Fibromyalgia SyndromeSoundsPainFMNCT07037134
Impact of Auditory Environments on Pain in Fibromyalgia: a 4×4 Crossover Trial
A study testing Natural soundscape exposure, Urban soundscape exposure and Broadband sound exposure in people with Fibromyalgia Syndrome, run by Universidad de Granada at 1 site in Spain.
Trial summary
This study examines whether different types of sounds can help reduce pain in people with fibromyalgia, a chronic condition that causes widespread pain and increased sensitivity to sensory experiences. Fibromyalgia affects approximately 2-3% of the global population and has limited treatment options. Read more about this study
- Who is it for?
- Ages 18 years and older
- Conditions the study is for
- Fibromyalgia Syndrome
- What is being tested?
- Natural soundscape exposure, Urban soundscape exposure and Broadband sound exposure
- Type of treatment
- Injection or infusion
- Could I receive a placebo?
- Yes, some participants may receive a placebo
- How many people
- 88 participants
- Where
- 1 siteSpain
- Study dates
- 4 Aug 2025to 31 Oct 2025
- Phase
- Interventional
- Are there results?
- None posted in the registry
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 years and older
- All sexes
- No healthy volunteers
- Adult, Older adult
Who may be able to join
- A diagnosis of fibromyalgia syndrome, documented in the medical record provided by the participant prior to enrollment.
- Moderate or greater pain intensity during the preceding week, defined as a score higher than 3 on an 11-point Numeric Rating Scale.
- Normal hearing confirmed by a hearing test, defined as a mean threshold of ≤ 20 dB HL at 0.125, 0.25, 0.5, 1, 2, 4, 6, and 8 kHz.
- Ability to communicate in Spanish.
- Provision of signed written informed consent to participate in the research.
Who cannot join
- A diagnosis of misophonia or auditory processing disorders, as documented in the participant's medical record.
- Concurrent neuropathic or acute pain.
- Severe cognitive impairment, defined as a Mini-Mental State Examination score ≤ 17.
- Severe psychiatric disorders in the symptomatic phase.
- History of substance abuse in the past 12 months or current substance use disorder as reported by the participant.
- Changes in ongoing therapy during or within one month prior to study enrollment per participant self-reports.
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- Central nervous system disorders.
- Any other serious or unstable medical condition that could interfere with study participation.
- Known allergies or hypersensitivity to study materials.
- Pregnancy, lactation, or being within three months postpartum at the time of study enrollment.
Trial locations and contacts
1 site in 1 country.
Spain1 site
Faculty of Health Sciences, University of Granada
Granada, Granada, 18016
About this study
Official title: Impact of Auditory Environments on the Functioning of Pain Mechanisms in Fibromyalgia Syndrome: a Randomized, Triple-blind, Placebo-controlled 4×4 Crossover Trial
This study examines whether different types of sounds can help reduce pain in people with fibromyalgia, a chronic condition that causes widespread pain and increased sensitivity to sensory experiences. Fibromyalgia affects approximately 2-3% of the global population and has limited treatment options. Recent research suggests that environmental sounds might have the capacity to influence pain perception, but their effects in chronic pain conditions remain largely unexplored. Such research could lead to new, non-invasive, sound-based approaches for managing fibromyalgia pain and inform the design of healthier acoustic environments for people with chronic pain conditions.
The study will compare four different sound environments: natural soundscapes (like birdsong and rainfall), urban soundscapes (like traffic and background conversation), broadband sounds (white or pink noise), and silence (as a neutral/control condition with intended placebo effect). Researchers want to know if these different sound environments can change how people with fibromyalgia experience pain and if some environmental sounds might be more helpful than others.
Each participant will experience all four sound conditions in a random order, with one session per week over four weeks. With this study design, each participant acts as their own control, which reduces differences between individuals and increases the reliability of the results. During each 20-minute session, participants will listen to the assigned sounds through a high-fidelity sound reproduction setup using headphones while lying comfortably on a padded therapy table in a controlled laboratory setting. Before and after each sound exposure, researchers measure pain intensity and sensitivity using standardized assessments to determine whether and how different sound environments, if any, might offer pain relief.
Read the detailed description
This protocol investigates the potential modulatory effects of distinct auditory environments on pain processing mechanisms in individuals with fibromyalgia syndrome. The study is grounded in emerging neuroscientific evidence suggesting that auditory stimuli can influence pain perception through direct neural pathways between the auditory cortex and pain-processing regions.
Soundscapes-defined as acoustic environments perceived, experienced, and interpreted within specific contexts-are categorized as natural or anthropogenic based on their origin for research purposes. Natural soundscapes comprise elements such as biophonies (non-human animal sounds) and geophonies (non-living natural elements), while urban soundscapes feature anthropophonies (human-generated sounds) and technophonies (mechanical sources). Recent neuroimaging research has demonstrated that these different soundscape categories elicit distinct neural signatures and may differentially shape intrinsic brain dynamics.
