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Carrie Brown, PhD
Innovative Human Services
4636 Cherokee Trail
Dallas, TX 75209-1907
(214) 350-5350,
(214) 902-9692 (fax)

Janet Allaire, MA
Department of Pediatrics
University of Virginia Health Science Center
2270 Ivy Road
Charlottesville, VA 22901
(804) 924-8241 X 48241,
(804) 924-2780 (fax)


In an effort to combat the problem of saliva overflow (i.e., sialorrhea or drooling), Innovative Human Services, Inc., in collaboration with Children's Medical Center at the University of Virginia, and Texas Scottish Rite Hospital for Children in Dallas, have developed and tested the Chin Dry System (trademarked: only reference to trademark in this document). The Allaire research team at the University of Virginia have developed and tested the Swallow Frequency Device. These two technologies help people with the problem of saliva overflow to stay clean from unwanted saliva. The Chin Dry System vacuums unwanted saliva. The Swallow Frequency Device technology, which measures sound signals produced by swallowing by "listening", allows clinicians to know the quality and frequency of a person's swallow. The Swallow Frequency Device functions as a stand alone research unit, or works as a companion module to the Chin Dry System. The following discussion is a follow-on report of research first presented at the 1999 CSUN conference that described the prototype research development and initial testing of the Chin Dry System and Swallow Frequency Device. This presentation reports clinical testing results with both the Chin Dry System and the Swallow Frequency Device.


Problem Presentation. Drooling, (i.e., sialorrhea or saliva overflow) is the unintentional loss of saliva and other contents from the mouth (Blasco and Allaire, 1992). The topic of drooling typically generates unease, strained silences, embarrassment, or possibly jokes and amusing discussions. Drooling impacts all aspects of the quality of life in any setting for a person with this condition. Humans produce between 0.5 - 1.5 liters of saliva per day (Blasco, 1996). Lear, Flanagan and Moorrees (1965) reported this saliva is swallowed during the nearly 500 swallow occurrences adults perform in a day. Children with developmental disabilities such as Cerebral Palsy do not swallow as often as those who are able-bodied. Sochaniwskyj, Kohel, Bablich, Milner, and Kenny (1986) determined that children with cerebral palsy and saliva overflow problems swallowed at 75% of the rate of normals.

Resulting from the identified needs of the 1990 Consortium on Drooling, Ms. Jan Allaire, M.A. and her research team at the University of Virginia Health Sciences Center began development of the Swallow Frequency Device (SFD). In 1995, Carrie Brown, PhD., of Innovative Human Services, Inc., Ms. Allaire, and Dr. Richard Adams at Texas Scottish Rite Hospital for Children in Dallas, TX began collaborating to develop the Chin Dry System (CDS) technology to help control problem drooling.

The Chin Dry System (CDS) serves three functions. It keeps the user clean and dry, it collects saliva which allows for the conduct of research on saliva intervention techniques, and it can be used as a behavioral training tool to help the user to acquire better skills to control drooling. The Swallow Frequency Device (SFD) is comprised of a swallow sound transmitter and a microprocessor. It "listens" as the user swallows and can discriminate a swallow sound from a non-swallow sound.

Design and Development

Chin Dry System (CDS). The CDS technology helps people with the problem of saliva overflow (drooling) to clean themselves, or stay clean from, unwanted saliva. Saliva is vacuumed away using a collector unit that iseither hand-held, on the shirtfront, or adheres to the chin. After collecting the saliva, it is stored for measurement and disposal. The collection of the saliva allows researchers to determine if current interventions are resulting in less saliva being spilled. The CDS can monitor head position and swallowing activity (using the SFD) to give behavioral feedback to the user to remind him or her to hold their head up or to swallow.

Swallow Frequency Device. The SFD uses pattern recognition, which involves the storage of speech, swallow or other data vs. time in digital form in the computer or microprocessor. The SFD uses the principle of cervical auscultation, (listening to the sound of the person swallowing) and measures the user's frequency of swallowing. The SFD prototype is non-invasive, and constructed using a customized listening device, an analog converter, and data logger equipment. Researchers have developed a "stethophone" prototype, a combination of a stethoscope and microphone into a single unit that is placed correctly on the throat to "listen" to a swallow. The stethophone device obtains a non-invasive external sound sensor, which transmits swallow sounds but rejects other sounds such as speech and coughing as well head or muscle movements. The unit utilizes pattern recognition hardware and software, such as used in speech recognition.

Field Testing with the Chin Dry System in Dallas

Purpose. The intent of field-testing was twofold: 1) to determine if the CDS correctly detected the presence of a saliva spill and then appropriately vacuumed and stored saliva for disposal, and 2) to determine whether the user stayed drier with the CDS than without it.

The Chin Dry System. To date, researchers have had eight rounds of testing the CDS with eight research subjects who are potential users. Research subjects are students in the public schools of the Richardson, Dallas, Irving and Denton schools districts. The eight research subjects have cerebral palsy, 4 are female and 4 are male, between the ages of 7 and 18. Seven research subjects use a wheelchair and one research subject is ambulatory. Seven of the 8 research subjects are severe to profuse droolers and one is a moderate drooler. Two research subjects do not have mental retardation, two need mild support, and four research subjects need constant support.

Results. The CDS generally operated correctly. Since it is a prototype, some modifications occurred as field-testing progressed. The CDS kept the users significantly drier than they would have been without it.

Field Testing with the Swallow Frequency Device and Chin Dry System in Virginia

Purpose. Field-testing of the CDS and the SFD is ongoing. The intent of field-testing with the SFD is to determine if it interfaces properly with the CDS to monitor the swallowing activity of the research subject. Researchers in Virginia will continue to evaluate the effectiveness of the CDS as well.

Swallow Frequency Device. The SFD is designed to be an optional module that can be interfaced with the CDS. It tracks when the research subject does or does not swallow. To date, the SFD has been tested through clinical trials with people who do not have a swallowing dysfunction as well as research subjects who do have swallowing dysfunction. Testing in Virginia will be conducted with four research subjects who are residents of a state facility for people with mental retardation. Results will be reported by the time of the CSUN conference.

Literature Cited

Allaire, J., Allaire, P., and Baloh, M. (1999). Swallow frequency device: A method of swallow detection. Proceedings of the RESNA '99 Annual Conference. p. 8-10.

Blasco, P.A. (1996). "Drooling" in Feeding the Disabled Child. P.B. Sullivan & L. Rosenbloom, Eds. London: MacKeith Press.

Blasco, P. A. and Allaire, J. H. (1992). Drooling in the developmentally disabled: Management practices and recommendations. Developmental Medicine and Child Neurology, 34, p. 849-862.

Brown, C. and Allaire, J. (1999). The chin dry system and swallow frequency device: Technology for saliva overflow problems. CSUN '99 Conference Proceedings Online:

http://www.dinf.org/csun_99/session0139.html. Posted December 11, 1998.

Brown, C., and Allaire, J. (1999). Technology for the management of saliva overflow: The Chin Dry System(tm). Proceedings of the RESNA '99 Annual Conference. p. 11-13.

Lear, C.S., Flanagan, J.B., and Moorrees, C.F.A. (1965). The frequency of deglutition in man. Archives of Oral Biology, 10, 83-89.

Acknowledgement: Innovative Human Services, Inc. would like to thank the Dept. of Health and Human Services, National Institutes of Health, National Institute of Child Health and Human Development for funding this reseach. This grant is authorized under grant number 5R44HD33300-03, Technology for Swallowing Dysfunction and Sialorrhea.

Carrie Brown, PhD., Principal Investigator.

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