An experimental design for the control and assembly of magnetic microwheels.

Superparamagnetic colloidal particles can be reversibly assembled into wheel-like structures called microwheels (µwheels), which roll on surfaces due to friction and can be driven at user-controlled speeds and directions using rotating magnetic fields. Here, we describe the hardware and software to create and control the magnetic fields that assemble and direct µwheel motion and the optics to visualize them. Motivated by portability, adaptability, and low-cost, an extruded aluminum heat-dissipating frame incorporating open optics and audio speaker coils outfitted with high magnetic permeability cores was constructed. Open-source software was developed to define the magnitude, frequency, and orientation of the magnetic field, allowing for real-time joystick control of µwheels through two-dimensional (2D) and three-dimensional (3D) fluidic environments. With this combination of hardware and software, µwheels translate at speeds up to 50 µm/s through sample sizes up to 5 × 5 × 5 cm3 using 0.75 mT-2.5 mT magnetic fields with rotation frequencies of 5 Hz-40 Hz. Heat dissipation by aluminum coil clamps maintained sample temperatures within 3 °C of ambient temperature, a range conducive for biological applications. With this design, µwheels can be manipulated and imaged in 2D and 3D networks at length scales of micrometers to centimeters.

Trends in stroke rehabilitation.

Certain shifts and trends in stroke rehabilitation practices are occurring in the US, deriving from scientific developments, regulatory requirements, and other sources. The prevalence of stroke is increasing in the US, duration of rehabilitation hospitalizations is decreasing, and the availability of alternative methods and locations of rehabilitation services is expanding. More awareness of measures to treat medical comorbidities and the associated disabilities of stroke can be expected to enhance outcomes. New and innovative techniques, including constraint induced movement therapy, pharmacological agents, complementary or alternative medicine techniques such as acupuncture, and community activities such as exercise classes, are more widespread practices now. Novel technological interventions such as robotics and cortical stimulation are being developed to facilitate improved outcomes. The essential focus of these practices on enhancing quality of life of stroke survivors remains unaltered.

Transition to home care after stroke: depression, physical health, and adaptive processes in support persons.

A longitudinal design was used to examine adaptation in primary support persons (PSP) of stroke survivors during the transition from hospitalization (T1) to home care (T2). The major purposes of the study were (a) to examine changes in depression, physical health, and contextual and coping factors from hospitalization of the stroke survivor through the first 6-10 weeks of home care; and (b) to identify predictors of depression. Data (N = 136) were collected on depression, physical health, background, survivor illness, and social environmental variables; appraisal of impact; social support resources; and coping skills. Reduction in mean PSP depression was significant at T2, but the change in physical health was not significant. Significant changes occurred in survivor function, family functioning, and three of six coping skills. Hierarchical multiple regression analyses were used to predict depression. T1 variables accounted for 29% of the variance in T1 PSP depression, with gender and appraisal of impact the strongest of seven predictors. T1 depression, T2 health, family functioning, and avoidance coping were the strongest of seven predictors, explaining 50% of the variance in T2 depression. Findings highlight the importance of maintaining caregiver health and preventing depression and identify variables to target for the reduction of PSP depression.

A simple institutional educational intervention to decrease use of selected expensive medications.

OBJECTIVE: To determine whether a simple educational intervention can influence use of prescription medications at an institution. DESIGN: Cost-effectiveness analysis of prescribing behavior before and after an educational intervention. SETTING: A large, urban, free-standing academic rehabilitation hospital. PARTICIPANTS: Physicians, residents, and physician extenders. INTERVENTIONS: The hospital's pharmacy department provided simple written educational material about cost differences of various prescription medications to attending and resident physicians, nurse leaders, and case managers. Telephoned reminders were given when targeted medications were prescribed. MAIN OUTCOME MEASURES: Total prescription medication use was recorded monthly for 12 months before and after the intervention. Pharmaceuticals monitored were subcutaneously administered anticoagulants, histamine type 2 (H2) blockers, and nonsteroidal anti-inflammatory drugs (NSAIDs). RESULTS: A 32% decrease in use of the more costly anticoagulant and a 20% increase in use of the less costly anticoagulant (p <.0001), representing an estimated annual savings of nearly $66,000. Use of more costly H2 antagonist decreased 50% and use of less costly H2 antagonist increased 128% (p <.0001). With written intervention only, use of more costly NSAIDs declined 28%, whereas use of less costly NSAIDs increased 58% (p <.0020). CONCLUSION: Providing physicians with simple pharmaceutical cost information and telephone reminders decreased the use of targeted more costly medications.