Fibromyalgia syndrome presents a particularly relevant clinical model for investigating auditory-pain interactions due to its characteristic heightened sensitivity to non-noxious sensory input. Preclinical evidence has identified direct neural pathways between the auditory cortex and pain-processing regions, with rodent studies showing that 20-minute broadband sound exposure significantly increases mechanical pain thresholds through mechanisms involving reduced thalamic activity. Human studies have similarly documented analgesic effects of auditory stimulation across both acute experimental pain and chronic pain conditions.
The general objective of this study is to:
GO1. Investigate the differential effects of controlled auditory environmental exposures-natural soundscapes, urban soundscapes, broadband sound, and silence-on the functioning of altered pain mechanisms in individuals with fibromyalgia syndrome, evaluated through clinical outcomes (pain intensity and perceived improvement) and experimental indices of pain processing (quantitative sensory testing measures).
The specific objectives are to:
SO1. Compare the effects of natural and urban soundscapes against broadband sound (active comparator) and silence (attention-placebo control) on the functioning of pain mechanisms.
SO2. Determine the relative efficacy of natural versus urban soundscapes in modulating the functioning of pain mechanisms in individuals with fibromyalgia syndrome.
SO3. Characterize the magnitude and direction of potential within-condition changes in the functioning of pain mechanisms following exposure to natural and urban soundscapes.
The primary hypothesis is:
PH1. Distinct auditory environmental exposures-natural soundscapes, urban soundscapes, broadband sound, and silence-will differentially modulate self-reported pain intensity in individuals with fibromyalgia syndrome, with the following specific hypothesized relationships:
PH1.1. Natural soundscape exposure will demonstrate superior analgesic efficacy compared to attention-placebo control.
PH1.2. Natural soundscape exposure will demonstrate superior analgesic efficacy compared to broadband sound exposure.
PH1.3. The analgesic effects of urban soundscape exposure will not significantly differ from attention-placebo control.
PH1.4. The analgesic effects of urban soundscape exposure will not significantly differ from broadband sound exposure.
PH1.5. Natural soundscape exposure will demonstrate superior analgesic efficacy compared to urban soundscape exposure.
The secondary hypotheses are:
SH1. Exposure to natural soundscapes will lead to significant pre-post improvements in both clinical outcomes and experimental indices of pain processing.
SH2. Exposure to urban soundscapes will demonstrate non-significant pre-post effects in both clinical outcomes and experimental indices of pain processing.
The study design optimizes statistical efficiency by allowing within-subject comparisons while controlling for period effects. The auditory exposure sessions are conducted in a controlled laboratory environment, maintaining a consistent room temperature and relative humidity.
To recruit participants, voluntary response, convenience, and snowball sampling methods will be employed. An a priori power analysis was conducted using G*Power v3.1.9.7. The sample size estimation is based on a Cohen's f effect size of 0.516, derived from the previous findings on the effect of nature sounds on pain in patients with chronic pain. A minimum of 58 participants is required to provide a power of 90% to adequately detect the determined pre-post difference at a two-tailed alpha level of .05. Allowing for an anticipated attrition rate of approximately one-third-including potential dropout, loss to follow-up, clinical reasons, and operational issues-a total of 88 participants will be recruited.
The assessment protocol follows International Association for the Study of Pain consensus guidelines and incorporates core outcome domains recommended for chronic pain trials. It covers both clinical outcomes (pain intensity and perceived improvement) and experimental indices of pain processing (quantitative sensory testing measures). These measures collectively provide a comprehensive evaluation of both subjective pain experience and biomarkers of pain processing, performed by a trained evaluator.
The primary analytical strategy will use linear mixed-effects models to examine change-from-baseline scores across conditions. Fixed effects will include treatment, period, sequence, and their interaction to detect potential carryover effects, while participants will be modeled with random intercepts. In the absence of carryover, a simplified model excluding the interaction term will be applied. Between-condition effects will be assessed via estimated marginal means with Bonferroni-adjusted pairwise comparisons. Sensitivity analyses will introduce the covariates to examine their influence on treatment effects. Within-condition (pre-post) changes will be evaluated using paired t-tests or Wilcoxon signed-rank tests, depending on data distribution.
To meet statistical assumptions, distributions of quantitative sensory testing outcomes-including mechanical pain sensitivity, temporal summation of pain, and pressure pain detection thresholds and intensity ratings-will be log-transformed, consistent with established methods. A small constant will be added to variables with potential zero values prior to transformation. For presentation purposes, transformed values will be back-converted to original units in descriptive outputs. All hypothesis testing will be two-sided with a Type I error rate of 5%, and analyses will follow the intention-to-treat principle. Multiple imputation will be considered if missingness is not at random.
This study is considered as minimal risk. No serious adverse events are expected. All participants may withdraw at any time without justification or impact on healthcare access. Discontinuation may occur at participants' request or in response to adverse events or protocol violations. Adverse events will be monitored throughout. Given the low-risk profile, oversight will be managed by the principal investigator; no independent safety board is planned. Safety monitoring will involve systematic documentation of all treatment-emergent and spontaneously reported adverse events throughout the study period.
