Stroke rehabilitation: clinical predictors of resource utilization

OBJECTIVE

To identify predictors of rehabilitation hospital resource utilization for patients with stroke, using demographic, medical, and functional information available on admission.

DESIGN

Statistical analysis of data prospectively collected from stroke rehabilitation patients.

SETTING

Large, urban, academic freestanding rehabilitation facility.

PARTICIPANTS

A total of 945 stroke patients consecutively admitted for acute inpatient rehabilitation.

MAIN OUTCOME MEASURES

Resource utilization was measured by rehabilitation length of stay (LOS) and mean hospital charge per day (CPD).

METHODS

Independent variables were organized into categories derived from four consecutive phases of clinical assessment: (1) patient referral information, (2) acute hospital record review and patient history, (3) physical examination, and (4) functional assessment. Predictors for LOS and CPD were identified separately using four stepwise multiple linear regression analyses starting with variables from the first category and adding new category data for each subsequent analysis.

RESULTS

Severe neurologic impairment, as measured by Rasch-converted NIH stroke scale and lower Rasch-converted motor measure of the Functional Independence Measure (FIM) instrument predicted longer LOS (F2,824 = 231.9, p < .001). Lower Rasch-converted motor FIM instrument measure, tracheostomy, feeding tube, and a history of pneumonia, coronary artery disease, or renal failure predicted higher CPD (F6,820 = 90.2, p < .001).

CONCLUSION

Stroke rehabilitation LOS and CPD are predicted by different factors. Severe impairment and motor disability are the main predictors of longer LOS; motor disability and medical comorbidities predict higher CPD. These findings will help clinicians anticipate resource needs of stroke rehabilitation patients using medical history, physical examination, and functional assessment.

Impairment and disability: their relation during stroke rehabilitation

OBJECTIVES

To describe the association between impairment and disability during stroke rehabilitation and to examine the effects of rehabilitation by studying the degree of disability reduction experienced by stroke patients who did not have significant reductions in impairment levels.

DESIGN

Statistical analysis of items from a database of prospectively collected information on stroke patients admitted for rehabilitation.

SETTING

Large urban academic freestanding rehabilitation facility.

PARTICIPANTS

Four hundred two patients consecutively admitted for comprehensive acute stroke inpatient rehabilitation.

MAIN OUTCOME MEASURES

The National Institutes of Health Stroke Scale (NIHSS) was used to measure impairment and the Functional Independence Measure (FIM) was used to measure disability. Motor and cognitive subscales of the FIM instrument were evaluated. Raw NIHSS and FIM scores were converted to linear measures using Rasch analysis.

METHODS

Relationships were studied between converted NIHSS and the two FIM subscales for admission, discharge, and change scores using linear regression analysis. In a second analysis, two groups of patients were identified; the 342 patients who experienced no substantial reduction of impairment comprised the "no impairment reduction (NIR) group," and the 60 patients who had a significant reduction of impairment level comprised the "impairment reduction (IR) group." Multivariate analysis of variance was used to determine and compare the amount of change in motor and cognitive FIM measures over time for each of the two groups.

RESULTS

NIHSS correlated significantly with motor and cognitive FIM subscores for admission, discharge, and change measures; R2 values ranged between .02 and .36. Both the NIR group and the IR group experienced significant decreases in disability during rehabilitation. The differences in discharge FIM measures between the two groups were relatively small.

CONCLUSIONS

Although stroke-related impairment and disability are significantly correlated with each other, reduced impairment level alone does not fully explain the reduced disability that occurs during rehabilitation. Even patients without substantial impairment reduction demonstrate disability reduction during rehabilitation, suggesting that rehabilitation has an independent role in improving function beyond that explained by neurologic recovery alone.

Cardiovascular disease in patients with dysvascular amputation

Cardiovascular diseases are the most common causes of morbidity and mortality in individuals with peripheral vascular disease (PVD). Among patients who have undergone lower extremity amputation as a result of PVD, the prevalence of concomitant cardiovascular disease may be as high as 75%. Comorbid heart disease may complicate the postamputation course of recovery, delay initiation of rehabilitation training, and inhibit the achievement of maximal functional independence. A variety of methods have been used to assess cardiac status and risk in amputation patients undergoing physical training; these have included clinical evaluation, resting electrocardiography, and continuous dynamic electrocardiography during either standard physical therapy exercise or adapted ergometry. Several conditioning training programs have been developed to improve the cardiovascular fitness of patients with dysvascular amputation, the results of which have been favorable. These assessment and intervention strategies have extensive applicability in the clinical management of patients with dysvascular amputation.

