Successful MRI-Guided Focused Ultrasound Thalamotomy after Ipsilateral Gamma Knife Radiosurgery for Essential Tremor: A Case Report with Video.

We report the case of a 67-year-old left-handed female patient with disabling medically refractory essential tremor who underwent successful right-sided magnetic resonance-guided focused ultrasound (MRgFUS) of the ventral intermediate nucleus after ipsilateral gamma knife radiosurgery (GKRS) thalamotomy performed 3 years earlier. The GKRS had a partial effect on her postural tremor without side effects, but there was no reduction of her kinetic tremor or improvement in her quality of life (QoL). The patient subsequently underwent a MRgFUS thalamotomy, which induced an immediate and marked reduction in both the postural and kinetic tremor components, with minor complications (left upper lip hypesthesia, dysmetria in her left hand, and slight gait ataxia). The MRgFUS-induced lesion was centered more medially than the GKRS-induced lesion and extended more posteriorly and inferiorly. The MRgFUS-induced lesion interrupted remaining fibers of the dentatorubrothalamic tract (DRTT). The functional improvement 1-year post-MRgFUS was significant due to a marked reduction of the patient's kinetic tremor. The QoL score (Quality of Life in Essential Tremor) improved by 88% and her Clinical Rating Scale for Tremor left hand score by 62%. The side effects persisted but were minor, with no impact on her QoL. The explanation for the superior efficacy of MRgFUS compared to GKRS in our patient could be due to either a poor response to the GKRS or to a better localization of the MRgFUS lesion with a more extensive interruption of DRTT fibers. In conclusion, MRgFUS can be a valuable therapeutic option after unsatisfactory GKRS, especially because MRgFUS has immediate clinical effectiveness, allowing intra-procedural test lesions and possible readjustment of the target if necessary.

Complex movement disorder in a patient with heterozygous YY1 mutation (Gabriele-de Vries syndrome).

YY1 mutations cause Gabriele-de Vries syndrome, a recently described condition involving cognitive impairment, facial dysmorphism and intrauterine growth restriction. Movement disorders were reported in 5/10 cases of the original series, but no detailed description was provided. Here we present a 21-year-old woman with a mild intellectual deficit, facial dysmorphism and a complex movement disorder including an action tremor, cerebellar ataxia, dystonia, and partial ocular apraxia as the presenting and most striking feature. Whole-exome sequencing revealed a novel heterozygous de novo mutation in YY1 [NM: 003403.4 (YY1): c.907 T > C; p.(Cys303Arg)], classified as pathogenic according to the ACMG guidelines.

Ambulatory monitoring of physical activities in patients with Parkinson's disease.

A new ambulatory method of monitoring physical activities in Parkinson's disease (PD) patients is proposed based on a portable data-logger with three body-fixed inertial sensors. A group of ten PD patients treated with subthalamic nucleus deep brain stimulation (STN-DBS) and ten normal control subjects followed a protocol of typical daily activities and the whole period of the measurement was recorded by video. Walking periods were recognized using two sensors on shanks and lying periods were detected using a sensor on trunk. By calculating kinematics features of the trunk movements during the transitions between sitting and standing postures and using a statistical classifier, sit-to-stand (SiSt) and stand-to-sit (StSi) transitions were detected and separated from other body movements. Finally, a fuzzy classifier used this information to detect periods of sitting and standing. The proposed method showed a high sensitivity and specificity for the detection of basic body postures allocations: sitting, standing, lying, and walking periods, both in PD patients and healthy subjects. We found significant differences in parameters related to SiSt and StSi transitions between PD patients and controls and also between PD patients with and without STN-DBS turned on. We concluded that our method provides a simple, accurate, and effective means to objectively quantify physical activities in both normal and PD patients and may prove useful to assess the level of motor functions in the latter.

Gait assessment in Parkinson's disease: toward an ambulatory system for long-term monitoring.

An ambulatory gait analysis method using body-attached gyroscopes to estimate spatio-temporal parameters of gait has been proposed and validated against a reference system for normal and pathologic gait. Later, ten Parkinson's disease (PD) patients with subthalamic nucleus deep brain stimulation (STN-DBS) implantation participated in gait measurements using our device. They walked one to three times on a 20-m walkway. Patients did the test twice: once STN-DBS was ON and once 180 min after turning it OFF. A group of ten age-matched normal subjects were also measured as controls. For each gait cycle, spatio-temporal parameters such as stride length (SL), stride velocity (SV), stance (ST), double support (DS), and gait cycle time (GC) were calculated. We found that PD patients had significantly different gait parameters comparing to controls. They had 52% less SV, 60% less SL, and 40% longer GC. Also they had significantly longer ST and DS (11% and 59% more, respectively) than controls. STN-DBS significantly improved gait parameters. During the stim ON period, PD patients had 31% faster SV, 26% longer SL, 6% shorter ST, and 26% shorter DS. GC, however, was not significantly different. Some of the gait parameters had high correlation with Unified Parkinson's Disease Rating Scale (UPDRS) subscores including SL with a significant correlation (r = -0.90) with UPDRS gait subscore. We concluded that our method provides a simple yet effective way of ambulatory gait analysis in PD patients with results confirming those obtained from much more complex and expensive methods used in gait labs.

[Kinesiologic analysis of gait and abnormal movements]. / Analyse cinésiologique de la marche et des mouvements anormaux.

Gait disorders, postural instability and movement disorders, such as tremor, chorea or dystonia, are common complaints in day-to-day neurological practice. These conditions are quite difficult to appreciate objectively when relying on clinical observation only, yet a correct assessment of their phenomenology and an accurate measurement of their main characteristics are required to address the questions of both the underlying diagnosis and the functional impairment they may generate. By contrast, kinesiological analyses allow qualitative and quantitative studies of gait, posture and movements and may lead to specific therapeutic interventions. kinesiological analyses, which requires a high-technology laboratory conducted by a trained staff, is based on the sequential or simultaneous use of various and complementary measurement methods, whose choice is problem-oriented. Hence, the use of specific observational analysis, three-dimensional kinematic recordings, poly-electromyography and electro goniometry for the analysis of gait, the use of force plate for the analysis of postural stability and the use of electromyography and multiaxial accelerometers or gyroscopes for the analysis of movement disorders. In the present article, we review the particular features of these measurement tools and the clinical usefulness of their routine use illustrated by case reports.