Self-reported sleepiness in the context of fitness-to-drive

Excessive daytime sleepiness (EDS) is a contributing factor to road traffic accidents. It is commonly assessed using self-administered questionnaires. These assessments are important information when discussing with the Driver and Vehicle Licensing Agency (DVLA) about fitness-to-drive. We hypothesised that patients may be confounded in their assessments after being informed about these potential implications.

This was a prospective single-centre study. Patients attending clinics for sleep-disordered breathing were asked to fill in the Epworth Sleepiness Scale (ESS) and the Stanford Sleepiness Scale (SSS). Following their consultation, patients were informed about EDS in the context of driving and that the DVLA might request information based on their self-assessed sleepiness. They were then asked to complete the same questionnaires again. Parameters recorded included age, gender, body mass index (BMI), driving licence holder, and collar size. An ESS score above 10 points was defined as EDS.

One hundred twenty-two subjects were studied (age 59.4 years (15.2); 72 males; BMI 32.1 kg/m² (8.3), driving licence held for 25.2 years (20.6) (n = 94); collar size 42.7 cm (5.0)). There was no difference in the ESS [8 (8) vs 8 (8) points; p = 0.289] or the SSS [2 (2) vs 2 (2) points; p = 0.320] between the two occasions, although seven patients (5.7%) changed their scores from "sleepy" to "non-sleepy" and four patients (3.3%) from "non-sleepy" to "sleepy".

Providing patients with information about the risk of driving in the context of sleepiness does not significantly change how they score their symptoms using self-administered questionnaires; only about 9.0% of the patients had inconsistent results.