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Traditionally conceived of and studied as a disorder of cognitive and emotional functioning, schizophrenia (SZ) is also characterized by alterations in bodily sensations. These have included subjective reports based on self-evaluations and/or clinical observations describing motor, as well as sensory-based corporeal anomalies. There has been, however, a paucity of objective methods to capture and characterize bodily issues in SZ. Here we present a new research method and statistical platform that enables precise evaluation of peripheral activity and its putative contributions to the cognitive control of visuomotor actions. Specifically, we introduce new methods that facilitate the individualized characterization of the function of sensory-motor systems so as to detect if subjects perform outside of normal limits. In this paper, we report data from a cohort of patients with a clinical diagnosis of SZ. First, we characterize neurotypical subjects performing a visually guided pointing task that requires visuomotor transformations, multi-joint coordination, and the proper balance between different degrees of intent, among other factors. Then we measure SZ patients against the normative statistical ranges empirically determined. To this end, we examine the stochastic signatures of minute fluctuations in motor performance (micro-movements) of various velocity- and geometric-transformation-dependent trajectory parameters from the hand motions. These include the motions en-route to the target as well as spontaneous (without instructions) hand-retractions to rest. The comparisons reveal fundamental differences between SZ patients and controls. Specifically, velocity-dependent signatures show that SZ patients move significantly slower than controls with more noise and randomness in their moment-by-moment hand micro-motions. Furthermore, the normative geometric-dependent signatures of deliberateness are absent from the goal-directed reaches in SZ, but present within normative ranges in their spontaneous hand retractions to rest. Given that the continuous flow of micro-motions contributes to internally sensed feedback from self-produced movements, it is highly probable that sensory-motor integration with externally perceived inputs is impaired. Such impairments in this SZ cohort seem to specifically alter the balance between deliberate and spontaneous control of actions. We interpret these results as potential indexes of avolition and lack of agency and action ownership. We frame our results in the broad context of Precision Psychiatry initiatives and discuss possible implications on the putative contributions of the peripheral nervous system to the internal models for the cognitive control of self-produced actions in the individual with a clinical diagnosis of SZ., (Copyright © 2016 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Rationale: Individuals with Parkinson's disease (PD) often have deficits in kinesthesia. There is a need for rehabilitation interventions that improve these kinesthetic deficits. Forced (tandem) cycling at a high cadence improves motor function. However, tandem cycling is difficult to implement in a rehabilitation setting. Objective: To construct an instrumented, motored cycle and to examine if high cadence dynamic cycling promotes improvements in motor function. Method: This motored cycle had two different modes: dynamic and static cycling. In dynamic mode, the motor maintained 75-85 rpm. In static mode, the rider determined the pedaling cadence. UPDRS Motor III and Timed Up and Go (TUG) were used to assess changes in motor function after three cycling sessions. Results: Individuals in the static group showed a lower cadence but a higher power, torque and heart rate than the dynamic group. UPDRS score showed a significant 13.9% improvement in the dynamic group and only a 0.9% improvement in the static group. There was also a 16.5% improvement in TUG time in the dynamic group but only an 8% improvement in the static group. Conclusion: These findings show that dynamic cycling can improve PD motor function and that activation of proprioceptors with a high cadence but variable pattern may be important for motor improvements in PD. [ABSTRACT FROM AUTHOR]

SK is an 84-year-old woman diagnosed with essential tremor (ET) but no cognitive deficits. In this experiment, we tested the effects of mental rotation (a form of additional cognitive load) during reaching behavior (with the right hand) on the tremor profile of the non-moving left hand. We observed a marked increase in tremor and its variability, as well as the “freezing” of the movement pattern as effects of the cognitive load. These findings imply cognitive–motor overlaps in patients with ET, raising the possibility that the deficits reflect the loss of a common pool of neural resources, despite the heterogeneity of the symptoms of the disorder. [ABSTRACT FROM AUTHOR]

Background: Complex movement sequences are composed of segments with different levels of functionality: intended segments towards a goal and segments that spontaneously occur largely beneath our awareness. It is not known if these spontaneously-occurring segments could be informative of the learning progression in naïve subjects trying to skillfully master a new sport routine. Methods: To address this question we asked if the hand speed variability could be modeled as a stochastic process where each trial speed depended on the speed of the previous trial. We specifically asked if the hand speed maximum from a previous trial could accurately predict the maximum speed of a sub-sequent trial in both intended and spontaneous movement segments. We further asked whether experts and novices manifested similar models, despite different kinematic dynamics and assessed the predictive power of the spontaneous fluctuations in the incidental motions. Results: We found a simple power rule to parameterize speed variability for expert and novices with accurate predictive value despite randomly instructed speed levels and training contexts. This rule on average tended to yield similar exponent across speed levels for intended motion segments. Yet for the spontaneous segments the speed fluctuations had exponents that changed as a function of speed level and training context. Two conditions highlighted the expert performance: broad bandwidth of velocity-dependent parameter values and low noise-to- signal ratios that unambiguously distinguished between training regimes. Neither of these was yet manifested in the novices. Conclusions: We suggest that the statistics of intended motions may be a predictor of overall expertise level, whereas those of spontaneously occurring incidental motions may serve to track learning progression in different training contexts. These spontaneous fluctuations may help the central systems to kinesthetically discriminate the peripheral re-afferent patterns of movement variability associated with changes in movement speed and training context. We further propose that during learning the acquisition of both broad bandwidth of speeds and low noise-to-signal ratios may be critical to build a verifiable kinesthetic (movement) percept and reach the type of automaticity that an expert acquires. [ABSTRACT FROM AUTHOR]

The article focuses on peripheral noise in patients suffering from autism spectrum disorders. It is stated that on the basis of sensorimotor findings, it can be said that various kinds of peripheral noise lead to unpredictability of the person's movements. It is mentioned that people with autism show goal-directness, but their re-afferent feedback is unable to establish probabilistic expectations of their own movement variations.