A new approach to the construct of alertness

Area of Science:

• Psychometric validation
• Sleep science
• Clinical psychology

Background:

• Currently, no validated psychometric measures exist to assess the crucial construct of alertness.
• Developing reliable tools to quantify alertness is essential for understanding and managing sleep-related disorders.

Purpose of the Study:

• To develop and psychometrically evaluate two novel questionnaires, the Toronto Hospital Alertness Test (THAT) and the ZOGIM-A, for measuring subjective alertness.
• To assess the reliability and validity of these instruments in a sleep clinic outpatient population.

Main Methods:

• The study involved 96 sleep clinic outpatients, assessing the correlation between THAT and ZOGIM-A scores with objective measures like the Maintenance of Wakefulness Test (MWT) and physiological sleep parameters.
• Test-retest reliability was evaluated using an independent sample of 295 outpatients.
• Psychosocial variables, including psychological well-being and emotional distress, were also assessed.

Main Results:

• Both the THAT (r(tt)=.79) and ZOGIM-A (r(tt)=.70) demonstrated high test-retest reliability.
• Excellent internal consistency was found for THAT (.96) and ZOGIM-A (.83).
• While not correlating with objective MWT or physiological sleep measures, the scales showed significant correlations with subjective sleepiness and psychosocial variables as hypothesized.

Conclusions:

• The findings support the view that subjective alertness is a distinct construct, not merely the absence of sleepiness.
• The THAT and ZOGIM-A are psychometrically sound instruments that provide unique measures of alertness.
• These questionnaires complement objective data from MWT and sleep physiology, offering a more comprehensive assessment of alertness.