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Biomedical subjects

M L Aisen

Publications and source records attributed to M L Aisen.

At least 19 recordsLinked to original sources
PubMed1999

Robot training enhanced motor outcome in patients with stroke maintained over 3 years.

In an attempt to improve motor recovery of the upper limb after stroke, we added a robot (MIT-Manus) experience that provided additional goal-directed sensorimotor activity to standard rehabilitation treatments. The first trial produced a significant decrease in motor impairment in the upper limb for the treated group. In re-evaluating 12 of those 20 patients, nearly 3 years later, robot-trained patients showed further significant decreases in impairment measures of the affected limb. The groups were comparable at the start of the study.

Aged↗
PubMed1999

Quantization of continuous arm movements in humans with brain injury.

Segmentation of apparently continuous movement has been reported for over a century by human movement researchers, but the existence of primitive submovements has never been proved. In 20 patients recovering from a single cerebral vascular accident (stroke), we identified the apparent submovements that composed a continuous arm motion in an unloaded task. Kinematic analysis demonstrated a submovement speed profile that was invariant across patients with different brain lesions and provided experimental verification of the detailed shape of primitive submovements. The submovement shape was unaffected by its peak speed, and to test further the invariance of shape with speed, we analyzed movement behavior in a patient with myoclonus. This patient occasionally made involuntary shock-like arm movements, which occurred near the maximum capacity of the neuromuscular system, exhibited speed profiles that were comparable to those identified in stroke patients, and were also independent of speed.

Arm↗
PubMed1999

Overview of clinical trials with MIT-MANUS: a robot-aided neuro-rehabilitation facility.

We are applying robotics and information technology to assist, enhance, and quantify neuro-rehabilitation. Our goal is a new class of interactive, user-affectionate clinical devices designed not only for evaluating patients, but also-for delivering meaningful therapy via engaging "video games". Notably, the novel robot MIT-MANUS has been designed and programmed for clinical neurological applications, and has undergone extensive clinical trials for more than four years at Burke Rehabilitation Hospital - White Plains, NY. This paper will review results of the first clinical trial of 20 patients, which showed that: - Stroke patients treated daily with additional robot-aided therapy during acute rehabilitation had improved outcome in motor activity at hospital discharge, when compared to a control group that received only standard acute rehabilitation treatment. - This improved outcome was sustained after three years. - The neuro-recovery process continued far beyond the commonly accepted 3 months post-stroke interval.

Double-Blind Method↗
PubMed1998

Robot-aided neurorehabilitation.

Our goal is to apply robotics and automation technology to assist, enhance, quantify, and document neurorehabilitation. This paper reviews a clinical trial involving 20 stroke patients with a prototype robot-aided rehabilitation facility developed at the Massachusetts Institute of Technology, Cambridge, (MIT) and tested at Burke Rehabilitation Hospital, White Plains, NY. It also presents our approach to analyze kinematic data collected in the robot-aided assessment procedure. In particular, we present evidence 1) that robot-aided therapy does not have adverse effects, 2) that patients tolerate the procedure, and 3) that peripheral manipulation of the impaired limb may influence brain recovery. These results are based on standard clinical assessment procedures. We also present one approach using kinematic data in a robot-aided assessment procedure.

Aged↗
PubMed1997

The effect of robot-assisted therapy and rehabilitative training on motor recovery following stroke.

BACKGROUND: We used MIT-Manus, a robot designed to provide interactive, goal-directed motor activity for clinical neurologic applications. OBJECTIVE: To test whether this robotic manipulation of the impaired limb influenced motor recovery in patients with hemiplegia. METHODS: Sequential patients with a history of a single stroke and hemiplegia (N = 20) hospitalized on the same acute care rehabilitation floor were enrolled in a standard rehabilitation program supplemented by either robot-aided therapy or sham robot-aided therapy. These 2 groups were comparable in age, initial physical impairment, and time between onset of the stroke and enrollment in the trial. Patients, clinical team members, and the clinical evaluator were blinded to the treatment group assignments. Standardized assessment tools measured outcomes. RESULTS: Impairment and disability declined in both groups between hospital admission and discharge. The robot-treated group showed a greater degree of improvement in all 3 measures of motor recovery, and the change in motor status measured in the proximal upper limb musculature was significant (P = .002). No adverse events resulted from robot-assisted therapy. CONCLUSIONS: These results suggest that robotic manipulation of the impaired limb may favorably add to recovery following stroke and that robotics may provide new strategies for neurologic rehabilitation.

