Impaired Sensorimotor Adaption in Schizophrenia in Comparison to Age-Matched and Elderly Controls

Abstract

<b><i>Background:</i></b> The “cognitive dysmetria hypothesis” of schizophrenia proposes a disrupted communication between the cerebellum and cerebral cortex, resulting in sensorimotor and cognitive symptoms. Sensorimotor adaptation relies strongly on the function of the cerebellum. <b><i>Objectives:</i></b> This study investigated whether sensorimotor adaptation is reduced in schizophrenia compared with age-matched and elderly healthy controls. <b><i>Methods:</i></b> Twenty-nine stably treated patients with schizophrenia, 30 age-matched, and 30 elderly controls were tested in three motor adaptation tasks in which visual movement feedback was unexpectedly altered. In the “rotation adaptation task” the perturbation consisted of a rotation (30° clockwise), in the “gain adaptation task” the extent of the movement feedback was reduced (by a factor of 0.7) and in the “vertical reversal task,” up- and downward pen movements were reversed by 180°. <b><i>Results:</i></b> Patients with schizophrenia adapted to the perturbations, but their movement times and errors were substantially larger than controls. Unexpectedly, the magnitude of adaptation was significantly smaller in schizophrenia than elderly participants. The impairment already occurred during the first adaptation trials, pointing to a decline in explicit strategy use. Additionally, post-adaptation aftereffects provided strong evidence for impaired implicit adaptation learning. Both negative and positive schizophrenia symptom severities were correlated with indices of the amount of adaptation and its aftereffects. <b><i>Conclusions:</i></b> Both explicit and implicit components of sensorimotor adaptation learning were reduced in patients with schizophrenia, adding to the evidence for a role of the cerebellum in the pathophysiology of schizophrenia. Elderly individuals outperformed schizophrenia patients in the adaptation learning tasks.

Motor learning and performance in schizophrenia and aging: two different patterns of decline

“…Furthermore, older adults rely more on visual control. This could explain why in this study elderly individuals were hardly effected by an unexpectedly altered (rotated or shortened) visual feedback of their movements on adaptation tasks (Cornelis et al 2022 ). Online correction, driven by visual feedback, has become part of their normal habit.…”

“…Adaptation tasks were administered using the Rotation Adaptation Task (AdapR) and the Gain Adaptation Task (AdapG) (Cornelis et al 2022 ). Participants had to make fast pen/hand upward movements towards a target as quickly as possible, but the visual movement feedback was unexpectedly altered (rotated or shortened).…”

“…Baseline trials with normal feedback were compared with adaptation trials and post-adaptation trials. The Vertical Reversal Task (VRT) (Cornelis et al 2022 ) measured more explicit adaptation as participants were fully informed about the change in visual feedback, namely that feedback on vertical movements was reversed 180°. This required a kind of mirror drawing.…”

Facilitation of sensorimotor temporal recalibration mechanisms by cerebellar tDCS in patients with schizophrenia spectrum disorder and healthy subjects

“…Among them is the process of sensorimotor adaptation, i.e., the adaptation of movements in response to a discrepancy between predicted and observed sensory outcomes of these movements. [54][55][56] For instance, compared to healthy subjects, patients exhibited impaired sensorimotor adaptation abilities in tasks where movements had to adapt to shifted or rotated visual feedback, [57][58][59] and reduced saccade adaptation. 60,61 These adaptation deficits in SSD may also be explained by dysfunctions in accurately building and updating internal forward models in the cerebellum to minimize the error between predicted and perceived sensory actionoutcomes.…”

“…60,61 These adaptation deficits in SSD may also be explained by dysfunctions in accurately building and updating internal forward models in the cerebellum to minimize the error between predicted and perceived sensory actionoutcomes. 59,61 In healthy subjects, tDCS on the cerebellum already showed the potential to improve sensorimotor adaptation performances in similar tasks. [62][63][64] Initial evidence in non-clinical psychosis further demonstrated the effectiveness of cerebellar tDCS in ameliorating sensorimotor learning deficits.…”