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Trial registered on ANZCTR


Registration number
ACTRN12619000501145
Ethics application status
Approved
Date submitted
5/03/2019
Date registered
27/03/2019
Date last updated
13/07/2021
Date data sharing statement initially provided
27/03/2019
Date results information initially provided
13/07/2021
Type of registration
Prospectively registered

Titles & IDs
Public title
The effects of noise disruption on sleep disturbance
Scientific title
Establishing the physiological and sleep disruption characteristics of noise disturbances in sleep
Secondary ID [1] 297104 0
GNT1113571
Universal Trial Number (UTN)
U1111-1229-6126
Trial acronym
Not applicable
Linked study record

Health condition
Health condition(s) or problem(s) studied:
Low frequency noise effects on sleep 311115 0
Condition category
Condition code
Public Health 309745 309745 0 0
Other public health

Intervention/exposure
Study type
Interventional
Description of intervention(s) / exposure
These experiments are specifically designed to establish wind farm versus traffic noise effects on sleep efficiency (macro-structure), and micro-arousal responses to each noise type at equivalent A-weighted Sound Pressure Levels (SPL). Twenty participants from each of the 4 experimental groups will be asked to attend the laboratory for 7 consecutive night sleep studies (4 experimental nights, each with an intervening recovery night). Experimental nights will consist of; prolonged wind farm and traffic noise exposures (WF and T nights), a noise fragmentation night (i.e., randomised and counterbalanced WFN and TN at various SPL, along with silent control exposures), and a control night in random order. Participants will be instrumented for sleep and physiological measures prior to going to bed at their habitual bedtime each night and instructed that they may or may not notice any noises on any of the nights. Experimental noise exposures will only commence once polysomnographically defined stable (>2 min) stage 2 or deeper sleep is already established (or re-established) to avoid noise interference with sleep onset, which we do not believe can be adequately blinded in full night noise exposure experiments. WFN and TN arousal thresholds in deep and stage 2 sleep will be measured on each experimental night using an established brief noise-escalation protocol.

WFN and TN nights will be constructed to approximate worst case noise exposure nights (from existing recordings) using 3-min periods of pre-recorded noises with minimal time-variability, randomised into a sequence containing both no noise (control exposures) and A-weighted SPLs up to original recording maxima in 3-6 dBA increments. We will use fade-in over the first 30-sec and A-weight SPL matching between noise types and include noises both unfiltered and filtered to exclude low frequencies <160 Hz and infrasound <20 Hz. The primary outcome is sleep efficiency (sleep time as a % of each 5 min exposure), which requires fixed/ongoing exposures irrespective of arousals or awakenings.

On sleep fragmentation nights pre-recorded short (~20-sec) wind farm and traffic noise events will be replayed to more specifically examine physiological activation responses to brief noise events. Noises will be replayed with varying SPLs and filtering similar to WFN and TN nights to span the full range of physiological activation responses from no discernible to “sub-cortical”, micro-arousal and full-awakening responses, with as many replicates as possible throughout the night. This protocol is specifically designed to allow construction of noise dose (SPL)-response curves as a function of stimulus type and sleep stage.

In the morning, participants will be asked how well they slept compared to their usual sleep, and to recall what type and number of sounds if any they heard over the previous night to test blinding effectiveness. Salivary samples for cortisol measurements will be collected over the first hour and at 12 hours after initial morning awakening. Between salivary samples in the first hour participants will also undergo a brief psychomotor vigilance task (PVT), and measures of daytime sleepiness. Daytime in-laboratory noise detection and perception tests will commence following breakfast, after which participants will be free to leave the laboratory for the remainder of the day before returning for their next study night.

Daytime in-laboratory noise detection and perception tests will compare perceptual responses (acuity, annoyance, loudness and level of acceptance for sleep) and measures of physiological disturbances (heart rate, blood pressure, vasoconstriction responses) of a range of pre-recorded wind farm and traffic noise samples replayed in random order to participants from each survey respondent group. Methods are based largely on previous studies assessing noise annoyance, with the addition of EEG and cardiovascular measurements.
Intervention code [1] 313413 0
Diagnosis / Prognosis
Comparator / control treatment
The control group will consist of participants who live in a quiet rural exposure area. They will be determined and selected by an initial survey-based study.
Control group
Active