Adult↗
PubMed1997

A comparison of low molecular weight heparin and low dose unfractionated heparin prophylaxis in subacute myelopathy.

Deep vein thrombosis (DVT) and pulmonary embolism (PE) are common life threatening complications of acute myelopathy. Prophylaxis with low dose unfractionated heparin (LDUH) has been the standard of care. Studies suggest that low molecular weight heparin (LMWH) has superior efficacy, but advantages may be offset by higher expense. Since LMWH (enoxaparin sodium) became available, standard practice at our institution has been to treat all inpatients with myelopathy with LMWH. To examine the impact of this practice, all inpatients diagnosed with myelopathy and treated with LMWH were sequentially matched by diagnosis and compared in a retrospective review with inpatients treated with LDUH. In each group, 11 patients had traumatic injury, four had transverse myelitis, four had neoplasms and five had spinal stenosis. Characteristics of the LMWH/LDUH groups were: mean age--48.5/50.4; spinal level--cervical 13/7, thoracic 9/12, lumbar 2/5; American Spinal Injury Association impairment scale-A, 8/9; B, 2/2; C, 8/5; D, 6/8. There were five DVTs and two PEs in five patients taking LDUH; there were no cases of DVT or of PE in the LMWH group (p = 0.04, two-tailed chi-square test). Isolated DVTs occurred in two patients with traumatic injuries and in one patient with transverse myelitis; PE + DVT occurred in one patient with a primary and one patient with a metastatic tumor. All developed within 3.5 months of the onset of spinal dysfunction. One patient with a traumatic injury on ibuprofen and dexamethasone had a gastrointestinal hemorrhage while receiving LMWH. The cost of administration of LMWH was $24,499 compared with $5,700 for LDUH. The LDUH group spent a total of 57 days in an acute care facility, costing $57,000.00 and patients treated with LMWH spent nine days, costing $9,000.00. We conclude that treatment with LMWH was associated with a significant decrease in incidence of DVT/PE and an overall decline in health care costs of approximately $30,000 or approximately $1,250 per patient.

Acute Disease↗
PubMed1996

A double-blind placebo-controlled study of 3,4-diaminopyridine in amytrophic lateral sclerosis patients on a rehabilitation unit.

3,4-Diaminopyridine (DAP) enhances acetylcholine release from the nerve terminal and improves conduction in demyelinated axons. In this double-blinded placebo controlled cross over study we examined the effects of DAP combined with inpatient rehabilitation in nine patients with disabling motor weakness due to amyotrophic lateral sclerosis (ALS). A single dose of DAP or placebo was increased daily to the maximum (range: 10-80 mg) tolerated dose; after patients were assessed on the first treatment, the alternate drug was given in the same manner. Functional Independence Measurement (FIM), Ashworth, grip strength, limb strength measurements, nerve conduction studies and speech assessments were initiated 1/2 h after receiving the maximum tolerated dose of DAP or placebo. DAP was tolerated in all patients, but limited by gastrointestinal side effects in four patients. The mean peak serum level was 20.11 (S.D. = 5.11) ng/ml, occurring 1.25 (S.D. = 0.56) h after dose. A statistically significant improvement in FIM and speech assessment scores between admission and discharge occurred. However, no significant differences in clinical or electrophysiologic measures were seen between DAP and placebo treatments. This study suggests that intensive inpatient rehabilitation has a role in the management of patients with ALS, but DAP does not diminish motor impairment.

4-Aminopyridine↗
PubMed1995

3,4-diaminopyridine as a treatment for amyotrophic lateral sclerosis.