To our knowledge, this study would represent one of the first investigations conceptualizing everyday soundscapes as environmental determinants potentially capable of modulating pain processing in chronic pain populations. The findings may contribute to several domains:
- Theoretical advancement in understanding auditory-pain interactions and their environmental influences.
- Development of novel, non-pharmacological auditory-based interventions for pain management in fibromyalgia syndrome.
- Informing environmental health policies and acoustic design strategies for healthcare settings.
- Contributing to the emerging field of environmental neuroscience by informing whether and how environmental sounds influence chronic pain processing.
- Conditions
- Fibromyalgia Syndrome
- Being tested
- Natural soundscape exposure, Urban soundscape exposure, Broadband sound exposure, Blank tape attention placebo control
- Keywords
- Acoustic environment, Audioanalgesia, Blank tape, Broadband noise, Chronic primary pain, Clinical trial, Crossover, Fibromyalgia, Natural sound, Pain modulation, Pink noise, Soundscape, Urban sound, White noise
- Medical subject headings
- Fibromyalgia, Chronic Pain
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Natural soundscape exposureOther
Also called Experimental intervention N
Participants receive a standardized 20-minute auditory exposure to curated natural soundscapes via high-fidelity open-back reference headphones powered by a DAC/amplifier and corrected for frequency response using calibration software. Participants are randomly assigned one of 22 recordings. Each includes 10-second fade-in/out effects and is calibrated to 45-55 dB. The stereo recordings (320-kbps MP3, 48 kHz/24-bit) feature biophony (e.g., bird vocalizations) and geophony (e.g., rainfall), free of urban sounds and selected for ecological validity based on predefined criteria: (i) recognizable/context-specific sounds; (ii) culturally neutral; (iii) foreground presence and depth; (iv) no prolonged silence; (v) no technical artifacts. During exposure, they lie supine in a 60° Fowler's position on a therapy table, with sensory input minimized through auditory isolation and controlled ambient conditions. The session involves active listening under continuous researcher supervision.
Urban soundscape exposureOther
Also called Experimental intervention U
Participants receive a standardized 20-minute auditory exposure to curated urban soundscapes, using the same equipment and technical specifications as all other intervention conditions. Each participant is randomly assigned one of 22 recordings, calibrated to 60-70 dB (Leq,20min). The recordings feature anthropophony (e.g., unintelligible background speech) and technophony (e.g., transportation-related sounds), free of natural sounds and selected for ecological validity based on the same predefined criteria as the natural soundscapes. To prevent semantic processing, participants are pre-screened and post-session reconfirmed to ensure they do not understand the languages used. During exposure, participants lie supine in a 60° Fowler's position on a therapy table, with sensory input minimized through auditory isolation and controlled ambient conditions. The session involves active listening and is conducted under continuous researcher supervision.
Broadband sound exposureOther
Also called Active comparator
Participants receive a standardized 20-minute auditory exposure to broadband sounds (i.e., white or pink noise), using the same equipment and technical specifications as all other intervention conditions. Each participant is randomly assigned to one of the two noise types, with equal distribution across conditions. The stimuli are generated using professional audio software and calibrated to 50 dB (Leq,20min). During exposure, participants lie supine in a 60° Fowler's position on a therapy table, with sensory input minimized through auditory isolation and controlled ambient conditions. The session involves active listening and is conducted under continuous researcher supervision.
Blank tape attention placebo controlOther
Also called Placebo comparator
Participants receive a standardized 20-minute exposure to blank audio (silence), using the same equipment and technical specifications as all other intervention conditions. At study onset, participants are informed they will hear a range of environmental sounds, including some that may be inaudible (i.e., present but beyond the range of human hearing). During the placebo condition, a blank recording is played, producing silence, while participants remain unaware of whether they are receiving an active or placebo stimulus. This attention-control condition ensures procedural consistency while delivering no auditory stimulation. During exposure, participants lie supine in a 60° Fowler's position on a therapy table, with sensory input minimized through auditory isolation and controlled ambient conditions. The session involves active listening and is conducted under continuous researcher supervision.
