Objective:

To evaluate mental rotation performance in various dystonia subtypes and explore the proposed mechanisms underlying their pathophysiologies.

Background:

Dystonia is a movement disorder characterized by involuntary muscle contractions, leading to repetitive motions and abnormal postures. The mental rotation task (MRT) is a cognitive paradigm that studies the process of manipulating visual objects in space and is a marker of visuospatial dysfunction. MRT engages cortical and subcortical areas involved in motor planning and execution, including parietal association, cerebellar, and motor cortices.

Design/Methods:

A literature review was conducted on behavioral studies comparing patients with cervical dystonia (CD), focal hand dystonia (writers’ cramp, musicians’ dystonia), fixed and mobile dystonia, or DYT1 mutation carriers to healthy controls. Participants completed spatial mental rotation tasks with letters, corporeal (hand, feet, full body) or non-corporeal objects (cars) stimuli in various orientations. 207 dystonia patients and 154 healthy participants were included in total. Reaction times and accuracy rates were measured.

Results:

CD patients exhibited slower reaction times in mental rotation of body-part stimuli compared to controls, particularly with back-facing bodies, while performance with non-corporeal objects remained intact. Writer's cramp patients displayed hand-specific deficits, whereas musicians’ dystonia showed similar mental rotation abilities as controls, indicating task-specific deficits. Fixed and mobile dystonia patients displayed longer reaction times in body part rotation compared to controls, suggesting shared disturbances in body schema. DYT1 mutation carriers showed slower times for rotation of body parts but not objects, reflecting a potential endophenotypic feature in movement representation.

Conclusions:

MRT reveals that dystonia is not purely a motor disorder, but involves non-motor components that influence sensorimotor integration, temporal prediction, and cognitive processing of movement. Although mental rotation deficits are observed across many forms of dystonia, the underlying mechanisms are complex and may demonstrate distinct neural circuitries. Despite limited data, MRT holds potential as a valuable tool for distinguishing dystonia phenotypes.