Obstructive sleep apnoea and daytime driver sleepiness

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CRICOS No. 00213J

Obstructive sleep apnoea and daytime driver sleepiness

Dr Ashleigh Filtness

(2)

Obstructive Sleep Apnoea (OSA)

 Repeated collapse of the airway during sleep blocking air flow.

 At least 5 an hour, some up to 60 an hour

 Most common in



Middle aged men



Collar >43cm



BMI ≥28



Symptoms



Daytime sleepiness (feeling un-rested after sleep)



Loud snoring



Holding breath during sleep



Gasping for air

(3)

Treatment

(4)

OSA and Driving

UK law

Group 1 licence holders (car/motorcycle) diagnosed with sleep apnoea must stop driving until the

symptoms have been controlled and confirmed by

medical opinion.

(5)

Research Evidence supports OSA return to driving

• Post-treatment, the incidence of road traffic collisions for this group is substantially

reduced. (Yamamoto et al. 2000; George 2001; Tregear et al. 2010;)

• Post-treatment performance at driving

simulator tasks improve. (Orth et al. 2005; Mazza et al.

2006)

– However, not in all studies (Vakulin et al. 2011)

(6)

Aim

To investigate the impact of modest sleep restriction and treatment withdrawal on driving ability in long term treated OSA.

1. Sleep restriction (5h) with CPAP treatment 2. Normal length of sleep (≈7h) without CPAP

treatment

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(7)

Vulnerability to sleep restriction

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Participants

39 participants male (19 with OSA), age 50 – 75y

OSA Control

Age 63.8 (1.7) 66.6 (1.3)

BMI 34.5 (1.4) 25.5 (0.4)

ESS 5.3 (0.7) 4.7 (0.6)

Usual sleep 7h 40min (8.1 min) 7h 48 min (10.1 min) Treatment

duration

≥1y

Average 7.5y (5.7)

NA

(9)

Methodology - Driving Simulator

30 min practice drive Repeated measure

counterbalanced design

• Normal nights sleep (8 h)

• Sleep restriction to (5 h)

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(10)

Simulated road

Monotonous dual carriageway 2 h duration starting at 2pm Occasional slow moving

vehicles to overtake

(11)

Measures

Prior sleep was verified using

actigraphy

(12)

Measures

• Driving incidents: all four wheels out of the driving lane.

• Subjective sleepiness:

Karolinska Sleepiness Scale (KSS) every 200 seconds.

• EEG: Spectral analysis in the

alpha and theta, 4 – 11Hz

range, and beta, 13 – 30 Hz

range

(13)

Results – Driving incidents

Significant group by condition interaction F(1,37) = 9.4, p < 0.05 Significant main effect of condition F(1,37) = 20.8, p < 0.001 Significant main effect of time on task F(1.7,63) = 15.0, p < 0.001

(14)

Results - Time to first driving incident

Significant group by condition interaction F(1,37) = 4.2, p < 0.05 Significant main effect of condition F(1,37) = 4.0, p < 0.05

(15)

Results - KSS

Significant main effect of condition F(1,37) = 19.9, p < 0.001

Significant main effect of driving time F(1.9,72.1) = 70.0, p < 0.001

(16)

Results – EEG alpha and theta

Significant group by time interaction F(1.7, 64.2) = 4.27, p < 0.05 Significant main effect of time F(1.7, 64.2) = 35.0, p < 0.001

(17)

Results EEG - beta

Significant group by time interaction F (1.8,65.6) = 4.9, p < 0.05 t(37) = 2.0, p < 0.05

(18)

Discussion – Sleep restriction

• No significant difference between driving performance after a normal nights sleep.

• Treated OSA patients show greater vulnerability to sleep restriction

– More incidents

– Shorter safe driving time.

(19)

Discussion – Sleep Restriction

• Despite performance decrements no significant

difference in subjective sleepiness groups when sleep deprived.

• Time on task following sleep restriction affected EEG activity differently for OSA compared with control participants particularly during second half of drive

– Alpha and theta

– Beta activity

(20)

Vulnerability to CPAP withdrawal

(21)

Participants

11 male participants with OSA age 50 – 75y

OSA

Age 65.6 (2.3)

BMI 33.1 (1.8)

ESS 5.2 (0.7)

Usual sleep 7h 45min (3.6 min) Treatment duration ≥1y

Average 7.7y (5.8)

(22)

Methodology - Driving Simulator

30 min practice drive

Repeated measure design

Normal nights sleep (with CPAP)

Normal nights sleep (no CPAP)

Monotonous dual carriageway 2 h duration starting at 2pm

Occasional slow moving vehicles to overtake

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(23)

Measures

Prior sleep was verified using actigraphy

• Driving incidents: all four wheels out of the driving lane.

• Subjective sleepiness: Karolinska Sleepiness Scale (KSS) every 200 seconds.

