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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

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]

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

Condition category

Condition code

Public Health

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]

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]

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]

During each of the seven overnight laboratory-based sleep studies.

Primary outcome [2]

Quantitative micro-structural changes of EEG arousal including frequent micro-arousals (3-15 sec EEG changes to faster frequencies) fragmenting sleep.

Timepoint [2]

During each of the seven overnight laboratory-based sleep studies.

Secondary outcome [1]

Sleep macro-structure fragmentation assessed using quantitative spectral analyses via Electroencephalography.

Timepoint [1]

During each of the seven overnight laboratory-based sleep studies.

Secondary outcome [2]

Cardiovascular activation responses assessed using pulse wave amplitude attenuation responses.

Timepoint [2]

During each of the seven overnight laboratory-based sleep studies.

Secondary outcome [3]

Cardiovascular activation associated with isolated k-complexes and full awakenings assessed using Electroencephalography.

Timepoint [3]

During each of the seven-overnight laboratory-based sleep studies.

Secondary outcome [4]

Cortisol responses assessed using salivary cortisol assays (i.e., salivettes).

Timepoint [4]

During each of the seven-overnight laboratory-based sleep studies.

Secondary outcome [5]

Daytime alertness assessed using reaction time (Psychomotor vigilance task; PVT).

Timepoint [5]

In the morning after each of the seven-overnight laboratory-based sleep studies.

Secondary outcome [6]

Daytime sleepiness assessed via the Karolinska Drowsiness Test and Karolinska Sleepiness Scale

Timepoint [6]

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

Sex

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

7/06/2019

Actual

13/06/2019

Date of last participant enrolment

Anticipated

31/10/2020

Actual

15/01/2021

Date of last data collection

Anticipated

31/12/2020

Actual

4/02/2021

Sample size

Target

Accrual to date

Final

Recruitment in Australia

Recruitment state(s)

Funding & Sponsors

Funding source category [1]

Government body

Name [1]

National Health and Medical Research Council

Address [1]

Level 1 16 Marcus Clarke Street Canberra ACT 2601

Country [1]

Australia

Primary sponsor type

University

Name

Flinders University

Address

Sturt Rd
Bedford Park
Adelaide, South Australia 5042

Country

Australia

Secondary sponsor category [1]

None

Name [1]

Address [1]

Country [1]

Ethics approval

Ethics application status

Approved

Ethics committee name [1]

Southern Adelaide Clinical Human Research Ethics Committee (SAC HREC)

Ethics committee address [1]

Human Research Ethics, Room 2A 221 Flinders Medical Centre Level 2, Flinders Medical Centre BEDFORD PARK SA 5042

Ethics committee country [1]

Australia

Date submitted for ethics approval [1]

03/12/2018

Approval date [1]

13/06/2019

Ethics approval number [1]

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

Prof Peter Catcheside

Address

AISH, Flinders University, Level 2, Mark Oliphant Building
5 Laffer Drive, Bedford Park SA 5042

Country

Australia

Phone

+61 8 72218305

Fax

peter.catcheside@flinders.edu.au

Contact person for public queries

Name

Gorica Micic

Address

AISH, Flinders University, Level 2, Mark Oliphant Building
5 Laffer Drive, Bedford Park SA 5042

Country

Australia

Phone

+61 8 82012377

Fax

gorica.micic@flinders.edu.au

Contact person for scientific queries

Name

Peter Catcheside

Address

AISH, Flinders University, Level 2, Mark Oliphant Building
5 Laffer Drive, Bedford Park SA 5042

Country

Australia

Phone

+61 8 72218305

Fax

peter.catcheside@flinders.edu.au

Data sharing statement

Will individual participant data (IPD) for this trial be available (including data dictionaries)?

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?

Doc. No.	Type	Citation	Link	Email	Other Details	Attachment
12520	Ethical approval			gorica.micic@flinders.edu.au

Results publications and other study-related documents

Documents added manually

No documents have been uploaded by study researchers.

Documents added automatically

Source	Title	Year of Publication	DOI
Embase	An experimental investigation on the impact of wind turbine noise on polysomnography-measured and sleep diary-determined sleep outcomes.	2022	https://dx.doi.org/10.1093/sleep/zsac085
Dimensions AI	Establishing the acute physiological and sleep disruption characteristics of wind farm versus road traffic noise disturbances in sleep: a randomized controlled trial protocol	2023	https://doi.org/10.1093/sleepadvances/zpad033

N.B. These documents automatically identified may not have been verified by the study sponsor.

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