Swallowing
Conditions
Keywords
Motor cortex, Motor control, Neuroplasticity, Aging, Swallowing
Brief summary
The goal of this project is to examine the area of the brain that controls muscle movement for a group of muscles important for swallowing, and to see how that area changes over 2 weeks of time.
Detailed description
A large number of our nation's veterans develop dysphagia due to the myriad of potential etiological sources of swallowing disorders, including stroke and head and neck cancer. The Veteran's Health Administration has recently identified dysphagia as a major clinical focus for the VA system (Sullivan & Dennis, 2006). In order to accurately assess adaptations in motor cortex, it is first necessary to have a reliable tool for measuring organizational representation in the motor cortex. Transcranial magnetic stimulation (TMS) is a desirable choice for such measurement because of the ability to identify causative relationships between an area of motor cortex stimulated and muscle response. Therefore, the specific research objectives of this proposal are: 1. To demonstrate the reproducibility of TMS mapping of the submental muscle group in healthy older adults between 60 and 80 years of age 2. To determine the neural representation of submental musculature in the motor cortex of healthy older adults between 60 and 80 years of age. Twenty healthy adults, 10 men and 10 women, between the ages of 60 and 80 years will serve as research participants. TMS will be used to establish motor maps of the submental muscles. Subjects will undergo two testing sessions, on day 1 and day 14. The results from each session will be compared to assess excitability and representation within the motor cortex, and to assess stability and reliability of measurement.
Interventions
None listed
Sponsors
US Department of Veterans Affairs
Study design
Observational model
COHORT
Time perspective
PROSPECTIVE
Eligibility
Sex/Gender
ALL
Age
60 Years to 80 Years
Healthy volunteers
Yes
Inclusion criteria
* Between 60 and 80 years of age
Exclusion criteria
* History of dysphagia * History of neurologic disease * History of head or neck cancer * History of stroke * Untreated hypertension * History of a heart condition or heart disease * Currently pregnant * Contraindication to TMS including: * Metallic hardware on the scalp in the area where TMS will be applied * Cardiac pacemaker * Implanted medication pumps or an intracardiac line * Prior diagnosis of seizure or epilepsy in the subject (childhood history of benign febrile seizure will not be a contraindication) * Poorly controlled migraine headaches * Previous brain neurosurgery * Medications that can lower seizure threshold (Appendix B) * Unstable medical conditions * Lowest motor thresholds above 80% on TMS
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Mean Motor Evoked Potential Amplitude for Submental Cortical Representation | 2 weeks | Cortical sites are stimulated sequentially from the SOLMT in the anterior direction. At each site, 5 pulses of 110% of the MEP threshold obtained at the SOLMT are delivered and recorded. If a site produces no MEP in 3/5 pulses it is considered non-submental. This process is continued until the entire submental representation is surrounded by non-submental responsive sites. The number of sites is used to calculate the area of submental representation. The mean sEMG amplitudes of the submental muscles for each of these sites is then calculated for the mean MEP measure. |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Motor Map Center of Gravity | 2 weeks | Position on the TMS motor map with highest amplitude response to stimulation in the muscles of interest (submental muscles). |
| Area of Submental Representation | 2 weeks | Cortical sites are stimulated sequentially from the SOLMT in the anterior direction. At each site, 5 pulses of 110% of the MEP threshold obtained at the SOLMT are delivered and recorded. If a site produces no MEP in 3/5 pulses it is considered non-submental. This process is continued until the entire submental representation is surrounded by non-submental responsive sites. The number of sites is used to calculate the area of submental representation. |
Countries
United States
Participant flow
Participants by arm
| Arm | Count |
|---|---|
| Healthy Participants 20 healthy participants between 60 and 80 years of age. Ten men and 10 women. | 20 |
| Total | 20 |
Baseline characteristics
| Characteristic | Healthy Participants |
|---|---|
| Age, Categorical <=18 years | 0 Participants |
| Age, Categorical >=65 years | 16 Participants |
| Age, Categorical Between 18 and 65 years | 4 Participants |
| Age, Continuous | 68 years STANDARD_DEVIATION 6 |
| Region of Enrollment United States | 20 participants |
| Sex: Female, Male Female | 10 Participants |
| Sex: Female, Male Male | 10 Participants |
Adverse events
| Event type | EG000 affected / at risk |
|---|---|
| deaths Total, all-cause mortality | — / — |
| other Total, other adverse events | 0 / 0 |
| serious Total, serious adverse events | 0 / 20 |
Outcome results
Primary
Mean Motor Evoked Potential Amplitude for Submental Cortical Representation
Cortical sites are stimulated sequentially from the SOLMT in the anterior direction. At each site, 5 pulses of 110% of the MEP threshold obtained at the SOLMT are delivered and recorded. If a site produces no MEP in 3/5 pulses it is considered non-submental. This process is continued until the entire submental representation is surrounded by non-submental responsive sites. The number of sites is used to calculate the area of submental representation. The mean sEMG amplitudes of the submental muscles for each of these sites is then calculated for the mean MEP measure.
Time frame: 2 weeks
Population: This data was not analyzed because the study funding, as well as PIs VA affiliation, ended prior to any data analyses.
Secondary
Area of Submental Representation
Cortical sites are stimulated sequentially from the SOLMT in the anterior direction. At each site, 5 pulses of 110% of the MEP threshold obtained at the SOLMT are delivered and recorded. If a site produces no MEP in 3/5 pulses it is considered non-submental. This process is continued until the entire submental representation is surrounded by non-submental responsive sites. The number of sites is used to calculate the area of submental representation.
Time frame: 2 weeks
Population: This data was not analyzed because the study, funding, and PIs VA affiliation ended prior to any data analyses.
Secondary
Motor Map Center of Gravity
Position on the TMS motor map with highest amplitude response to stimulation in the muscles of interest (submental muscles).
Time frame: 2 weeks
Population: This data was not analyzed because the study and funding, as well as the PIs VA affiliation, ended prior to doing any analyses.