Standards Spotlight

A potential new treatment regimen is giving hope to people who suffer from chronic pain. Researchers from the University of Minnesota Twin Cities have found that combining electrical stimulation of the body with broadband sound activates the part of the brain that is responsible for receiving and processing pain sensations.

The non-invasive technique was tested on guinea pigs, and researchers plan to continue investigating its potential for multiple neurological conditions in humans. Ultimately, music therapy may be integrated into treatment regimens if researchers find that they can further modify the somatosensory cortex in the brain. The paper’s authors cite the technique as a promising alternative to opioids, and a non-invasive, simple, and inexpensive application that could be readily available to anyone who needs it.

Researchers used needle stimulation on the guinea pigs in their experiments, but future iterations of the procedure could use electrical stimulation devices, such as transcutaneous electrical nerve stimulation (TENS) units, which are widely available. In the U.S., TENS units are guided by a safety and performance American National Standard (ANS) developed by the Association for the Advancement of Medical Instrumentation (AAMI), a member and accredited standards developer of the American National Standards Institute (ANSI). ANSI/AAMI NS4, Transcutaneous Electrical Nerve Stimulators, establishes labeling, safety, and performance requirements and referee tests for these devices, as well as labeling requirements for patient leads and electrodes.

International standards guide nerve and muscle stimulators as well. IEC 60601-2-10, Medical Electrical Equipment – Part 2-10: Particular Requirements for the Basic Safety and Essential Performance of Nerve and Muscle Stimulators, guides both TENS units and electrical muscle stimulators (EMS), which are similar to TENS but used to strengthen and rehabilitate muscles rather than relieve pain. This standard was developed by the International Electrotechnical Commission (IEC) Technical Committee (TC) 62, Electrical equipment in medical practice, Subcommittee 62D, Electromedical equipment. AAMI is the U.S. National Committee to the IEC (USNC)-accredited Technical Advisory Group (TAG) administrator to this TC.

Acupuncture and electrical simulation have long been used to alter brain activity and treat pain, but combining it with sound may offer even more relief. The guinea pigs in this experiment listened to broadband sound – a sound that contains a large number of single frequency components, having its energy distributed over a wide section of the audible range. Standards guide, describe, and quantify information about sound that could inform the audio used in future experiments. ANSI/ASA S12.58, Sound Power Level Determination for Sources Using a Single-source Position is an ANS developed by the Acoustical Society of America (ASA) that describes a method for the determination of sound power level noise sources that emit broadband sound and/or discrete frequency sounds and tones in reverberation rooms.

Another standard, ISO 532-1, Acoustics – Methods for Calculating Loudness – Part 1: Zwicker Method, specifies two methods for estimating the loudness of sounds as perceived by otologically normal persons under specific listening conditions. This standard was developed by the International Organization for Standardization (ISO) TC 43, Acoustics. ASA, an ANSI member and accredited standards developer, is the ANSI-accredited U.S. TAG administrator to TC 43.

Learn more about the University of Minnesota Twin Cities research: Study find that sound plus electrical body stimulation has the potential to treat chronic pain.