Physiotherapy - Research Publications

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    Prolonged Eyelid Closure Episodes during Sleep Deprivation in Professional Drivers
    Alvaro, PK ; Jackson, ML ; Berlowitz, DJ ; Swann, P ; Howard, ME (AMER ACAD SLEEP MEDICINE, 2016)
    STUDY OBJECTIVES: Real life ocular measures of drowsiness use average blink duration, amplitude and velocity of eyelid movements to reflect drowsiness in drivers. However, averaged data may conceal the variability in duration of eyelid closure episodes, and more prolonged episodes that indicate higher levels of drowsiness. The current study aimed to describe the frequency and duration of prolonged eyelid closure episodes during acute sleep deprivation. METHODS: Twenty male professional drivers (mean age ± standard deviation = 41.9 ± 8.3 years) were recruited from the Transport Workers Union newsletter and newspaper advertisements in Melbourne, Australia. Each participant underwent 24 hours of sleep deprivation and completed a simulated driving task (AusEd), the Psychomotor Vigilance Task, and the Karolinska Sleepiness Scale. Eyelid closure episodes during the driving task were recorded and analyzed manually from digital video recordings. RESULTS: Eyelid closure episodes increased in frequency and duration with a median of zero s/h of eyelid closure after 3 h increasing to 34 s/h after 23 h awake. Eyelid closure episodes were short and infrequent from 3 to 14 h of wakefulness. After 17 h of sleep deprivation, longer and more frequent eyelid closure episodes began to occur. Episodes lasting from 7 seconds up to 18 seconds developed after 20 h of wakefulness. Length of eyelid closure episodes was moderately to highly correlated with the standard deviation of lateral lane position, braking reaction time, crashes, impaired vigilance, and subjective sleepiness. CONCLUSIONS: The frequency and duration of episodes of prolonged eyelid closure increases during acute sleep deprivation, with very prolonged episodes after 17 hours awake. Automated devices that assess drowsiness using averaged measures of eyelid closure episodes need to be able to detect prolonged eyelid closure episodes that occur during more severe sleep deprivation.
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    Respiratory adjuncts to NIV in neuromuscular disease
    Sheers, N ; Howard, ME ; Berlowitz, DJ (WILEY, 2019-06)
    Muscle weakness is an intrinsic feature of neuromuscular diseases (NMD). When the respiratory muscles are involved, the ability to take a deep breath is compromised, leading to reduced lung volumes and a restrictive ventilatory impairment. Inspiratory, expiratory and bulbar muscle weakness can also impair cough, which may impede secretion clearance. Non-invasive ventilation (NIV) is an established and indispensable therapy to manage hypoventilation and respiratory failure. The role of other therapies that support respiratory health is less clearly defined, and the evidence of efficacy is also harder to summarize as the underlying data are of a lesser quality. This narrative review appraises the evidence for respiratory therapies in adults with NMD and respiratory system involvement. Techniques that assist lung inflation and augment cough, such as lung volume recruitment (LVR) and mechanical insufflation-exsufflation (MI-E), are a particular focus of this review. The evidence suggests that LVR, MI-E and various combinations thereof have clinical utility generally, but important methodological limitations limit the strength of clinical recommendations and hamper the integration of evidence into practice. Future trials should prospectively assess the long-term impact of LVR and cough augmentation on clinical outcomes and burden of care in addition to lung mechanics, as well as determine clear predictors of benefit from these techniques.
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    Pneumothorax in neuromuscular disease associated with lung volume recruitment and mechanical insufflation-exsufflation
    McDonald, LA ; Berlowitz, DJ ; Howard, ME ; Rautela, L ; Chao, C ; Sheers, N (WILEY, 2019-08)
    A 25-year-old male with Duchenne muscular dystrophy and a 73-year-old male with motor neurone disease both presented with chest pain and increasing dyspnoea following routine mechanical insufflation-exsufflation or lung volume recruitment, on a background of long-term non-invasive ventilation. In each case, chest radiograph revealed a pneumothorax. In both cases the pneumothorax fully resolved following insertion of an intercostal catheter. There was no immediate recurrence and the patients were discharged home and ceased ongoing prophylactic respiratory therapy, although one person had recurrent pneumothoraces subsequently. This rare but serious complication highlights the need for careful risk/benefit analysis by clinicians prescribing these therapies.
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    Stationary gaze entropy predicts lane departure events in sleep-deprived drivers
    Shiferaw, BA ; Downey, LA ; Westlake, J ; Stevens, B ; Rajaratnam, SMW ; Berlowitz, DJ ; Swann, P ; Howard, ME (NATURE PUBLISHING GROUP, 2018-02-02)
    Performance decrement associated with sleep deprivation is a leading contributor to traffic accidents and fatalities. While current research has focused on eye blink parameters as physiological indicators of driver drowsiness, little is understood of how gaze behaviour alters as a result of sleep deprivation. In particular, the effect of sleep deprivation on gaze entropy has not been previously examined. In this randomised, repeated measures study, 9 (4 male, 5 female) healthy participants completed two driving sessions in a fully instrumented vehicle (1 after a night of sleep deprivation and 1 after normal sleep) on a closed track, during which eye movement activity and lane departure events were recorded. Following sleep deprivation, the rate of fixations reduced while blink rate and duration as well as saccade amplitude increased. In addition, stationary and transition entropy of gaze also increased following sleep deprivation as well as with amount of time driven. An increase in stationary gaze entropy in particular was associated with higher odds of a lane departure event occurrence. These results highlight how fatigue induced by sleep deprivation and time-on-task effects can impair drivers' visual awareness through disruption of gaze distribution and scanning patterns.