Head movements during conversational speech in patients with schizophrenia.

BACKGROUND: Motor abnormalities are frequently described in schizophrenia, and work by Altorfer and colleagues suggests that measuring head movements during conversational speech shows differences at the level of the individual. We wished to see whether their findings, conducted using computer analysis of video obtained in motion capture suites, could be replicated using compact, portable movement sensors, in a case-control study comparing the mean amplitude of head movements during general conversation.
METHODS: A referred sample of inpatients and outpatients with a diagnosis of paranoid schizophrenia was identified from case note information. Movement sensors, mounted in a baseball cap worn by subjects, transmitted data via Bluetooth to a laptop, which simultaneously captured audio to identify who was speaking. Subjects also completed a series of rating scales.
RESULTS: Data from the final 11 cases and 11 controls demonstrated a substantial group difference in mean amplitude of head movement velocity during speech (p < 0.0001), although this was not significant at the level of the individual.
CONCLUSIONS: Movement sensors proved well suited to capturing head movements, demonstrating a large effect size in subjects with schizophrenia.