The slow potassium channel blocker 3,4-diaminopyridine (DAP) enhances acetylcholine release from the nerve terminal and improves conduction in unmyelinated nerve. In this open label pilot study, we examined the effect of DAP combined with inpatient rehabilitation in seven patients with motor weakness due to amyotrophic lateral sclerosis (ALS). A single daily 20 mg oral dose of DAP was gradually increased to the maximum tolerated dose, and serum DAP concentrations were measured. Videotaped motor examination (for subsequent "blinded" review and assignment of a quantitative motor score), Functional Independence Measure (FIM) assessment, nerve conduction studies and neuropsychological evaluations were performed on admission, 1 h after maximum DAP dose, and post-treatment. DAP was tolerated in all patients, though dose was limited by gastrointestinal side effects in five patients. The mean peak serum level was 128 (+/- 50) ng/ml, occurring 1.0 (+/- 0.50) h after dose. A modest but statistically significant (p = 0.045) peak in motor score occurred on DAP. A significant (p = 0.045) improvement from baseline in FIM performance was apparent with DAP. Nerve conduction studies showed small increases in evoked response amplitudes and conduction velocities on DAP, but they did not reach statistical significance. No cognitive or affective changes were apparent. This unblinded pilot study shows that DAP is tolerated in ALS patients, and may be associated with functional and electrophysiologic improvement.

4-Aminopyridine↗
PubMed1995

The sympathetic skin response in the shoulder-hand syndrome complicating tetraplegia.

To determine the utility of the sympathetic skin response (SSR) in studying sympathetic outflow in cervical spinal cord injury (CSCI) patients who develop features of reflex sympathetic dystrophy, we studied seven consecutive CSCI patients with the shoulder-hand syndrome (SHS), and seven patients with similar injuries but without the manifestations of the SHS. The mean SSR amplitude was more than three times greater in patients with the SHS, a statistically significant difference. We restudied six patients with a SHS after symptoms had improved following steroid treatment: the mean amplitude fell significantly, approaching the mean for the control group. When pain was asymmetric, the SSR amplitude was higher in the arm with greater pain. Four of the seven SHS patients demonstrated an unusual pattern of spontaneous cyclical electrical activity during a period of severe pain. We conclude that a SHS complicating CSCI is associated with increased amplitude of the SSR, supporting the theory that sympathetic hyperactivity is important in the pathophysiology of reflex sympathetic dystrophy in this setting.

Adolescent↗
PubMed1995

Design of a controlled-energy-dissipation orthosis (CEDO) for functional suppression of intention tremors.

Conventional neurological practice is generally not successful in restoring independent upper extremity function to people with disabiling tremors. The authors have been investigating an orthotic approach, the application of energy-dissipating loads to affected limbs, to allow voluntary intent to be expressed while attenuating tremor. CEDO 1 is a prototype Controlled-Energy-Dissipation Orthosis, which permits the 3 degrees of freedom (dof) needed for table-top activities. It mounts to the user's chair or table and applies velocity-proportional resistance to his/her forearm by means of computer-controlled magnetic particle brakes. The design incorporates a stiff linkage transmission to the elbow brake of the orthosis, allowing it to be fixed in the frame of reference. This eliminates its inertia from the moving linkage and provides virtually direct drive in all 3 dof. Initial experimental results show selective clinically significant tremor reduction during experimental tracking tasks.

Algorithms↗
PubMed1994

Shoulder-hand syndrome in cervical spinal cord injury.

To characterize the occurrence of shoulder-hand syndrome (SHS) complicating the rehabilitation of patients with cervical spinal cord injury, we reviewed the medical records of 43 consecutive patients admitted to the Burke Rehabilitation Center with cervical spinal cord injury, focusing on the clinical features of SHS: shoulder pain, hand/wrist pain, edema, vasomotor changes, trophic changes and osteoporosis on x-ray. Twenty-seven patients (63%) had three or more features of SHS. The number of features correlated with age (r = 0.495, p = 0.0007), but not with the presence of upper or lower motor neuron findings in the arms, or with autonomic dysfunction. Twenty-three of 25 (92%) SHS patients with adequate follow up had satisfactory resolution of symptoms with conservative therapy (i.e. neither systemic corticosteroids nor stellate ganglion block), but only after a mean of 121 days (range 42-274 days).

