What can speech tell us about pain?

Introduction: Pain experiences are subjective and can vary significantly between individuals, yet pain is universally communicated using speech. Analysis of speech itself may be clinically informative about pain. Speaking itself may also relieve pain as it does during basic vocalisations. Whether complex speech relieves pain is not known. Understanding speech when pain is being experienced and whether certain speech features are associated with general pain sensitivity holds promise for identifying pain markers. Objectives: We investigated the (1) effect of acute pain on speech characteristics, (2) effect of speech on pain intensity, and (3) association between pain-free speech characteristics and pain sensitivity. Methods: Speech metrics were derived from 25 healthy adults who performed speech tasks that fit along a continuum of cognitive complexity, with and without acute exposure to noxious heat stimuli. Pain ratings were also recorded. Results: Speech was pain-sensitive: under acute pain syllabic rate and speech-to-pause ratio increased during a monologue task, while mean sound pressure level decreased during vowel production. Exploratory correlations between pain-free speech characteristics and baseline pain sensitivity were significant. Increased speech-to-pause ratio was associated with increased cold pain sensitivity, while decreased mean sound pressure level was related to higher pressure pain sensitivity and impaired conditioned pain modulation. Producing a monologue reduced pain more than saying /a:/. Conclusion: Speech can serve as a marker of acute pain. It also correlates with pain sensitivity, suggesting that speech could be useful for pain assessment and management.