• EEG: Spectral analysis in the alpha

and theta, 4 – 11Hz range, and

beta, 13 – 30 Hz range

(24)

Sleep quality

SDI = number of wake minutes / assumed length of sleep Significant difference in SDI [t (10) = 3.510, p <0.05]

(25)

Results –Driving incidents

Significant group main effect of treatment withdrawal F(1,20) = 12.33, p < 0.05

(26)

Results - Time to first driving incident

Significant reduction in time to first incident t(10) = 3.8, p < 0.05

(27)

Safe driving time

(28)

Results - KSS

Significant main effect of condition F(1,10) = 24.12, p < 0.05

Significant drive time by condition interaction F(3,30) = 5.03, p < 0.05

(29)

Results – KSS and EEG (alpha and theta)

(30)

Results – KSS and EEG (alpha and theta

Significant correlation between KSS and EEG R2 = 0.77, p < 0.05

(31)

Discussion – CPAP withdrawal

• Increase in SDI although total sleep time remains similar

• CPAP withdrawal for one night impairs driving performance

– Overall number of incidents

– Time to first incident

(32)

Discussion – CPAP withdrawal

• Increased subjective sleepiness

– Aware of the withdrawal

• Although performance is impaired, insight into

sleepiness is apparent.

(33)

Conclusions

• CPAP treated OSA patients are more susceptible to the effects of sleep restriction

– Why?

• Missing only 1 night of treatment could be critical

• Patient education

• Control group were also affected

(34)

Publications

• Filtness, A.J., Reyner, L.A., Horne, J.A. (2011) Moderate sleep restriction in treated older male OSA participants: greater impairment during monotonous driving compared with controls. Sleep Medicine 12 (9) 838-843

• Filtness, A. J., Reyner, L. A., & Horne, J. A. (2012). One night’s CPAP withdrawal in otherwise compliant OSA patients:

marked driving impairment but good awareness of increased sleepiness. Sleep and Breathing 16(3) 865-871

• Filtness, A. J., Reyner, L. A., & Horne, J. A. (2012). Driver

sleepiness - comparisons between young and older men

during a monotonous afternoon simulated drive. Biological

Psychology 89 (3) 580 – 583

(35)

Acknowledgements

Dr Louise Reyner and Prof. Jim Horne,

Loughborough University

Dr Andrew Hall and Dr Chris Hanning,

Leicester General Hospital

(36)

Dr Paul Salmon Dr Mike Lenné

Dr Missy Rudin-Brown

(37)
(38)

Origins of CARRS-Q

 Centre for Accident Research & Road Safety –

Queensland (CARRS-Q) was established in 1996 as joint initiative of:

– QUT

– Motor Accident Insurance Commission (MAIC)

 Based in the School of Psychology & Counselling, Faculty of Health

 Primary role is to undertake research and training to improve safety on Queensland roads and in the

workplace

(39)

Research Themes

CARRS-Q currently has approximately 90 staff and students researching 6 themes:

 Regulation and Enforcement

 School and Community Injury Prevention

 Vulnerable Road Users

 Occupational Safety

 Road Safety Infrastructure

 Intelligent Transport Systems

(40)

School and Community Injury Prevention

Issues addressed:

 School-based education programs

 Community-based education programs

 Non-enforceable high-risk behaviours e.g. fatigue

Research projects include:

• Understanding sleep in carers (dementia and older adults)

• Postpartum fatigue: Effects on safety-sensitive tasks

• Motivations to drive when sleepy

• Proxy definitions of sleep related crashes

(41)

Regulation and Enforcement

Issues addressed:

 Drink Driving

 Drug Driving

 Speeding

 Aggressive Driving

 Unlicensed Driving

Research projects include:

 Development of a brief computer based intervention for first time drink driving offenders

 Design and evaluation of anti-speeding messages to target high risk road users' attitudes and behaviours

 The road safety implications of unlicensed driving

(42)

Vulnerable Road Users

Issued addressed:

 Motorcycle riders

 Pedestrians

 Cyclists

Research projects include:

 Development and evaluation of a motorcycle training intervention

 Compendium of best practices on motorcycle and scooter safety

 Delineating injury patterns and safety behaviours among

cyclist groups

(43)

Occupational Safety

Issues addressed:

 Work-related driver safety

 Fleet safety

 Workplace Health and Safety Policy Previous research projects include:

 Safety in the heavy vehicle industry

 Development and evaluation of an OH&S framework for work related driving

 Developing driving risk assessment tools to improve fleet

safety

(44)

Road Safety Infrastructure

Issues addressed:

 Transportation planning

 Safety analysis methodologies (e.g., black spot identification) Research projects include:

 Evaluation of High Risk Crash Prediction Methods

 Speed Camera Evaluation

 Effects of speeding and headway related signs on driver

behaviour

(45)

Intelligent Transport Systems

Issues addressed:

 Use of Technology and Information Systems

 Simulation of future ITS Research projects include:

 Predicting vigilance impairment in drivers and operators functioning under monotonous contexts

 Integrating driver and traffic simulation to assess in-

vehicle and road-based level crossing safety interventions

 Development and evaluation of a novel Driver Training

Assessment Tool

(46)

Advanced Driving Simulator

(47)

Advanced Driving Simulator

• Officially unveiled in 2010 ; $1.5 million

• Holden Calais, 8 computers, 3 projectors, mobile platform in 3 dimensions

• Replicates real-time traffic conditions

• Many projects – driver, road conditions,

rail projects

(48)

CARRS-Q Vision

The CARRS-Q vision is to decrease the local, national and international burden

of trauma-related harm

(49)

Questions?

ashleigh.filtness@qut.edu.au

CRICOS No. 00213J

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