Adolescent↗
PubMed1994

Falls on a neurorehabilitation unit: reassessment of a prevention program.

We conducted a retrospective case-control study of falls over a four year period on a 30 bed neurorehabilitation unit at the Burke Rehabilitation Hospital to characterize the nature of falls and identify factors associated with falling. The most common diagnoses treated on the unit were traumatic spinal cord injury, brain injury, and multiple sclerosis; stroke patients are treated on another service. Falls represented 72 percent of all incident reports made to the Nursing Office during the study period. One hundred seventeen (117) falls occurred in 82 patients during a time when the unit census was 28,622 patient days, yielding a rate of 1,439 falls per 1,000 patient years. One hundred fourteen (114) patients admitted with no history of falling during the same period were selected randomly for comparison. Most falls were associated with no injury (n = 96) or minor injury (n = 18). The most significant injuries occurred in three cases with lacerations requiring sutures. Falls occurred with greatest frequency during the first and fourth quartiles of the hospital stay, during the evening and while bed transfers were being performed. No association between falling and patient age, sex, diagnosis, number of medications, use of sedating medications, presence of motor, visual or cognitive impairment or orthostatic hypotension was evident. An increased risk of falling was associated with physician orders for Posey restraints. The implication of these findings for falls prevention programs is discussed.

Accidental Falls↗
PubMed1994

Baclofen toxicity in a patient with subclinical renal insufficiency.

Baclofen, a centrally acting gamma-aminobutyric acid agonist is a commonly used pharmacotherapy for spasticity of spinal origin. It is primarily excreted by glomerular filtration with a clearance proportional to creatinine clearance. We describe a 39-year-old quadriplegic women who, over a 16-week period, developed clinical signs of baclofen toxicity confirmed by progressively rising serum baclofen levels while on a conventional stable dosing regimen. During this period blood urea nitrogen and creatinine concentrations were normal and stable (9mg/dL and 0.8mg/dL, respectively). However, creatinine clearance values were consistently low (55 to 60m/min), suggesting renal insufficiency as the underlying cause. After a decrease in baclofen dosage, evidence of baclofen toxicity resolved. Clinicians should be alert to signs of evolving baclofen toxicity even in patients on an apparently stable regimen. Baclofen dosage adjustments based on systemic baclofen level may play a role in optimizing the clinical management of spasticity.

Adult↗
PubMed1993

Pulmonary embolism presenting as fever in spinal cord injury patients: report of two cases and review of the literature.

Pulmonary embolism is a common, sometimes fatal complication of spinal cord injury. We describe two quadriplegic patients who developed unexplained fever as the sole presenting sign of multiple pulmonary emboli during the subacute phase following injury. These cases and a review of the literature suggest that ventilation-perfusion scanning should be considered in the diagnostic evaluation of fever in patients with recent spinal cord injury even in the absence of other clinical signs of thromboembolic disease.

Adult↗
PubMed1993

The effect of mechanical damping loads on disabling action tremor.

Patients with severe action tremor have uncontrollable, relatively rapid oscillatory motion super-imposed on otherwise useable slower voluntary motor activity. Because a mechanical damper produces an opposing force proportional to velocity, applying damping loads to tremorous limbs should attenuate the (high-velocity) tremor component of movement while permitting the slower purposeful portion to proceed relatively unopposed. In this study, the effect of upper extremity damping in three degrees of freedom was examined in 10 patients with cerebellar action tremor due to multiple sclerosis or traumatic brain injury. Variable amounts of damping were applied by prototype energy-dissipating orthoses which generated resistive viscous loads by means of computer-controlled magnetic particle brakes. All patients experienced statistically and functionally significant tremor reduction with the application of damping.

Adult↗