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S25 Establishing a normal range in driving simulator performance using standard deviation of lane position (SDLP) in an advanced PC –based driving simulator (MiniUoLDS)
  1. A Dwarakanath1,
  2. D Ghosh1,
  3. SL Baxter2,
  4. PD Baxter3,
  5. MW Elliott1
  1. 1St. James’ University Hospital, Leeds, UK
  2. 2Institute for Transport Studies, University of Leeds, Leeds, UK
  3. 3LIGHT, Centre for Epidemiology and Biostatistics, University of Leeds, Leeds, UK


Introduction Some patients with OSAS are at higher risk of being involved in road traffic accidents. No objective tests have been shown to predict reliably whether an individual is safe to drive or not and there is significant variation in the advice given by the clinicians. Using a continuously measured variable (SDLP) on an advanced PC-based driving simulator the at risk patients can be identified with a high degree of accuracy. We have now compared driving performance based on SDLP in controls and untreated OSAS patients and have established a normal range.

Methods 129 untreated male OSAS patients (Age 53+/-12, ESS 14+/-5, ODI 41+/-26, BMI 36+/-8,) and 79 male controls (Age 56+/-15, ESS 4+/-3, BMI 28+/-8) were recruited in the study. All performed a simulator run after initial acclimatisation. The simulator run consisted of eight epochs and on average needed 7 min to complete one epoch driving at 70 miles per hour. The simulator layout was designed in line with the UK highways agency road standards. The mean SDLP in epoch-3 (SDLP3) was compared between the two groups using unpaired T-test. The SDLP3 in the patient group was evaluated and this was compared with the mean and 95th centile values of SDLP 3 among the controls.

Results There was a significant difference in SDLP3 between OSAS patients and controls (0.44 v/s 0.39, P = 0.03). 10% of patients had worse SDLP3 than the 95th centile among controls (Figure 1).

Conclusions Worse SDLP is a marker of poor driving performance and this is significantly worse in untreated OSAS patients as compared to controls. The choice of 95% is arbitrary but is consistent with the approach taken to establish a normal range. Establishing where a patient lies in comparison to controls may be useful in advising patients whether they are at increased risk of an accident due to OSAS. Defining a normal range based on continuously measured variable in MiniUoLDS holds promise and is a step ahead towards developing an objective test in evaluating the at risk OSAS patients.

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