Outcomes
Primary outcome [1] 318707 0
The primary outcome will be EEG measures of sleep quality including sleep efficiency, calculated as total sleep time expressed as a percentage of time available for sleep under each noise exposure condition.
Timepoint [1] 318707 0
During each of the seven overnight laboratory-based sleep studies.
Primary outcome [2] 318708 0
Quantitative micro-structural changes of EEG arousal including frequent micro-arousals (3-15 sec EEG changes to faster frequencies) fragmenting sleep.
Timepoint [2] 318708 0
During each of the seven overnight laboratory-based sleep studies.
Secondary outcome [1] 365949 0
Sleep macro-structure fragmentation assessed using quantitative spectral analyses via Electroencephalography.
Timepoint [1] 365949 0
During each of the seven overnight laboratory-based sleep studies.
Secondary outcome [2] 366083 0
Cardiovascular activation responses assessed using pulse wave amplitude attenuation responses.
Timepoint [2] 366083 0
During each of the seven overnight laboratory-based sleep studies.
Secondary outcome [3] 368667 0
Cardiovascular activation associated with isolated k-complexes and full awakenings assessed using Electroencephalography.
Timepoint [3] 368667 0
During each of the seven-overnight laboratory-based sleep studies.
Secondary outcome [4] 368668 0
Cortisol responses assessed using salivary cortisol assays (i.e., salivettes).
Timepoint [4] 368668 0
During each of the seven-overnight laboratory-based sleep studies.
Secondary outcome [5] 368669 0
Daytime alertness assessed using reaction time (Psychomotor vigilance task; PVT).
Timepoint [5] 368669 0
In the morning after each of the seven-overnight laboratory-based sleep studies.
Secondary outcome [6] 368671 0
Daytime sleepiness assessed via the Karolinska Drowsiness Test and Karolinska Sleepiness Scale
Timepoint [6] 368671 0
In the morning after each of the seven-overnight laboratory-based sleep studies.

Eligibility
Key inclusion criteria
• Age > 17 years; and
• Freely given informed consent; and
• One of the following:
- Live < 10 km from a wind turbine; or
- Live in a quiet rural area; or
- Live adjacent to a busy road traffic corridor
Minimum age
18 Years
Maximum age
No limit
Gender
Both males and females
Can healthy volunteers participate?
Yes
Key exclusion criteria
• Language difficulties that might preclude fully informed consent.
• Self-reported sleep disorders other than Insomnia (e.g., Sleep Apnoea, Restless Legs Syndrome)
• Pregnancy/lactation
• Night shift work
• Trans meridian travel
• Trans-meridian travel (equal to or greater than 2 time zones) in the last 2 months

Study design
Purpose of the study
Diagnosis
Allocation to intervention
Randomised controlled trial
Procedure for enrolling a subject and allocating the treatment (allocation concealment procedures)
Not applicable
Methods used to generate the sequence in which subjects will be randomised (sequence generation)
Noise samples will be block-randomised and counterbalanced within conditions and across laboratory nights using the random sequence generator (i.e., randperm(k) function) in MATLAB software.
Masking / blinding
Blinded (masking used)
Who is / are masked / blinded?
The people receiving the treatment/s
The people administering the treatment/s
The people assessing the outcomes
The people analysing the results/data
Intervention assignment
Crossover
Other design features
Not applicable
Phase
Not Applicable
Type of endpoint(s)
Statistical methods / analysis
The primary outcome will be sleep efficiency (sleep time expressed as a percentage of time available for sleep under each noise exposure condition) with the propensity for and magnitude of EEG activation (sub-cortical events, micro-arousals and full-awakenings), arousal thresholds to wind farm versus traffic noise, and cardiovascular responses as key secondary outcomes. Comparisons between groups and conditions will be via linear mixed effects model analyses, with night, sleep stage and noise conditions as repeated factors within-subjects, individuals entered as a random effect to account for correlated measures and an overall 2-tailed Type I error rate of 5%. Kaplan-Meier and Cox regression analyses will be used to assess EEG (sub-cortical, micro-arousal and awakening) event-free “survival” to each different noise stimulus type between groups and sleep stages.
Sleep efficiency shows low between subject variability (SD ~10%), large insomnia treatment effects and low within-subject variability over consecutive nights (~3%). By repeated measures design we estimate that 4 groups of 20 participants has 80% power to detect an 11% (clinically significant) between group effects, and substantially greater power to detect with-in subject differences between noise interventions.

