Factor analysis and clustering of motor and psychiatric dimensions in idiopathic blepharospasm

Angelo F Gigante; Mark Hallett; Hyder A Jinnah; Alfredo Berardelli; Joel S Perlmutter; Brian D Berman; Joseph Jankovic; Tobias Bäumer; Cynthia Comella; Tommaso Ercoli; Daniele Belvisi; Susan H Fox; Han-Joon Kim; Emile Sami Moukheiber; Sarah Pirio Richardson; Anne Weissbach; Antonella Muroni; Giovanni Defazio

doi:10.1016/j.parkreldis.2024.107241

Factor analysis and clustering of motor and psychiatric dimensions in idiopathic blepharospasm

Parkinsonism Relat Disord. 2024 Dec 16:131:107241. doi: 10.1016/j.parkreldis.2024.107241. Online ahead of print.

Authors

Angelo F Gigante¹, Mark Hallett², Hyder A Jinnah³, Alfredo Berardelli⁴, Joel S Perlmutter⁵, Brian D Berman⁶, Joseph Jankovic⁷, Tobias Bäumer⁸, Cynthia Comella⁹, Tommaso Ercoli¹⁰, Daniele Belvisi¹¹, Susan H Fox¹², Han-Joon Kim¹³, Emile Sami Moukheiber¹⁴, Sarah Pirio Richardson¹⁵, Anne Weissbach¹⁶, Antonella Muroni¹⁷, Giovanni Defazio¹⁸

Affiliations

¹ Section of Neurology, San Paolo Hospital, Bari, Italy.
² National Institute of Neurological Disorders and Stroke, NIH, Bethesda, USA.
³ Department of Neurology and Human Genetics, Emory University School of Medicine, Atlanta, GA, USA.
⁴ Department of Human Neurosciences, Sapienza University of Rome, Italy; IRCCS NEUROMED, Pozzilli, Italy.
⁵ Department of Neurology, Radiology, Neuroscience, Physical Therapy and Occupational Therapy, Washington University School of Medicine, St Louis, MO, USA.
⁶ Department of Neurology, Virginia Commonwealth University, Richmond, VA, USA.
⁷ Parkinson's Disease Center and Movement Disorders Clinic, Department of Neurology, Baylor College of Medicine, Houston, TX, USA.
⁸ Institute of Systems Motor Science, University of Lübeck, Germany.
⁹ Department of Neurological Sciences, Rush University Medical Center, Chicago, Illinois, USA.
¹⁰ Department of Medical Sciences and Public Health, University of Cagliari, Italy.
¹¹ Department of Human Neurosciences, Sapienza University of Rome, Italy.
¹² Movement Disorder Clinic, Krembil Brain Institute, University Health Network, Toronto, Ontario, Canada.
¹³ Department of Neurology and Movement Disorder Centre, Seoul National University Hospital, Seoul, South Korea.
¹⁴ Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD, USA.
¹⁵ Department of Neurology, University of New Mexico/New Mexico VA Healthcare System, Albuquerque, NM, USA.
¹⁶ Institute of Systems Motor Science and Institute of Neurogenetics, University of Lübeck, Germany.
¹⁷ Neurology Unit, Azienda Ospedaliero-Universitaria of Cagliari, Italy. Electronic address: [email protected].
¹⁸ IRCCS NEUROMED, Pozzilli, Italy; Department of Translational Biomedicine and Neuroscience, Aldo Moro University of Bari, Italy.

PMID: 39731886
DOI: 10.1016/j.parkreldis.2024.107241

Abstract

Introduction: Idiopathic blepharospasm is a clinically heterogeneous form of focal dystonia, also associated with psychiatric symptoms. The identification of the most relevant sets of motor and psychiatric manifestations may help better understand the specific phenomenology of the condition and delineate blepharospasm subtypes more accurately.

Methods: Patients with idiopathic blepharospasm were from the Dystonia Coalition project. Factor analysis of several motor and psychiatric scales was performed to identify the relevant determinants of blepharospasm severity. The selected items were then used in a data-driven cluster analysis to subtype blepharospasm individuals.

Results: Factor analysis reduced the many variables in the motor and psychiatric scales to 13 variables distributed in four factors. When the four sets were used as clustering variables, three blepharospasm clusters were identified: cluster 1 was characterized by low levels of motor and psychiatric factors; cluster 2 showed high levels of both motor and psychiatric factors; and cluster 3 showed high levels of psychiatric factors (similar to cluster 2) but low level of motor factors (similar to that of cluster 1).

Conclusions: Factor analysis enabled the identification of key motor and psychiatric determinants of blepharospasm severity. The derived factor sets provide a streamlined tool for predicting and measuring these dimensions. This approach also facilitated more precise cluster analysis and improved recognition of clinical subtypes.