Biomedical subjects
Kathleen Bell
Publications and source records attributed to Kathleen Bell.
Access to inpatient rehabilitation after violence-related traumatic brain injury.
OBJECTIVES: To examine injury characteristics, demographics, and discharge disposition after traumatic brain injury of violent or nonviolent cause. DESIGN: Cohort study. SETTING: Level I trauma center. PARTICIPANTS: Patients (N=1807) admitted with a Head Abbreviated Injury Score (AIS) of 2 or more over a 2-year period. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Injury cause was classified as violent or nonviolent. Discharge disposition was classified as home, inpatient rehabilitation, skilled nursing facility (SNF), and other. RESULTS: The violence group was more likely to be male, to include individuals from diverse racial groups, to have an alcohol level above the legal limit, to have a more severe Head AIS, and to have Medicaid funding and equal access to inpatient rehabilitation compared with the nonviolence group. The violence group, though, was more likely to be discharged to home than to inpatient rehabilitation and more likely to be discharged to inpatient rehabilitation than to an SNF. The nonviolence group had a longer acute care length of stay and a higher rate of injuries to other body systems. CONCLUSIONS: People with violence-related injuries often present unique rehabilitation challenges. After accounting for injury severity and demographics, there was no evidence of bias against the violently injured in gaining access to inpatient rehabilitation services.
Brain function early after stroke in relation to subsequent recovery.
This study aimed to characterize brain activation and perfusion early after stroke within cortical regions that would later change activation during recovery. Patients were studied serially after stroke (mean t1, = 16 days after stroke, t2 = 3.5 months later) using perfusion-weighted imaging and functional magnetic resonance imaging during finger movement. Controls (n = 7) showed no significant change in regional activation volumes over time. Among stroke patients (n = 8), however, recovery was accompanied by several patterns of functional magnetic resonance imaging change, with increased activation volumes over time in five patients and decreased in two. Most regions increasing activation over time were in the stroke hemisphere. Of the five patients showing increased activation over time, specific activation foci enlarged at t2 were already activated at t1 in four patients, and at least one focus growing from t1 to t2 was in a different arterial distribution from the infarct in all five patients. Perfusion of sensorimotor cortex at t1 was generally not reduced in the stroke hemisphere (94% of noninfarcted hemisphere). Improved clinical outcome was related to increased activation within sensory cortices of both brain sides, including bilateral secondary somatosensory areas. Early after stroke, cortical activation that will later increase in parallel with recovery is often already identifiable, can be remote from the vascular territory of the infarct, and is not likely hindered by reduced perfusion. The findings may be useful for restorative interventions introduced during the weeks after a stroke.
Motor cortex activation is preserved in patients with chronic hemiplegic stroke.
Many central nervous system conditions that cause weakness, including many strokes, injure corticospinal tract but leave motor cortex intact. Little is known about the functional properties of surviving cortical regions in this setting, in part because many studies have used probes reliant on the corticospinal tract. We hypothesized that many features of motor cortex function would be preserved when assessed independent of the stroke-affected corticospinal tract. Functional MRI was used to study 11 patients with chronic hemiplegia after unilateral stroke that spared regions of motor cortex. Activation in stroke-affected hemisphere was evaluated using 3 probes independent of affected corticospinal tract: passive finger movement, a hand-related visuomotor stimulus, and tapping by the nonstroke index finger. The site and magnitude of cortical activation were similar when comparing the stroke hemisphere to findings in 19 control subjects. Patients activated each of 8 cortical regions with similar frequency as compared to controls, generally with a smaller activation volume. In some cases, clinical measures correlated with the size or the site of stroke hemisphere activation. The results suggest that, despite stroke producing contralateral hemiplegia, surviving regions of motor cortex actively participate in the same proprioceptive, visuomotor, and bilateral movement control processes seen in control subjects.