Alertness

Fatigue and reduced alertness impact speech motor control and cognitive-linguistic function, which can be objectively measured through speech. Redenlab enables passive and task-based assessments of fatigue-related changes, supporting drug safety, CNS trials, and occupational health monitoring.

Speech and language biometrics in alertness

Fatigue and sleepiness are common across neurological, psychiatric, and systemic conditions, yet remain difficult to quantify beyond subjective self-report. These states directly affect speech production, altering timing, prosody, articulation, and verbal fluency,often before overt behavioural signs emerge. These changes can impair safety, cognition, and quality of life, especially in high-risk settings such as shift work, driving, and clinical trials of CNS-active compounds. Redenlab’s speech-based assessments offer a non-invasive, real-time window into alertness, providing sensitive endpoints for fatigue monitoring, sleep research, and pharmacodynamic profiling.

Redenlab speech analytics for fatigue & sleepiness

Sensitive to diurnal and pharmacological changes

Detects fatigue-related slowing, hesitation, and voice quality shifts tied to time of day or compound effects.

Validated in sleep restriction and sedative studies

Speech changes correlate with psychomotor vigilance and subjective alertness under experimental sleep loss and drug-induced drowsiness.

Low-burden, high-frequency sampling

Speech tasks can be administered in seconds, allowing repeated measures across long protocols or real-world settings.

Supports CNS drug safety

Applied in trials evaluating sedative load, alertness, and central nervous system tolerability.

Applicable to clinical and occupational contexts

Useful in populations with chronic fatigue, sleep disorders, neurodegeneration, and safety-critical professions.

Redenlab’s experience in alertness, fatigue & sleepiness research

Redenlab has conducted a series of controlled laboratory and field-based studies examining how fatigue and reduced alertness influence speech production. Across four key investigations:

• 24-hour and 40-hour sustained wakefulness protocols in healthy adults demonstrated progressive changes in speech timing, fluency, and voice quality, closely mirroring cognitive decline measured by tools like the Cogstate reaction time test.
• In consecutive night shift studies with healthcare workers, Redenlab captured circadian- and shift-related variations in speech patterns, revealing degradation in speech rate and voice quality as Karolinska Sleepiness Scale (KSS) scores rose, even when psychomotor vigilance tests (PVT) failed to detect change.
• In a four-way double-blind, placebo-controlled crossover trial, participants received temazepam, zolpidem, or placebo and were assessed post-awakening from REM or slow-wave sleep. Speech measures sensitively reflected sedative impact and sleep-stage interactions.

These studies underscore Redenlab’s ability to detect real-time changes in alertness using brief speech tasks, outperforming traditional reaction-time tests in ecological sensitivity. This work informs our platform’s deployment in CNS-active compound trials, fatigue monitoring, and occupational risk assessment.