Clinical Trials Logo

Clinical Trial Summary

Findings in neuroscientific research show that the environment one lives in has measurable effects on brain morphology and functioning. Human exposure to airborne infra- and ultrasound has been constantly increasing during the last decades. For instance, the European Renewable Energy Directive, established in 2009, lead to an increased use of wind turbines, generating infrasound. The EU Directive states that until 2020 a 20% of the EUs' total energy needs is to be generated with renewables, therefore the current infrasound load in the European environment will increase further. Similarly, ultrasound is ubiquitous in the modern public environment, emitted from public address systems, animal repellents, industrial machines, even toothbrushes. The present study aims to investigate potential long-term effects of exposure to infra- and ultrasound on subjective well-being, cognitive and brain functioning, as well as on brain structure. The study will apply a randomized-(placebo) controlled single-blind approach to investigate this subject.


Clinical Trial Description

Regarding effects of infra- and ultrasound on the brain, a pioneer study demonstrated that exposure to non-audible infrasound was associated with changes of neural activity across several brain regions, including areas involved in auditory and emotional processing, as well as autonomic control. These findings indicate that subliminal infrasound may have pathogenic effects. Research also indicates that low intensity focused ultrasound (LIFU) modulates the BOLD signal. However, the impact of ultrasound on auditory and other brain regions remains broadly unclear until today. Regarding adverse effects of low frequency noise on (mental) health and cognitive functions, preliminary evidence (summarized by two reviews) suggests mainly negative effects on sleep, stress levels (both subjective and objective; i.e. cortisol levels), headaches, fatigue, concentration, and memory. These reviews do however not explicitly address audible low frequency noise vs. non-audible infrasound.

Research on the effects of infra- and ultrasound on cognitive functioning and well-being is in the fledgling stage. The few studies published so far vary strongly in their applied methods and results. Repeatedly, the media has covered stories about individuals suffering from 'ultrasound-sickness', a condition where the affected person suffers from headache, nausea and pain. In line with these subjective accounts, a review paper suggested that ultrasound exposure can be associated with hyperthermia, nausea, headaches, tinnitus and low blood pressure, as well as with neural excitability, irritation, memory problems and difficulties with concentration and learning, suggesting adverse effects of ultrasound exposure regarding (mental) health and cognition.

Nonetheless, there are also indicators of positive effects of these types of sound; a study suggested that brief bursts of infrasound may have a positive effect on cognitive function. Also, pioneer works in the field are currently testing ultrasound therapy for Alzheimer's patients. It appears, that the effects (positive vs. negative) may be highly variable; depending upon the frequency, sound pressure levels and duration of exposure; as well as the quality of sound (mixed audible and non-audible vs. purely non-audible). Future studies need to clearly define these variables in order to be able to make clear statements about effects.

The present study will hopefully shed further light on the long-term effects of (non-audible) infra- and ultrasound regarding human brain connectivity, structure and function, related cognitive functions and overall well-being. This may also lead to a more sophisticated and fact-based debate about 'noise pollution' of modern human living-environments.

Healthy participants, who gave their written consent, will be exposed to infra- or ultrasound for 28 consecutive days during their night sleep. The sound sources produce sound that is at least 10 dB below the hearing threshold. The sources were designed to mimic exposure to infra- and ultrasound in everyday life. The construction and calibration of the sources was realized by experts of the Physical Technical Federal Institute of Germany (Physikalisch Technische Bundesanstalt; PTB), located in Braunschweig. Sound sources will be installed and gauged at the participants' bedrooms, following a standardized procedure and emit sound for 8 hours during the participants' typical sleeping time. N = 60 participants will be randomized to one out of four conditions:

