Pointing in cervical dystonia patients

Maria Paola Tramonti Fantozzi; Roberta Benedetti; Alessandra Crecchi; Lucia Briscese; Paolo Andre; Pieranna Arrighi; Luca Bonfiglio; Maria Chiara Carboncini; Luca Bruschini; Paolo Bongioanni; Ugo Faraguna; Diego Manzoni

doi:10.3389/fnsys.2023.1306387

Pointing in cervical dystonia patients

Front Syst Neurosci. 2023 Nov 28:17:1306387. doi: 10.3389/fnsys.2023.1306387. eCollection 2023.

Authors

Maria Paola Tramonti Fantozzi¹, Roberta Benedetti^{1

2}, Alessandra Crecchi³, Lucia Briscese³, Paolo Andre⁴, Pieranna Arrighi^#⁵, Luca Bonfiglio^{1

6}, Maria Chiara Carboncini^#¹, Luca Bruschini⁷, Paolo Bongioanni^#⁵, Ugo Faraguna^#^{1

8}, Diego Manzoni^#¹

Affiliations

¹ Department of Translational Research and of New Surgical and Medical Technologies, University of Pisa, Pisa, Italy.
² Residency School in Physical Medicine and Rehabilitation, University of Pisa, Pisa, Italy.
³ Functional Rehabilitation Unit, North-West Tuscany Sanitary Service, Pisa, Italy.
⁴ Department of Medicine, Surgery and Neuroscience, University of Siena, Siena, Italy.
⁵ Severe Acquired Brain Injuries Section, Integrated Department of Medical Specialties, Pisa University Hospital, Pisa, Italy.
⁶ Developmental Neurorehabilitation Section, Maternal and Child Department, Pisa University Hospital, Pisa, Italy.
⁷ Department of Surgical, Medical, Molecular Pathology and Critical Cares, University of Pisa, Pisa, Italy.
⁸ Department of Developmental Neuroscience, IRCCS Fondazione Stella Maris, Pisa, Italy.

^# Contributed equally.

Abstract

Introduction: The normal hemispheric balance can be altered by the asymmetric sensorimotor signal elicited by Cervical Dystonia (CD), leading to motor and cognitive deficits.

Methods: Directional errors, peak velocities, movement and reaction times of pointing towards out-of-reach targets in the horizontal plane were analysed in 18 CD patients and in 11 aged-matched healthy controls.

Results: CD patients displayed a larger scatter of individual trials around the average pointing direction (variable error) than normal subjects, whatever the arm used, and the target pointed. When pointing in the left hemispace, all subjects showed a left deviation (constant error) with respect to the target position, which was significantly larger in CD patients than controls, whatever the direction of the abnormal neck torsion could be. Reaction times were larger and peak velocities lower in CD patients than controls.

Discussion: Deficits in the pointing precision of CD patients may arise from a disruption of motor commands related to the sensorimotor imbalance, from a subtle increase in shoulder rigidity or from a reduced agonists activation. Their larger left bias in pointing to left targets could be due to an increased right parietal dominance, independently upon the direction of head roll/jaw rotation which expands the left space representation and/or increases left spatial attention. These deficits may potentially extend to tracking and gazing objects in the left hemispace, leading to reduced skills in spatial-dependent motor and cognitive performance.

Keywords: asymmetry; cervical dystonia; neck input; pointing errors; space representation.

Grants and funding

The author(s) declare financial support was received for the research, authorship, and/or publication of this article. This work was supported by a grant of the Pisa University to LB (Ninth author). The funder had no role in the study design, data collection and analysis, decision to publish and preparation of the manuscript.