| Study group | Role | What they receive |
|---|---|---|
| Sequence NBPU | Other | Participants assigned to this sequence receive natural soundscape exposure in Week 1, broadband sound exposure in Week 2, placebo control (blank tape) in Week 3, and urban soundscape exposure in Week 4. Each session lasts 20 minutes, with one-week washout intervals between sessions. Receives: Other: Natural soundscape exposure; Other: Urban soundscape exposure; Other: Broadband sound exposure; Other: Blank tape attention placebo control |
| Sequence UPBN | Other | Participants assigned to this sequence receive urban soundscape exposure in Week 1, placebo control (blank tape) in Week 2, broadband sound exposure in Week 3, and natural soundscape exposure in Week 4. Each session lasts 20 minutes, with one week washout intervals between sessions. Receives: Other: Natural soundscape exposure; Other: Urban soundscape exposure; Other: Broadband sound exposure; Other: Blank tape attention placebo control |
| Sequence BUNP | Other | Participants assigned to this sequence receive broadband sound exposure in Week 1, urban soundscape exposure in Week 2, natural soundscape exposure in Week 3, and placebo control (blank tape) in Week 4. Each session lasts 20 minutes, with one week washout intervals between sessions. Receives: Other: Natural soundscape exposure; Other: Urban soundscape exposure; Other: Broadband sound exposure; Other: Blank tape attention placebo control |
| Sequence PNUB | Other | Participants assigned to this sequence receive placebo control (blank tape) in Week 1, natural soundscape exposure in Week 2, urban soundscape exposure in Week 3, and broadband sound exposure in Week 4. Each session lasts 20 minutes, with one week washout intervals between sessions. Receives: Other: Natural soundscape exposure; Other: Urban soundscape exposure; Other: Broadband sound exposure; Other: Blank tape attention placebo control |
What is being measured
The primary outcome is the main question the study is designed to answer.
Pain intensity
The primary outcome measure assesses acute changes in subjective pain intensity following each auditory intervention. Participants mark their current pain level on a 100-mm Visual Analog Scale anchored from "no pain" to "the worst pain imaginable". The scale is scored as the distance in millimeters from the left end, with lower scores corresponding to lower perceived pain.
Measured: Change from immediately before to immediately after each 20-minute intervention session during each of the four crossover periods
Secondary outcomes (4)
Patient global impression of change
Participants rate overall change on a seven-point Likert scale ranging from one ("very much improved") to seven ("very much worse"). Lower scores indicate greater perceived improvement.
Measured: Assessed immediately after each 20-minute intervention session during each of the four crossover periods
Mechanical pain sensitivity
Mechanical pain sensitivity is assessed using a response-dependent procedure with a 180-gram Semmes-Weinstein monofilament, involving three perpendicular stimulations to the cheek on each side, with 10-second interstimulus intervals. After each application, participants rate the perceived pain intensity on a 100-mm Visual Analog Scale. This sequence is repeated three times, and the geometric mean of the three ratings is calculated for each side. The arithmetic mean of the bilateral geometric means is registered as the mechanical pain sensitivity. Lower values indicate lower mechanical pain sensitivity.
Measured: Change from immediately before to immediately after each 20-minute intervention session during each of the four crossover periods
Temporal summation of pain
Temporal summation is assessed using a response-dependent procedure with a 180-gram Semmes-Weinstein monofilament applied to the left thenar eminence. First, a single stimulus is administered, followed by participant rating of perceived pain intensity on a 100-mm Visual Analog Scale. After a 30-second interval, a series of 10 stimuli is delivered at 1 Hz to the same location, followed by an overall pain rating. The temporal summation index is calculated as the difference between the pain ratings for the stimulus series and the single stimulus. Lower values indicate reduced central pain facilitation.
Measured: Change from immediately before to immediately after each 20-minute intervention session during each of the four crossover periods
Pressure pain detection thresholds and intensity ratings
Pressure pain detection thresholds are assessed using a digital pressure algometer equipped with a one-cm² circular flat probe, following the method of limits. Assessment sites include the midpoint of the upper trapezius and the medial fat pad of the knee, measured bilaterally. Pressure is applied at a constant rate of 50 kPa/sec until participants report the first perception of pain, with a maximum cutoff of 1000 kPa for safety. Three trials are performed per site, with the first trial discarded. The arithmetic mean of the second and third trials across all four sites is recorded as the pressure pain threshold. Following each application, participants rate the evoked pain intensity using a 100-mm Visual Analog Scale. The mean of the second and third intensity ratings across all sites is registered as the pressure-evoked pain intensity. Higher threshold values indicate lower pain sensitivity, while lower intensity scores reflect reduced perceived pain.
Measured: Change from immediately before to immediately after each 20-minute intervention session during each of the four crossover periods
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted25 Jun 2025
- Study start4 Aug 2025
- Primary completion31 Oct 2025
- Study completion31 Oct 2025
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Publications (1)Papers the sponsor has linked to this study.
- Other trials for Fibromyalgia SyndromeStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Crossover
- Model description
- This study employs a randomized, triple-blind, placebo-controlled crossover design based on a 4×4 Williams Latin square. Each participant receives all four interventions in a randomized, balanced sequence across four periods, with one-week washout intervals separating each session to mitigate residual effects. The design ensures equal representation of each condition across periods and sequences (uniform within sequences and periods), controlling for first-order carryover effects. This model supports within-subject comparisons, minimizes interindividual variability and confounding, and improves statistical power and internal validity using robust outcome analysis via mixed-effects modeling.