Incidence of and risk factors for medical complications during stroke rehabilitation.

BACKGROUND AND PURPOSE: The aims of this study were to examine the frequency, types, and clinical factors associated with medical complications that occur during inpatient rehabilitation and to identify risk factors for complications that require a transfer to an acute care facility. METHODS: A cohort of 1029 patients consecutively admitted for inpatient stroke rehabilitation was studied. Demographic and stroke information, impairment, preexisting medical conditions, and admission laboratory abnormalities were recorded. Medical complications, defined as new or exacerbated medical problems, were documented for each patient. Complications that required transfer off rehabilitation were noted. Univariate and multiple logistic regression analyses were used to determine factors that were associated with risk of medical complications and risk of transfer off rehabilitation. RESULTS: Seventy-five percent of patients experienced >/=1 medical complication during rehabilitation. Significant factors for the development of any medical complication included greater neurological deficit (odds ratio [OR], 4.10; confidence interval [CI], 1.88 to 8.91), hypoalbuminemia (OR, 1.71; 95% CI, 1.15 to 2.52), and history of hypertension (OR, 1.81; 95% CI, 1.27 to 2.59). Nineteen percent of patients had a medical complication that required transfer to an acute care facility. Significant factors for transfers were elevated admission white blood cell counts (OR, 1.92; 95% CI, 1.32 to 2.79), low admission hemoglobin levels (OR, 1.89; 95% CI, 1.32 to 2.68), greater neurological deficit (OR, 2.46; 95% CI, 1.37 to 4.39), and a history of cardiac arrhythmia (OR, 1.79; 95% CI, 1.18 to 2.67). CONCLUSIONS: Medical complications are common among patients undergoing stroke rehabilitation. A significant number of these medical complications may require a transfer to an acute facility.

Comparison of sperm quantity and quality in antegrade V retrograde ejaculates obtained by vibratory penile stimulation in males with spinal cord injury.

Reduced fertility in men with spinal cord injury results from the inability to ejaculate and poor semen quality. Vibratory penile stimulation can induce ejaculation in many men with spinal cord injuries, but few studies have reported the effects of repeated vibratory stimulation on quantitative semen analysis tests. Fourteen spinal cord-injured males were enrolled in a prospective study to develop a quantitative profile of antegrade and retrograde ejaculate specimens collected during repeated vibratory stimulation. Antegrade specimens were obtained in 51 (84%) and retrograde specimens were obtained in all of the 61 trials (100%). Sperm were present in 70% and 64% of the antegrade and retrograde samples, respectively. Of the patients who underwent repeated vibratory stimulation attempts, three showed marked improvement in sperm counts and characteristics with repeated vibration and five showed normal fluctuation or no change in semen quality. Overall, there was a trend toward higher sperm counts in the antegrade samples (mean, 74.1 million) than in the retrograde samples (mean, 40 million), but no statistical significance was found. Mean sperm motility, sperm progressive motility, and percent normal sperm morphology were not significantly different between antegrade and retrograde specimens. Fructose and zinc, semen markers that reflect the presence of a true ejaculate, were present in all antegrade and retrograde specimens. In conclusion, (1) both antegrade and retrograde ejaculation occur with vibratory penile stimulation, with antegrade samples containing greater numbers of sperm but retrograde samples also having significant sperm counts, (2) repeated vibration may increase sperm concentration or may result in only minimal changes reflective of normal fluctuations, and (3) vibratory stimulation results in true ejaculation, as evidenced by semen markers.

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.