms in Parkinson's Disease (PD) patients. MR-guided Focused Ultrasound (MRgFUS) subthalamotomy is being explored as a therapeutic alternative to Deep Brain Stimulation (DBS) of the STN. The hyperdirect pathway provides a direct connection between the cortex and the STN and is likely to play a key role in the therapeutic effects of MRgFUS intervention in PD patients.

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Introduction: Deep brain stimulation (DBS) of the mesencephalic locomotor region, composed of the pedunculopontine (PPN) and cuneiform (CuN) nuclei, has been proposed to treat dopa-resistant gait and balance disorders in Parkinson's disease (PD). Here, we report the long-term effects of PPN- or CuN-DBS on these axial disorders.

Methods: In 6 PD patients operated for mesencephalic locomotor region DBS and prospectively followed for more than 2 years, we assessed the effects of both PPN- and CuN-DBS (On-dopa) in a cross-over single-blind study by using clinical scales and recording gait parameters.

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Background: Dopa-resistant freezing of gait (FOG) and falls represent the dominant motor disabilities in advanced Parkinson's disease (PD).

Objective: We investigate the effects of deep brain stimulation (DBS) of the mesencephalic locomotor region (MLR), comprised of the pedunculopontine (PPN) and cuneiform (CuN) nuclei, for treating gait and balance disorders, in a randomized double-blind cross-over trial.

Methods: Six PD patients with dopa-resistant FOG and/or falls were operated for MLR-DBS.

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In 2011 the European Society for the Study of Tourette Syndrome (ESSTS) published its first European clinical guidelines for the treatment of Tourette Syndrome (TS) with part IV on deep brain stimulation (DBS). Here, we present a revised version of these guidelines with updated recommendations based on the current literature covering the last decade as well as a survey among ESSTS experts. Currently, data from the International Tourette DBS Registry and Database, two meta-analyses, and eight randomized controlled trials (RCTs) are available.

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A critical mechanism for maximizing reward is instrumental learning. In standard instrumental learning models, action values are updated on the basis of reward prediction errors (RPEs), defined as the discrepancy between expectations and outcomes. A wealth of evidence across species and experimental techniques has established that RPEs are signaled by midbrain dopamine neurons.

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Obsessive-compulsive disorder (OCD) is a widespread chronic neuropsychiatric disorder characterized by recurrent intrusive thoughts, images, or urges (obsessions) that typically cause anxiety or distress. Even when optimal treatment is provided, 10% of patients remain severely affected chronically. In some countries, deep brain stimulation (DBS) is an approved and effective therapy for patients suffering from treatment-resistant OCD.

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Background: Mutations in TUBB4A are associated with a wide phenotypic spectrum including generalized dystonia with whispering dysphonia (DYT-TUBB4A).

Methods: We report the case of a 44-year-old patient with DYT-TUBB4A with a clinical presentation of disabling progressive dystonia, with a prominent laryngeal, cervical and facial involvement.

Results: Bipallidal deep brain stimulation (DBS) resulted in a 55% reduction of dystonia severity assessed by the Burke-Fahn-Marsden scale score 6 months after surgery.

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Background: Subthalamic nucleus (STN) deep brain stimulation alleviates obsessive-compulsive disorder (OCD) symptoms, suggesting that this basal ganglia structure may play a key role in integrating limbic and motor information. We explored the modulation of STN neural activity by visual emotional information under different motor demands.

Methods: We compared STN local field potentials acquired in 7 patients with OCD and 15 patients with Parkinson's disease off and on levodopa while patients categorized pictures as unpleasant, pleasant, or neutral and pressed a button for 1 of these 3 categories depending on the instruction.

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