- Masking
- Triple blind
- Who is masked
- Care provider, Investigator, Outcomes assessor
- Enrolment
- 88 participants (actual)
Sponsor and investigators
- Lead sponsor
- Universidad de Granada
- Sponsor type
- University, hospital or other
- Responsible party
- Principal investigator, José Manuel Pérez Mármol, Universidad de Granada
- Investigators
- José Manuel Pérez Mármol, PhD, Principal investigator, Department of Physiotherapy, Faculty of Health Sciences, University of Granada
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07037134
- Sponsor's protocol ID
- FIBRO-PAIN-SOUND-2025
- Acronym
- SoundsPainFM
- Status last verified
- Nov 2025
- First submitted
- 9 Jun 2025
- Last updated
- 17 Nov 2025
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- Yes: All individual participant data collected during the trial will be shared after de-identification, in accordance with executed data sharing agreements that require adherence to confidentiality, data protection, and non-reidentification standards equivalent to those of the originating study. The data to be shared will include baseline participant characteristics, outcome measures, covariates, and safety data. Only data necessary to replicate study findings or to conduct methodologically sound secondary analyses will be made available. The shared dataset will be accompanied by a comprehensive data dictionary that defines all variables, coding schemes, and measurement protocols to ensure full interpretation and appropriate use of the data.
Publications
Gungormus DB, Perez-Marmol JM. The impact of everyday acoustic environments on chronic pain mechanisms in fibromyalgia: a randomized, triple-blind, placebo-controlled 4 x 4 crossover trial. Pain. 2026 Aug 1;167(8):1941-1957. doi: 10.1097/j.pain.0000000000004042. Epub 2026 Jun 26.
PubMed 42350308
Study at a glance
From the registry record, last updated by the sponsor on 17 Nov 2025. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Impact of Auditory Environments on the Functioning of Pain Mechanisms in Fibromyalgia Syndrome: a Randomized, Triple-blind, Placebo-controlled 4×4 Crossover Trial
- ClinicalTrials.gov ID
- NCT07037134
- Acronym / sponsor ID
- SoundsPainFM / FIBRO-PAIN-SOUND-2025
- Conditions
- Fibromyalgia Syndrome
- Keywords
- Acoustic environment, Audioanalgesia, Blank tape, Broadband noise, Chronic primary pain, Clinical trial, Crossover, Fibromyalgia
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 88 participants (actual)
- Lead sponsor
- Universidad de GranadaUniversity, hospital or other
- Study start
- 4 Aug 2025 (actual)
- Primary completion
- 31 Oct 2025 (actual)
- Study completion
- 31 Oct 2025 (actual)
- First posted
- 25 Jun 2025 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
This study examines whether different types of sounds can help reduce pain in people with fibromyalgia, a chronic condition that causes widespread pain and increased sensitivity to sensory experiences. Fibromyalgia affects approximately 2-3% of the global population and has limited treatment options. Recent research suggests that environmental sounds might have the capacity to influence pain perception, but their effects in chronic pain conditions remain largely unexplored. Such research could lead to new, non-invasive, sound-based approaches for managing fibromyalgia pain and inform the design of healthier acoustic environments for people with chronic pain conditions.
The study will compare four different sound environments: natural soundscapes (like birdsong and rainfall), urban soundscapes (like traffic and background conversation), broadband sounds (white or pink noise), and silence (as a neutral/control condition with intended placebo effect). Researchers want to know if these different sound environments can change how people with fibromyalgia experience pain and if some environmental sounds might be more helpful than others.
Each participant will experience all four sound conditions in a random order, with one session per week over four weeks. With this study design, each participant acts as their own control, which reduces differences between individuals and increases the reliability of the results. During each 20-minute session, participants will listen to the assigned sounds through a high-fidelity sound reproduction setup using headphones while lying comfortably on a padded therapy table in a controlled laboratory setting. Before and after each sound exposure, researchers measure pain intensity and sensitivity using standardized assessments to determine whether and how different sound environments, if any, might offer pain relief.
Detailed description
This protocol investigates the potential modulatory effects of distinct auditory environments on pain processing mechanisms in individuals with fibromyalgia syndrome. The study is grounded in emerging neuroscientific evidence suggesting that auditory stimuli can influence pain perception through direct neural pathways between the auditory cortex and pain-processing regions.
Soundscapes-defined as acoustic environments perceived, experienced, and interpreted within specific contexts-are categorized as natural or anthropogenic based on their origin for research purposes. Natural soundscapes comprise elements such as biophonies (non-human animal sounds) and geophonies (non-living natural elements), while urban soundscapes feature anthropophonies (human-generated sounds) and technophonies (mechanical sources). Recent neuroimaging research has demonstrated that these different soundscape categories elicit distinct neural signatures and may differentially shape intrinsic brain dynamics.
Fibromyalgia syndrome presents a particularly relevant clinical model for investigating auditory-pain interactions due to its characteristic heightened sensitivity to non-noxious sensory input. Preclinical evidence has identified direct neural pathways between the auditory cortex and pain-processing regions, with rodent studies showing that 20-minute broadband sound exposure significantly increases mechanical pain thresholds through mechanisms involving reduced thalamic activity. Human studies have similarly documented analgesic effects of auditory stimulation across both acute experimental pain and chronic pain conditions.
