Recovery of Paretic Lower Extremity Loading and Weight
Transfer Abilities in Individuals Who Are Post-Stroke |
|
Vicki Stemmons Mercer,
PT, Ph.D., James Cavanaugh, PT, NCS, Karen McCulloch, MS, PT, NCS, Michael Lee, M.D. |
| Stroke is a
leading cause of serious, long-term disability in the United States. About 4,400,000
stroke survivors are alive today, the majority of whom are older adults. Data from the
Framingham Heart Study indicate that 72% of the people who have a stroke in a given year
are over 65 years of age. Stroke also is one of the most expensive medical conditions in
the United States. Postacute rehabilitation services for patients who have had a stroke
account for 44% of all Medicare dollars spent on inpatient rehabilitation and about half
of all inpatient rehabilitation charges financed by Medicare. Seventy-three percent of
patients who have had a stroke receive some form of postacute rehabilitation care. |
| Individuals
with hemiparesis following a stroke often have difficulty accepting and bearing weight on
the paretic (weak) lower extremity. As a result, these individuals commonly exhibit
asymmetry in standing and during ambulation, with a greater proportion of body weight
distributed on the nonparetic limb than on the paretic limb. Although improved ability to
transfer weight and to load the paretic lower extremity is one of the main goals of
rehabilitation training for patients with hemiparesis, no investigators have described the
time course of change in these abilities following stroke. In addition, scientific
evidence for the functional significance of weight transfer and paretic limb loading
abilities is limited. Although rehabilitation professionals often assume that lower
extremity motor impairments such as weakness are directly related to limitations in
functional abilities, the presence or strength of such relationships is largely unknown. |
| Improved
understanding of the contributions of the paretic lower extremity to performance of basic
functional tasks will enable rehabilitation professionals to make more informed decisions
with respect to intervention design, discharge planning, and program evaluation. Current
clinical measures of lower extremity impairment may not capture improved ability to use
the paretic lower extremity in functional contexts, so that paretic limb contributions to
improvements in functional task performance may be overlooked. In our project, laboratory
measures of paretic lower extremity loading and weight transfer abilities are being used
to monitor very precisely the changes in these abilities that occur during the first six
months of post-stroke recovery. This information, along with the results of analyses of
the relationships among various measures of impairment, functional limitation, and
disability, will aid clinicians in determining expected outcomes for locomotor function
and physical disability. |
| The
long-term research goals are to 1) identify a battery of clinical measures of lower
extremity motor impairment that are predictive of functional limitation and disability in
individuals recovering from stroke, and 2) use this clinical battery to examine the
effectiveness of specific practice conditions and techniques in improving paretic lower
extremity loading and weight transfer abilities. Attainment of the latter goal ultimately
will require multi-center randomized controlled trials to test the effects of practice
variables such as external vs. internal focus of attention, frequency and intensity of
practice sessions, and use of biofeedback. |
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