Study Uncovers Brain Network Behind Psychomotor Disturbances in Psychiatric Disorders

A study published June 25 in the American Journal of Psychiatry provides new insights into a long-standing question in psychiatric research: What is the underlying neurobiological mechanism of psychomotor disturbance in psychiatric disorders? ^[1]

This study, which explores the relationship between brain connectivity and motor function, reveals a connection between grip strength, well-being and the brain’s default mode network (DMN), offering novel insights for potential clinical applications.

Psychomotor disturbances — ranging from catatonia and psychomotor agitation to disorganized behavior and repetitive movements — are highly prevalent in psychiatric conditions. Despite their high prevalence, the neural mechanisms behind these disturbances have remained elusive.

“There has been an exponential increase in the interest to understand psychomotor processes in disease pathology — the fundamental nature of the motor system enhances our ability to link psychological processes to brain to symptoms, promoting clinically useful targets for intervention,” said senior author Alexandra Moussa-Tooks, PhD, an adjunct professor at Vanderbilt University School of Medicine, and co-director of the Clinical and Cognitive Neuroscience Center and head of the Motor Adaptations in Psychotic Disorders Lab at Indiana University Bloomington.

One of the main focuses of this study is the role of grip strength as a measure of both motor function and overall well-being.

“Grip strength is one measure of motor function that has been associated with all-cause mortality and overall well-being,” said first author Heather Burrell Ward, MD, assistant professor of Psychiatry and Behavioral Sciences at Vanderbilt University Medical Center. “It has been assumed that associations between grip strength and well-being are purely related to mechanical impairments reflective of overall poorer physical health.

This study takes a groundbreaking approach by identifying brain regions beyond the motor system that contribute to grip strength and overall health. Using data from the multisite Human Connectome Project for Early Psychosis, which involved 206 participants, including individuals with early psychosis and healthy controls, the researchers applied a data-driven, connectome-wide analysis to uncover the brain circuits associated with grip strength and well-being.

Given the associations between grip strength and well-being, researchers then repeated this analysis to determine if they would identify similar brain correlates for grip strength and well-being — and they did.

“We identified significant relationships between the same brain regions and their connectivity patterns to the DMN that were related to well-being, overall function and grip strength,” Ward said. “These results have dramatic implications for treatment of psychomotor function in psychotic disorders, as they suggest a unifying role of DMN connectivity in psychomotor disturbance, overall function and well-being.”

Specifically, interventions targeting DMN connectivity could be used to treat psychomotor disturbance and well-being. Repetitive transcranial magnetic stimulation (rTMS) is one form of noninvasive brain stimulation that can be used to modulate DMN connectivity. As director of Neuromodulation Research in the Department of Psychiatry, Ward is currently leading multiple clinical trials that use rTMS to modulate DMN connectivity for people with psychosis.

Reference:

1. Grip Strength as a Marker of Resting-State Network Integrity and Well-Being in Early Psychosis - https://psychiatryonline.org/doi/10.1176/appi.ajp.20240780

(Newswise/SH)