The ease-of-use and standardization of a tablet-based approach to quantify parkinsonian bradykinesia can aid in diagnosing bradykinesia in patients with schizophrenia treated with antipsychotics, a recent study found. Researchers applied prior findings on the pathophysiology of bradykinesia in Parkinson disease PD to gain an understanding of motor slowing in patients with psychosis. Handwriting movements from 57 healthy participants and 70 patients with psychosis were recorded on a digitizing tablet. Temporal and kinematic features were extracted from handwritten loops and circles. An independent objective measure, based on peak velocity for circles written at maximum speed, was used to classify patients as bradykinetic. They found:
- Bradykinetic patients produced handwriting movements with longer stroke durations, smaller amplitudes, and lower peak velocities compared with non-bradykinetic patients.
- 36% of the pen strokes produced by the bradykinetic patients were non-ballistic compared with 20% for the non-bradykinetic patients.
- The proportion of non-ballistic movements observed in handwriting was unrelated to current antipsychotic dose, severity of negative psychosis, or depression.
Caligiuri MP, Teulings H-L, Dean CE, Lohr JB. The nature of bradykinesia in schizophrenia treated with antipsychotics. Psychiatry Res. 2019;273:537-543. doi:10.1016/j.psychres.2019.01.058.
Antipsychotic drug-induced extrapyramidal side effects (EPS) can cause a host of unwanted consequences, including functional impairment and complications, such as falls or accidents. However, assessing EPS is often challenging as it traditionally relies upon physical examination done by clinicians who may have different assessment approaches and variable and/or biased interpretations of observed motor abnormalities. Drug-induced parkinsonian bradykinesia in patients with schizophrenia can be particularly challenging to assess as it may resemble the motor slowing seen in depression, cognitive impairment, or even the negative symptoms seen in many patients with schizophrenia. This report compared handwriting analysis using standardized and technology-facilitated methods to assess bradykinesia vs a standard clinical evaluation. While findings are very preliminary, handwriting analysis is an intriguing and potentially novel approach to quantifying a common and frequently disabling problem associated with antipsychotic drug treatment.—Martha Sajatovic, MD, Professor of Psychiatry and of Neurology; Willard Brown Chair in Neurological Outcomes Research; Director, Neurological and Behavioral Outcomes Center, University Hospitals Cleveland Medical Center; Case Western Reserve University School of Medicine.