Speech deficits in serious mental illness: a cognitive resource issue?

Area of Science:

• Psycholinguistics
• Neuroscience
• Clinical Psychology

Background:

• Serious mental illnesses (SMI) like schizophrenia and bipolar disorder often present with speech deficits.
• These deficits include psychomotor retardation, blunted affect, alogia, and poverty of content of speech.
• The relationship between these speech impairments and cognitive resource limitations remains an area of investigation.

Purpose of the Study:

• To investigate the extent to which speech deficits in SMI manifest as a function of cognitive resource limitations.
• To compare speech production, variability, and content between patients with SMI and healthy controls under varying cognitive loads.
• To explore correlations between speech variables and cognitive abilities in individuals with and without SMI.

Main Methods:

• Examined natural speech from 52 patients with SMI and 30 controls using objective, computer-based measures.
• Assessed speech production (alogia), variability (blunted vocal affect), and content (poverty of content of speech).
• Speech was analyzed during baseline and a cognitively-effortful task; cognitive ability was measured using a standardized battery.

Main Results:

• Speech deficits in production and content were significantly more prevalent in the SMI group compared to controls.
• Both patients and controls exhibited sparser and less content-rich speech during the cognitively-effortful task.
• Patients with SMI showed abnormalities in average pause length under cognitive load, correlating with cognitive ability.

Conclusions:

• Speech deficits, particularly in pause length, may be linked to cognitive resource limitations in serious mental illness.
• Findings suggest that cognitive load exacerbates speech impairments in individuals with SMI.
• Results have implications for the assessment and treatment of speech disturbances in psychiatric populations.