1. Infrasound verum (n = 20; frequency = 6Hz, sound pressure = 85dB)

2. Infrasound placebo (n = 10)

3. Ultrasound verum (n = 20; frequency = 22.4 kHz, sound pressure = variable +/- 10 dB)

4. Ultrasound placebo (n = 10); (single blind procedure).

First, participants, age 18-40, will be screened for eligibility. In addition, a hearing assessment will be conducted to assure normal auditory ability of all participants. Before and after the sound exposure period, participants will be tested using psychological and (neuro-)cognitive test batteries and questionnaires in order to assess psychiatric and somatic symptoms, well-being and cognitive functioning (particularly tasks that also represent everyday cognitive challenges and assess executive functions); (T1, T2). Furthermore, sensitivity to sound (including to infra- and ultrasound) and current exposure to different sound sources (T1 and T2) will be assessed with questionnaires. In addition, Magnet Resonance Imaging (MRI) will be conducted in order to illuminate morphological and functional brain changes (T1 and T2). In the scanner, participants will execute a spatial n-back task. The task assesses participants' working memory and is also suited to assess stressful reactions due to permanent cognitive load - thus constituting a 'proxy' for a stressful working task in real life. During the n-back task, a dot is presented sequentially at different positions in a grid. Participants are instructed to indicate whether the currently presented dot coincides with the dot presented 3 trials before for each of the presented dots. During the 4-week exposure period through infra-/ ultrasound, participants will also fill out weekly questionnaires, assessing well-being, general health levels, psychiatric and somatic symptoms, quality of sleep, headache and overall quality of life. ;


Study Design


Related Conditions & MeSH terms


NCT number NCT03459183
Study type Interventional
Source Universitätsklinikum Hamburg-Eppendorf
Contact
Status Completed
Phase N/A
Start date May 31, 2018
Completion date December 15, 2019

See also
  Status Clinical Trial Phase
Active, not recruiting NCT05777044 - The Effect of Hatha Yoga on Mental Health N/A
Recruiting NCT04680611 - Severe Asthma, MepolizumaB and Affect: SAMBA Study
Recruiting NCT04977232 - Adjunctive Game Intervention for Anhedonia in MDD Patients N/A
Recruiting NCT04043052 - Mobile Technologies and Post-stroke Depression N/A
Completed NCT04512768 - Treating Comorbid Insomnia in Transdiagnostic Internet-Delivered Cognitive Behaviour Therapy N/A
Recruiting NCT03207828 - Testing Interventions for Patients With Fibromyalgia and Depression N/A
Completed NCT04617015 - Defining and Treating Depression-related Asthma Early Phase 1
Recruiting NCT06011681 - The Rapid Diagnosis of MCI and Depression in Patients Ages 60 and Over
Completed NCT04476446 - An Expanded Access Protocol for Esketamine Treatment in Participants With Treatment Resistant Depression (TRD) Who do Not Have Other Treatment Alternatives Phase 3
Recruiting NCT02783430 - Evaluation of the Initial Prescription of Ketamine and Milnacipran in Depression in Patients With a Progressive Disease Phase 2/Phase 3
Recruiting NCT05563805 - Exploring Virtual Reality Adventure Training Exergaming N/A
Completed NCT04598165 - Mobile WACh NEO: Mobile Solutions for Neonatal Health and Maternal Support N/A
Completed NCT03457714 - Guided Internet Delivered Cognitive-Behaviour Therapy for Persons With Spinal Cord Injury: A Feasibility Trial
Recruiting NCT05956912 - Implementing Group Metacognitive Therapy in Cardiac Rehabilitation Services (PATHWAY-Beacons)
Completed NCT05588622 - Meru Health Program for Cancer Patients With Depression and Anxiety N/A
Recruiting NCT05234476 - Behavioral Activation Plus Savoring for University Students N/A
Active, not recruiting NCT05006976 - A Naturalistic Trial of Nudging Clinicians in the Norwegian Sickness Absence Clinic. The NSAC Nudge Study N/A
Enrolling by invitation NCT03276585 - Night in Japan Home Sleep Monitoring Study
Terminated NCT03275571 - HIV, Computerized Depression Therapy & Cognition N/A
Completed NCT03167372 - Pilot Comparison of N-of-1 Trials of Light Therapy N/A