The gait disorder in primary orthostatic tremor

Association Between Dynapenia/Sarcopenia, Extrapyramidal Symptoms, Negative Symptoms, Body Composition, and Nutritional Status in Patients with Chronic Schizophrenia

Background/Objectives: This study aimed to determine the association between chronic schizophrenia, extrapyramidal symptoms (EPSs), body composition, nutritional status, and dynapenia/sarcopenia. Methods: Data from 68 chronic patients with schizophrenia were analyzed using Spearman's rho correlation coefficients, Kruskal-Wallis test, Mann-Whitney U test, and Cramér's V statistics. Results: Among the participants, 32.4% had no loss of muscle mass or function, 39.7% had dynapenia, and 27.9% had sarcopenia. This study identified five key findings: (1) Bilateral grip strength, skeletal muscle index, and walking speed are interrelated, with higher negative symptom scores linked to slower movement and rigidity, particularly in the sarcopenia group, indicating that negative symptoms may contribute to muscle weakness and progression to sarcopenia. (2) Increasing age is associated with a decrease in chlorpromazine equivalent dose and an increase in the severity of EPSs. (3) Blood urea nitrogen (BUN)/creatinine ratio and all sarcopenia risk indicators were significantly negatively correlated. (4) Dynapenia and sarcopenia groups exhibited significant differences in muscle mass and nutritional status compared to the non-penia group, including reduced muscle mass, lower basal metabolic rate, and lower visceral fat levels. (5) There was an association between the Barthel Index (BI) score for activities of daily living (ADL) and dynapenia/sarcopenia. Particularly with regard to ADL, it seems necessary to pay attention to muscle weakness in partially independent patients who score 60 points or more. Conclusions: BUN/creatinine ratio, BI, EPSs, body mass index, grip strength, total protein, and albumin were useful indicators for detecting the risk of dynapenia/sarcopenia in routine psychiatric care.

Consensus Paper: Ataxic Gait

The aim of this consensus paper is to discuss the roles of the cerebellum in human gait, as well as its assessment and therapy. Cerebellar vermis is critical for postural control. The cerebellum ensures the mapping of sensory information into temporally relevant motor commands. Mental imagery of gait involves intrinsically connected fronto-parietal networks comprising the cerebellum. Muscular activities in cerebellar patients show impaired timing of discharges, affecting the patterning of the synergies subserving locomotion. Ataxia of stance/gait is amongst the first cerebellar deficits in cerebellar disorders such as degenerative ataxias and is a disabling symptom with a high risk of falls. Prolonged discharges and increased muscle coactivation may be related to compensatory mechanisms and enhanced body sway, respectively. Essential tremor is frequently associated with mild gait ataxia. There is growing evidence for an important role of the cerebellar cortex in the pathogenesis of essential tremor. In multiple sclerosis, balance and gait are affected due to cerebellar and spinal cord involvement, as a result of disseminated demyelination and neurodegeneration impairing proprioception. In orthostatic tremor, patients often show mild-to-moderate limb and gait ataxia. The tremor generator is likely located in the posterior fossa. Tandem gait is impaired in the early stages of cerebellar disorders and may be particularly useful in the evaluation of pre-ataxic stages of progressive ataxias. Impaired inter-joint coordination and enhanced variability of gait temporal and kinetic parameters can be grasped by wearable devices such as accelerometers. Kinect is a promising low cost technology to obtain reliable measurements and remote assessments of gait. Deep learning methods are being developed in order to help clinicians in the diagnosis and decision-making process. Locomotor adaptation is impaired in cerebellar patients. Coordinative training aims to improve the coordinative strategy and foot placements across strides, cerebellar patients benefiting from intense rehabilitation therapies. Robotic training is a promising approach to complement conventional rehabilitation and neuromodulation of the cerebellum. Wearable dynamic orthoses represent a potential aid to assist gait. The panel of experts agree that the understanding of the cerebellar contribution to gait control will lead to a better management of cerebellar ataxias in general and will likely contribute to use gait parameters as robust biomarkers of future clinical trials.

The Phenomenology of Primary Orthostatic Tremor

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