Ventilatory function in cervical and high thoracic spinal cord injury. Relationship to level of injury and tone

Weakness and spasticity of chest wall muscles are known to adversely affect pulmonary function in spinal cord-injured patients. To test the assertion that impaired strength and increased tone contribute to ventilation deficits, 52 patients with recent acute traumatic cervical and high thoracic spinal cord injury underwent complete pulmonary function testing. Regression analyses were performed to determine relationships between spinal cord injury level and pulmonary function test results and between Ashworth scale tone ratings and pulmonary function test results. Level of injury was found to be significantly correlated with expiratory reserve volume (and percent predicted expiratory reserve volume), residual volume/total lung capacity ratio, and negative inspiratory pressure but not with vital capacity, forced expiratory volume in one second, forced expiratory volume in one second/vital capacity ratio, inspiratory capacity, total lung capacity, functional residual capacity, residual volume, or positive expiratory pressure. There were significant correlations between Ashworth Scale tone ratings and negative inspiratory pressure but not between tone ratings and any of the other pulmonary function test results. It appears that muscle strength may be a more important factor than muscle tone in determining pulmonary function in spinal cord-injured patients and that both strength and tone are closely related to negative inspiratory pressure.

Measurement properties of the NIH Stroke Scale during acute rehabilitation

BACKGROUND AND PURPOSE

The scale of stroke impairment characteristics by Brott and associates, the National Institutes of Health (NIH) Stroke Scale, has been used widely in various studies of stroke outcome; however, the measurement properties of the items applied to patients during medical rehabilitation have not been evaluated thoroughly. This study evaluated the extent to which scale items cohere to define a unidimensional construct and have a useful range for application to patients during medical rehabilitation.

METHODS

Rating scale (or Rasch) analysis of the 15 NIH Stroke Scale items was conducted using the BIGSTEPS computer program to evaluate (1) the range of impairment assessed by the items, (2) the items' coherence with an underlying construct of impairment, and (3) range of impairment measured in rehabilitation patients. We sought to maximize the range of impairment measured by conducting analyses recursively; at each subsequent step, the worst fitting item was deleted or rescored. The sample comprised 1291 admission and discharge records from 693 rehabilitation inpatients with stroke.

RESULTS

Thirteen items arrayed the sample across a sufficient range of impairment. The limb ataxia item fit poorly and was deleted; lower ratings for this item were associated with higher scores on the total scale. Pupillary response was also deleted because ratings reflected poor congruence with the total score. Best language was rescored because intermediate ratings were inconsistently related to the total score. Patients with hemorrhagic strokes had poorer fitting measures than did patients with ischemic strokes.

CONCLUSIONS

The items in a revised NIH Stroke Scale worked well together to define the severity of impairment resulting from stroke that is observed during medical rehabilitation. Directions regarding limb ataxia should be modified to indicate untestability due to hemiplegia.

Reversion to a previously learned foreign accent after stroke

Foreign accent syndrome occurs rarely after stroke. Most patients with this syndrome develop an aphasia characterized by a new accent. This report presents a 48-year-old man who sustained a left parietal hemorrhagic stroke resulting in right hemiparesis and the inability to speak. As spontaneous speech emerged several weeks later, he was noted to have a Broca's aphasia and a Dutch accent. Analysis of his speech demonstrated final consonant deletion, substitution of "d" for "th" sounds, vowel distortions, additional "uh" syllables added at the end of words, and errors in voicing. This speech pattern has persisted for more than 5 years after the stroke. Elicitation of additional history found that the patient was born in Holland and lived there until the age of 5 years, when he moved to the United States with his family. Before his stroke, he had no foreign accent. This report illustrates the importance of considering foreign accent syndrome during aphasia recovery and suggests several pathogenetic mechanisms that may contribute to the development of this syndrome.

Hemiplegic gait. Relationships between walking speed and other temporal parameters

It has been asserted that speed alone is an effective indicator of the degree of gait abnormality. To determine the validity of this assertion, relationships between velocity and 18 other temporal gait parameters were determined in 25 patients with a first hemispheric stroke resulting in hemiplegia or hemiparesis of at least one month duration. Gait characteristics were recorded using footswitchs connected to a portable computerized monitoring device. Velocity was found to be significantly correlated with cadence, mean cycle duration, mean cycle length, hemiplegic limb stance phase duration, nonhemiplegic limb stance phase duration and percent, nonhemiplegic limb swing phase percent, double support phase duration and percent, hemiplegic limb swing/stance phase ratio, nonhemiplegic limb swing/stance phase ratio, and swing phase symmetry ratio but not with the hemiplegic limb stance phase percent, hemiplegic limb swing phase duration and percent, nonhemiplegic limb swing phase duration, stance phase symmetry ratio, and overall asymmetry ratio. Velocity is related to most, but not all, of the other temporal measures of hemiplegic gait. A comprehensive gait evaluation should also include characterization of the degree of asymmetry and descriptions of individual phase durations and proportions (particularly hemiplegic stance and swing percentages).