Recruitment
Recruitment status
Completed
Date of first participant enrolment
Anticipated
Actual
Date of last participant enrolment
Anticipated
Actual
Date of last data collection
Anticipated
Actual
Sample size
Target
Accrual to date
Final
Recruitment in Australia
Recruitment state(s)
SA

Funding & Sponsors
Funding source category [1] 301670 0
Government body
Name [1] 301670 0
National Health and Medical Research Council
Address [1] 301670 0
Level 1 16 Marcus Clarke Street Canberra ACT 2601
Country [1] 301670 0
Australia
Primary sponsor type
University
Name
Flinders University
Address
Sturt Rd
Bedford Park
Adelaide, South Australia 5042
Country
Australia
Secondary sponsor category [1] 301386 0
None
Name [1] 301386 0
Address [1] 301386 0
Country [1] 301386 0

Ethics approval
Ethics application status
Approved
Ethics committee name [1] 302389 0
Southern Adelaide Clinical Human Research Ethics Committee (SAC HREC)
Ethics committee address [1] 302389 0
Human Research Ethics, Room 2A 221 Flinders Medical Centre Level 2, Flinders Medical Centre BEDFORD PARK SA 5042
Ethics committee country [1] 302389 0
Australia
Date submitted for ethics approval [1] 302389 0
03/12/2018
Approval date [1] 302389 0
13/06/2019
Ethics approval number [1] 302389 0

Summary
Brief summary
Good sleep is essential for normal daytime functioning and health and effects of sleep disorders and sensory disturbances such as traffic noise on sleep quality and health outcomes are well known. Expansion of wind farm facilities in Australia has been associated with widespread community complaints regarding sleep disturbance and adverse health effects potentially attributable to wind farms operating in a normally quiet rural environment. Wind farm noise exposure, including audible and potentially inaudible low frequency components, clearly has the potential to adversely affect sleep, health and well-being through two main plausible and inter-related mechanisms; chronic sleep fragmentation from frequent physiological activation responses to sensory disturbances in sleep, and chronic insomnia which could potentially develop more gradually over time in sensitised individuals. However, as outlined in the NHMRC rapid review of the evidence, data from well-designed studies using objective measures of sleep and sound are remarkably lacking and are clearly now needed to definitively establish the sleep disruption characteristics of wind farm noise compared to other noise disturbances in sleep. This project will, for the first time, use direct electroencephalographic (EEG) and cardiovascular measurements to systematically evaluate the sleep disruption and physiological activation response characteristics of wind farm noise during sleep. Groups of individuals with and without prior wind farm noise exposure will be studied in carefully controlled laboratory conditions using pre-recorded and accurately-reproduced wind-farm noise, including and excluding low frequency components and infrasound. Dose-response characteristics will also be evaluated against more ubiquitous traffic noise in sleep. Potential predictors of sleep disturbance responses such as sensory acuity, annoyance and physiological activation response to noise presented during wakefulness will also be evaluated.
Trial website
https://www.flinders.edu.au/wind-farm-noise-study/
Trial related presentations / publications
Public notes

Contacts
Principal investigator
Name 90066 0
Prof Peter Catcheside
Address 90066 0
AISH, Flinders University, Level 2, Mark Oliphant Building
5 Laffer Drive, Bedford Park SA 5042
Country 90066 0
Australia
Phone 90066 0
+61 8 72218305
Fax 90066 0
Email 90066 0
peter.catcheside@flinders.edu.au
Contact person for public queries
Name 90067 0
Dr Gorica Micic
Address 90067 0
AISH, Flinders University, Level 2, Mark Oliphant Building
5 Laffer Drive, Bedford Park SA 5042
Country 90067 0
Australia
Phone 90067 0
+61 8 82012377
Fax 90067 0
Email 90067 0
gorica.micic@flinders.edu.au
Contact person for scientific queries
Name 90068 0
Prof Peter Catcheside
Address 90068 0
AISH, Flinders University, Level 2, Mark Oliphant Building
5 Laffer Drive, Bedford Park SA 5042
Country 90068 0
Australia
Phone 90068 0
+61 8 72218305
Fax 90068 0
Email 90068 0
peter.catcheside@flinders.edu.au

Data sharing statement
Will individual participant data (IPD) for this trial be available (including data dictionaries)?
No
No/undecided IPD sharing reason/comment
There are ethical and logistical considerations that would prevent IPD sharing. Mechanisms to enable public data sharing for this project do not exist.
What supporting documents are/will be available?
Ethical approval
How or where can supporting documents be obtained?
Type [1] 12520 0
Ethical approval
Citation [1] 12520 0
Link [1] 12520 0
Email [1] 12520 0
gorica.micic@flinders.edu.au
Other [1] 12520 0
Attachment [1] 12520 0
Summary results
Have study results been published in a peer-reviewed journal?
No
Other publications
Have study results been made publicly available in another format?
Results – basic reporting
Results – plain English summary