The general objective of this study is to:
GO1. Investigate the differential effects of controlled auditory environmental exposures-natural soundscapes, urban soundscapes, broadband sound, and silence-on the functioning of altered pain mechanisms in individuals with fibromyalgia syndrome, evaluated through clinical outcomes (pain intensity and perceived improvement) and experimental indices of pain processing (quantitative sensory testing measures).
The specific objectives are to:
SO1. Compare the effects of natural and urban soundscapes against broadband sound (active comparator) and silence (attention-placebo control) on the functioning of pain mechanisms.
SO2. Determine the relative efficacy of natural versus urban soundscapes in modulating the functioning of pain mechanisms in individuals with fibromyalgia syndrome.
SO3. Characterize the magnitude and direction of potential within-condition changes in the functioning of pain mechanisms following exposure to natural and urban soundscapes.
The primary hypothesis is:
PH1. Distinct auditory environmental exposures-natural soundscapes, urban soundscapes, broadband sound, and silence-will differentially modulate self-reported pain intensity in individuals with fibromyalgia syndrome, with the following specific hypothesized relationships:
PH1.1. Natural soundscape exposure will demonstrate superior analgesic efficacy compared to attention-placebo control.
PH1.2. Natural soundscape exposure will demonstrate superior analgesic efficacy compared to broadband sound exposure.
PH1.3. The analgesic effects of urban soundscape exposure will not significantly differ from attention-placebo control.
PH1.4. The analgesic effects of urban soundscape exposure will not significantly differ from broadband sound exposure.
PH1.5. Natural soundscape exposure will demonstrate superior analgesic efficacy compared to urban soundscape exposure.
The secondary hypotheses are:
SH1. Exposure to natural soundscapes will lead to significant pre-post improvements in both clinical outcomes and experimental indices of pain processing.
SH2. Exposure to urban soundscapes will demonstrate non-significant pre-post effects in both clinical outcomes and experimental indices of pain processing.
The study design optimizes statistical efficiency by allowing within-subject comparisons while controlling for period effects. The auditory exposure sessions are conducted in a controlled laboratory environment, maintaining a consistent room temperature and relative humidity.
To recruit participants, voluntary response, convenience, and snowball sampling methods will be employed. An a priori power analysis was conducted using G*Power v3.1.9.7. The sample size estimation is based on a Cohen's f effect size of 0.516, derived from the previous findings on the effect of nature sounds on pain in patients with chronic pain. A minimum of 58 participants is required to provide a power of 90% to adequately detect the determined pre-post difference at a two-tailed alpha level of .05. Allowing for an anticipated attrition rate of approximately one-third-including potential dropout, loss to follow-up, clinical reasons, and operational issues-a total of 88 participants will be recruited.
The assessment protocol follows International Association for the Study of Pain consensus guidelines and incorporates core outcome domains recommended for chronic pain trials. It covers both clinical outcomes (pain intensity and perceived improvement) and experimental indices of pain processing (quantitative sensory testing measures). These measures collectively provide a comprehensive evaluation of both subjective pain experience and biomarkers of pain processing, performed by a trained evaluator.
The primary analytical strategy will use linear mixed-effects models to examine change-from-baseline scores across conditions. Fixed effects will include treatment, period, sequence, and their interaction to detect potential carryover effects, while participants will be modeled with random intercepts. In the absence of carryover, a simplified model excluding the interaction term will be applied. Between-condition effects will be assessed via estimated marginal means with Bonferroni-adjusted pairwise comparisons. Sensitivity analyses will introduce the covariates to examine their influence on treatment effects. Within-condition (pre-post) changes will be evaluated using paired t-tests or Wilcoxon signed-rank tests, depending on data distribution.
To meet statistical assumptions, distributions of quantitative sensory testing outcomes-including mechanical pain sensitivity, temporal summation of pain, and pressure pain detection thresholds and intensity ratings-will be log-transformed, consistent with established methods. A small constant will be added to variables with potential zero values prior to transformation. For presentation purposes, transformed values will be back-converted to original units in descriptive outputs. All hypothesis testing will be two-sided with a Type I error rate of 5%, and analyses will follow the intention-to-treat principle. Multiple imputation will be considered if missingness is not at random.
This study is considered as minimal risk. No serious adverse events are expected. All participants may withdraw at any time without justification or impact on healthcare access. Discontinuation may occur at participants' request or in response to adverse events or protocol violations. Adverse events will be monitored throughout. Given the low-risk profile, oversight will be managed by the principal investigator; no independent safety board is planned. Safety monitoring will involve systematic documentation of all treatment-emergent and spontaneously reported adverse events throughout the study period.
