This study will use magnetic resonance imaging (MRI) and ultrasound to examine changes in
tongue volume and blood circulation during tongue exercises that require the use of
different tongue muscle movements and contractions. More information on the structure and
function of the human tongue is needed to develop better treatments for people with certain
diseases affecting speech and swallowing.
Normal volunteers between 21 and 80 years old who live in the metropolitan Washington, D.C.,
area may be eligible for this study. Candidates will be screened with a brief medical
history and physical examination, including suitability for MRI testing, and a brief
examination of tongue, lip and jaw movements.
Participants will undergo ultrasound and MRI studies. During both tests, they will perform
tongue exercises, such as holding a soft round object on the tongue or exerting tongue
pressure against the back of the throat or roof of the mouth.
During the ultrasound, the subject lies on a flattened dental chair. A small transducer is
placed under the chin to take images of the tongue during the exercises. A thin rubber strip
with air-filled pressure bulbs is attached to the roof of the mouth (with dental adhesive)
to measure tongue pressure.
For the MRI, the subject lies on a table that slides inside a donut's machine containing a
magnetic field. MRI coils-special padded sensors that improve image quality-are placed
around the head and neck. A pressure cuff placed around the arm measures blood pressure. The
subject wears earplugs to muffle loud thumping noises that occur during electrical switching
of the magnetic fields. The subject is in constant visual contact with the researchers and
MR technologist and may request to stop the study at any time.
Participants may undergo another procedure, called magnetic resonance diffusion tensor
imaging, to examine how the fluid (water) in the tongue tissue shifts during tongue
maneuvers. This procedure is essentially the same as the first MRI study, but two small
round coils are placed in the mouth (one on each side) between the cheeks and the teeth.
As an organ unparalleled in anatomical architecture, the tongue has the versatility to
effect regional deformations and positional changes with multiple potential degrees of
freedom. Despite an abundance of studies on the tongue and its functions, as well as
numerous proposed tongue models over the years, much of the anatomical and biomechanical
details of the in vivo human tongue remain poorly understood. Physiologically based
biomechanical modeling of the tongue in swallowing is the ultimate objective of this
protocol. However, before such modeling can be accurately pursued, a substantial database
must be established, and several important, unaddressed issues regarding lingual anatomy and
biomechanics must be resolved. These issues include: (1) the compressibility of the human
tongue and its common, yet untested, reference as a muscular hydrostat; (2) task induced
interactions between lingual musculature and vasculature and region-specific vascular
demands; (3) changes in lingual fiber orientation, length, and strain distribution as a
function of contraction tasks; and (4) effects of normal aging, disease processes, and task
training on lingual myoarchitecture as well as the integration between structure and
function. Using advanced 3D MRI, Doppler ultrasonography, and other MR imaging techniques
(e.g., tagged MRI, diffusion tensor MRI), this protocol proposes to quantitatively address
these issues and contribute to a better understanding of the functional biomechanical as
well as myoarchitectural intricacies of the in vivo human tongue.
- INCLUSION CRITERIA
1. be older than 21 years in age;
2. reside in the Metropolitan Washington, D.C. Area;
3. have no speech, swallowing, respiratory, or cardiac problems;
4. be able to hold breath for at least 20-30 seconds;
5. be in good general health;
6. not be pregnant or nursing;
7. not be on medications that would adversely affect blood pressure, circulation,
pulmonary function, speech, or swallowing ability.
1. be older than 21 years in age;
2. not be pregnant or nursing;
3. have tongue weakness, as confirmed in oral motor examination, associated with
neurologic, degenerative, musculoskeletal, or other diseases.
1. Any contraindication for MRI, including:
pacemaker or other implanted electronic device
metal in the eye
embedded shrapnel fragments
cerebral aneurysm clips
medical infusion pumps
orthodontic braces, unremovable metal retainer, dental implants, crowns, long metal
bridges, large or multiple amalgam fillings
metal clips or wires in other parts of the body
2. Medical conditions that present elevated risks or reduced tolerance for an MRI
severe and uncontrolled hypertension
severe cardiovascular disorders
dyspnea at rest
severe claudication (less than 1 flight of steps)
symptoms of pheochromocytoma or insulinoma
severe asthma, allergies and postnasal drainage
uncontrolled renal or hepatic disease
severe back pain and inability to tolerate supine positioning
pregnancy or lactation
3. History of swallowing problems or other conditions that adversely affect cardiac
function, deglutitive function, tongue motility and control, hearing, language, and
4. Unsatisfactory performance status, as judged by the examining speech-language
pathologist, that indicates poor compliance for the planned tasks (e.g., oral motor
deficits, inability to hold breath for at least 20 seconds).
1. Any contraindication for MRI, same as 5.2.1 (1);
2. Medical conditions that present high risks or severely reduced tolerance for an MRI
procedure, as determined by or based on consultation with the medically responsible
individual (or a designated substitute);
3. History of other conditions that have severely impaired cardiac function, hearing,
language, and cognition.