Deep vein thrombosis in stroke. The use of plasma D-dimer level as a screening test in the rehabilitation setting

BACKGROUND AND PURPOSE

Venous thromboembolism is a leading cause of morbidity and mortality during the acute recovery period after stroke. This study investigated the utility of plasma D-dimer level as a diagnostic test for deep vein thrombosis (DVT) in patients hospitalized for stroke rehabilitation.

METHOD

Plasma samples were drawn from 105 nonambulatory rehabilitation patients with recent ischemic or hemorrhagic stroke and assayed for D-dimer with an enzyme-linked immunosorbent method. Samples were drawn within 24 hours of venous duplex ultrasound (VDU) screening for DVT. Optimal discriminant analysis was used to determine whether plasma D-dimer level, age, sex, days after stroke onset, stroke etiology. National Institutes of Health Stroke Scale score, and ambulatory status could correctly classify patients' DVT status.

RESULTS

Fourteen of 105 patients had DVT identified by VDU scan. Of all attributes, only D-dimer level had significant ability to discriminate between patients with or without DVT (P < .0001). The optimal cut point for predicting DVT was D-dimer = 1591 ng/mL, resulting in 79% sensitivity, 78% specificity, 35% positive predictive value, and 96% negative predictive value. Reducing the D-dimer cut point to 1092 ng/mL improved both sensitivity and negative predictive value to 100% but reduced specificity to 66% and positive predictive value to 31%.

CONCLUSIONS

A D-dimer level < or = 1092 ng/mL can exclude the presence of DVT in stroke rehabilitation patients. When a D-dimer level > 1092 ng/mL occurs, further diagnostic testing is necessary to confirm DVT. Plasma D-dimer level is a simple and inexpensive screening test for DVT during stroke rehabilitation.

An integrated physical and genetic map of a 35 Mb region on chromosome Xp22.3-Xp21.3

We have constructed a detailed physical map of the 35 Mb region spanning human chromosome Xp22.3-Xp21.3. The backbone of the map is represented by a single oriented contiguous stretch of 585 overlapping yeast artificial chromosome (YAC) clones covering the entire region. The map is formatted with 615 map objects that include 324 YACs, 185 sequence tagged sites, 28 genes, 85 chromosomal breakpoints and 37 highly polymorphic markers. Physical mapping was both guided and confirmed using 183 bins defined by chromosomal breakpoints and by overlapping regions of YAC clones. The localization of polymorphic markers in the physical map permits the integration of physical and genetic data across the region. These data establish chromosome Xp22.3-Xp21.3 as one of the best characterized large regions in the human genome. The map should greatly facilitate finer scale mapping and sequencing as well as the identification of disease genes from this portion of the human genome.

Pulmonary function testing in spinal cord injury: correlation with vital capacity

Spinal cord injury (SCI) causes restrictive ventilatory changes, with reductions in vital capacity, functional residual capacity, and expiratory reserve volume. Vital capacity (VC) often is used as an indicator of overall pulmonary function in these patients. In an effort to determine the extent to which VC correlates with other pulmonary function tests, 52 patients with recent acute traumatic SCI underwent complete pulmonary function testing. Statistical relationships were determined between VC and nine other tests. VC was found to be significantly correlated with forced expiratory volume in 1 s, inspiratory capacity, expiratory reserve volume, functional residual capacity, residual volume (RV), total lung capacity (TLC), and RV/TLC ratio, but not with maximum positive expiratory pressure nor with maximum negative inspiratory pressure. The excellent correlations between vital capacity and nearly all of the other pulmonary function tests support the use of VC as a single global measure of overall ventilatory status in SCI patients.

Management of impotence due to spinal cord injury using low dose papaverine

Erectile dysfunction is a common complication of spinal cord injury. Of the 68 spinal cord injured men in whom treatment with papaverine was initiated a therapeutic dosage was determined in 50 (74%). Papaverine was injected into the base of one corpora cavernosum. The dose started at 3 mg and was increased at weekly or longer intervals until an effective dose was determined. There were 15 (30%) men with tetraplegia and 35 (70%) men with paraplegia. The dosage of papaverine did not relate to the level or extent of injury. Doses of 12 mg or less were used in 56% of patients. Low dose papaverine is a safe and effective means of restoring erections in spinal cord injured men.

Identification and characterization of the gene causing type 1 spinocerebellar ataxia

Spinocerebellar ataxia type 1 (SCA1) is a neurodegenerative disorder caused by expansion of a CAG trinucleotide repeat. In this study, we describe the identification and characterization of the gene harbouring this repeat. The SCA1 transcript is 10,660 bases and is transcribed from both the wild type and SCA1 alleles. The CAG repeat, coding for a polyglutamine tract, lies within the coding region. The gene spans 450 kb of genomic DNA and is organized in nine exons. The first seven fall in the 5' untranslated region and the last two contain the coding region, and a 7,277 basepairs 3' untranslated region. The first four non-coding exons undergo alternative splicing in several tissues. These features suggest that the transcriptional and translational regulation of ataxin-1, the SCA1 encoded protein, may be complex.