To our knowledge, this study would represent one of the first investigations conceptualizing everyday soundscapes as environmental determinants potentially capable of modulating pain processing in chronic pain populations. The findings may contribute to several domains:
- Theoretical advancement in understanding auditory-pain interactions and their environmental influences.
- Development of novel, non-pharmacological auditory-based interventions for pain management in fibromyalgia syndrome.
- Informing environmental health policies and acoustic design strategies for healthcare settings.
- Contributing to the emerging field of environmental neuroscience by informing whether and how environmental sounds influence chronic pain processing.
Study design
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Crossover
- Masking
- Triple blind (care provider, investigator, outcomes assessor)
- Number of arms
- 4
- Model description
- This study employs a randomized, triple-blind, placebo-controlled crossover design based on a 4×4 Williams Latin square. Each participant receives all four interventions in a randomized, balanced sequence across four periods, with one-week washout intervals separating each session to mitigate residual effects. The design ensures equal representation of each condition across periods and sequences (uniform within sequences and periods), controlling for first-order carryover effects. This model supports within-subject comparisons, minimizes interindividual variability and confounding, and improves statistical power and internal validity using robust outcome analysis via mixed-effects modeling.
| Arm | Type | Receives |
|---|---|---|
| Sequence NBPU | Other | Other: Natural soundscape exposure, Other: Urban soundscape exposure, Other: Broadband sound exposure, Other: Blank tape attention placebo controlParticipants assigned to this sequence receive natural soundscape exposure in Week 1, broadband sound exposure in Week 2, placebo control (blank tape) in Week 3, and urban soundscape exposure in Week 4. Each session lasts 20 minutes, with one-week washout intervals between sessions. |
| Sequence UPBN | Other | Other: Natural soundscape exposure, Other: Urban soundscape exposure, Other: Broadband sound exposure, Other: Blank tape attention placebo controlParticipants assigned to this sequence receive urban soundscape exposure in Week 1, placebo control (blank tape) in Week 2, broadband sound exposure in Week 3, and natural soundscape exposure in Week 4. Each session lasts 20 minutes, with one week washout intervals between sessions. |
| Sequence BUNP | Other | Other: Natural soundscape exposure, Other: Urban soundscape exposure, Other: Broadband sound exposure, Other: Blank tape attention placebo controlParticipants assigned to this sequence receive broadband sound exposure in Week 1, urban soundscape exposure in Week 2, natural soundscape exposure in Week 3, and placebo control (blank tape) in Week 4. Each session lasts 20 minutes, with one week washout intervals between sessions. |
| Sequence PNUB | Other | Other: Natural soundscape exposure, Other: Urban soundscape exposure, Other: Broadband sound exposure, Other: Blank tape attention placebo controlParticipants assigned to this sequence receive placebo control (blank tape) in Week 1, natural soundscape exposure in Week 2, urban soundscape exposure in Week 3, and broadband sound exposure in Week 4. Each session lasts 20 minutes, with one week washout intervals between sessions. |
Who may qualify
- Ages
- 18 years and older
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (5 listed)
- A diagnosis of fibromyalgia syndrome, documented in the medical record provided by the participant prior to enrollment.
- Moderate or greater pain intensity during the preceding week, defined as a score higher than 3 on an 11-point Numeric Rating Scale.
- Normal hearing confirmed by a hearing test, defined as a mean threshold of ≤ 20 dB HL at 0.125, 0.25, 0.5, 1, 2, 4, 6, and 8 kHz.
- Ability to communicate in Spanish.
- Provision of signed written informed consent to participate in the research.
Key exclusion criteria (10 listed)
- A diagnosis of misophonia or auditory processing disorders, as documented in the participant's medical record.
- Concurrent neuropathic or acute pain.
- Severe cognitive impairment, defined as a Mini-Mental State Examination score ≤ 17.
- Severe psychiatric disorders in the symptomatic phase.
- History of substance abuse in the past 12 months or current substance use disorder as reported by the participant.
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Natural soundscape exposureAlso: Experimental intervention NParticipants receive a standardized 20-minute auditory exposure to curated natural soundscapes via high-fidelity open-back reference headphones powered by a DAC/amplifier and corrected for frequency response using calibration software. Participants are randomly assigned one of 22 recordings. Each includes 10-second fade-in/out effects and is calibrated to 45-55 dB. The stereo recordings (320-kbps MP3, 48 kHz/24-bit) feature biophony (e.g., bird vocalizations) and geophony (e.g., rainfall), free of urban sounds and selected for ecological validity based on predefined criteria: (i) recognizable/context-specific sounds; (ii) culturally neutral; (iii) foreground presence and depth; (iv) no prolonged silence; (v) no technical artifacts. During exposure, they lie supine in a 60° Fowler's position on a therapy table, with sensory input minimized through auditory isolation and controlled ambient conditions. The session involves active listening under continuous researcher supervision. | Other | Sequence BUNP, Sequence NBPU, Sequence PNUB, Sequence UPBN |
| Urban soundscape exposureAlso: Experimental intervention UParticipants receive a standardized 20-minute auditory exposure to curated urban soundscapes, using the same equipment and technical specifications as all other intervention conditions. Each participant is randomly assigned one of 22 recordings, calibrated to 60-70 dB (Leq,20min). The recordings feature anthropophony (e.g., unintelligible background speech) and technophony (e.g., transportation-related sounds), free of natural sounds and selected for ecological validity based on the same predefined criteria as the natural soundscapes. To prevent semantic processing, participants are pre-screened and post-session reconfirmed to ensure they do not understand the languages used. During exposure, participants lie supine in a 60° Fowler's position on a therapy table, with sensory input minimized through auditory isolation and controlled ambient conditions. The session involves active listening and is conducted under continuous researcher supervision. | Other | Sequence BUNP, Sequence NBPU, Sequence PNUB, Sequence UPBN |
| Broadband sound exposureAlso: Active comparatorParticipants receive a standardized 20-minute auditory exposure to broadband sounds (i.e., white or pink noise), using the same equipment and technical specifications as all other intervention conditions. Each participant is randomly assigned to one of the two noise types, with equal distribution across conditions. The stimuli are generated using professional audio software and calibrated to 50 dB (Leq,20min). During exposure, participants lie supine in a 60° Fowler's position on a therapy table, with sensory input minimized through auditory isolation and controlled ambient conditions. The session involves active listening and is conducted under continuous researcher supervision. | Other | Sequence BUNP, Sequence NBPU, Sequence PNUB, Sequence UPBN |
| Blank tape attention placebo controlAlso: Placebo comparatorParticipants receive a standardized 20-minute exposure to blank audio (silence), using the same equipment and technical specifications as all other intervention conditions. At study onset, participants are informed they will hear a range of environmental sounds, including some that may be inaudible (i.e., present but beyond the range of human hearing). During the placebo condition, a blank recording is played, producing silence, while participants remain unaware of whether they are receiving an active or placebo stimulus. This attention-control condition ensures procedural consistency while delivering no auditory stimulation. During exposure, participants lie supine in a 60° Fowler's position on a therapy table, with sensory input minimized through auditory isolation and controlled ambient conditions. The session involves active listening and is conducted under continuous researcher supervision. | Other | Sequence BUNP, Sequence NBPU, Sequence PNUB, Sequence UPBN |
Primary outcome
Pain intensity
Time frame: Change from immediately before to immediately after each 20-minute intervention session during each of the four crossover periods
The primary outcome measure assesses acute changes in subjective pain intensity following each auditory intervention. Participants mark their current pain level on a 100-mm Visual Analog Scale anchored from "no pain" to "the worst pain imaginable". The scale is scored as the distance in millimeters from the left end, with lower scores corresponding to lower perceived pain.
4 secondary outcomes
Patient global impression of change
Time frame: Assessed immediately after each 20-minute intervention session during each of the four crossover periods
Mechanical pain sensitivity
Time frame: Change from immediately before to immediately after each 20-minute intervention session during each of the four crossover periods
Temporal summation of pain
Time frame: Change from immediately before to immediately after each 20-minute intervention session during each of the four crossover periods
Pressure pain detection thresholds and intensity ratings
Time frame: Change from immediately before to immediately after each 20-minute intervention session during each of the four crossover periods
Results and safety
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 17 Nov 2025.
- Derived from this study: PubMed 42350308Gungormus DB, Perez-Marmol JM. The impact of everyday acoustic environments on chronic pain mechanisms in fibromyalgia: a randomized, triple-blind, placebo-controlled 4 x 4 crossover trial. Pain. 2026 Aug 1;167(8):1941-1957. doi: 10.1097/j.pain.0000000000004042. Epub 2026 Jun 26.
- Individual participant dataSharing planned: Yes. All individual participant data collected during the trial will be shared after de-identification, in accordance with executed data sharing agreements that require adherence to confidentiality, data protection, and non-reidentification standards equivalent to those of the originating study. The data to be shared will include baseline participant characteristics, outcome measures, covariates, and safety data. Only data necessary to replicate study findings or to conduct methodologically sound secondary analyses will be made available. The shared dataset will be accompanied by a comprehensive data dictionary that defines all variables, coding schemes, and measurement protocols to ensure full interpretation and appropriate use of the data.
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
José Manuel Pérez Mármol, PhD principal investigator
Department of Physiotherapy, Faculty of Health Sciences, University of Granada
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Natural soundscape exposure, Urban soundscape exposure and Broadband sound exposure in people with Fibromyalgia Syndrome, run by Universidad de Granada at 1 site in Spain.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 5 inclusion and 10 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: finished, as of the sponsor's last update on 17 Nov 2025. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in Spain. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Pain intensity (time frame: Change from immediately before to immediately after each 20-minute intervention session during each of the four crossover periods). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
On the ClinicalTrials.gov record for NCT07037134, which also lists 1 linked publication.
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 17 Nov 2025.