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Biomedical subjects

Henry L Lew

Publications and source records attributed to Henry L Lew.

At least 19 recordsLinked to original sources
PubMed2006

Ultrasound-guided shoulder injections in the treatment of subacromial bursitis.

OBJECTIVE: To investigate the treatment effectiveness between ultrasound-guided and blind injection techniques in the treatment of subacromial bursitis. DESIGN: A total of 40 patients with sonographic confirmation of subacromial bursitis were recruited into this study. These patients were divided into blind and ultrasound-guided injection groups. The shoulder abduction range of motion was compared before injections and 1 wk after the completion of injections in both groups. RESULTS: The shoulder abduction range of motion before injection in the blind injection group was 71.03 +/- 12.38 degrees and improved to 100 +/- 18.18 degrees 1 wk after the injection treatments. However, the improvement did not reveal significant statistical differences (P > 0.05). The shoulder abduction range of motion before injection in the ultrasound-guided injection group was 69.05 +/- 14.72 degrees and improved to 139.29 +/- 20.14 degrees 1 wk after the injection treatments (P < 0.05). CONCLUSIONS: Ultrasound may be used as an adjuvant tool in guiding the needle accurately into the inflamed subacromial bursa. The ultrasound-guided injection technique can result in significant improvement in shoulder abduction range of motion as compared with the blind injection technique in treating patients with subacromial bursitis.

Adult↗
PubMed2006

Bone-density changes after stroke.

It has been many years since bone loss and fracture risk were first recognized as serious complications of stroke. Hip fracture is associated with a substantial increase in morbidity and mortality for stroke survivors, and therefore, assessing and maintaining skeletal health after stroke should be an important clinical goal. Recent long-term, prospective studies have illustrated a highly nonuniform pattern of bone changes after stroke. In general, there is significant bone loss on the paretic side, which is greatest in those patients with the most severe functional deficits. In some patients, bone loss in the paretic arm during the first year after stroke is the equivalent of >20 yrs of bone loss in healthy individuals of comparable age. Bone density in the nonparetic upper limb can actually increase after stroke, consistent with an increase in habitual use of the nonparetic hand. Bone density in the paretic lower limb can decrease by >10% in <1 yr, with smaller decreases being typical for the nonparetic lower limb. Despite the recent increase in the number of prospective, longitudinal studies, important questions about bone changes after stroke remain unanswered. Longer-term studies quantifying bone loss for periods of >12 mos poststroke are needed to determine how long excess bone loss continues after stroke. Studies with more subjects and with more varied disability levels are needed to better understand the relationships between functional deficits and bone loss. New metrics are needed to quantify the intensity and duration of physical activity in the upper and lower limbs that are consistent with previous research on the role of mechanical stimuli in bone adaptation. Finally, an assessment of skeletal health and the factors that affect bone quantity and quality should be a standard component in the clinical management of all survivors of stroke.

Absorptiometry, Photon↗
PubMed2006

Characteristics and treatment of headache after traumatic brain injury: a focused review.

Headache is one of the most common complaints in patients with traumatic brain injury. By definition, headache that develops within 1 wk after head trauma (or within 1 wk after regaining consciousness) is referred to as posttraumatic headache (PTH). Although most PTH resolves within 6-12 mos after injury, approximately 18-33% of PTH persists beyond 1 yr. We performed a systematic literature review on this topic and found that many patients with PTH had clinical presentations very similar to tension-type headache (37% of all PTH) and migraine (29% of all PTH). Although there is no universally accepted protocol for treating PTH, many clinicians treat PTH as if they were managing primary headache. As a result of the heterogeneity in the terminology and paucity in prospective, well-controlled studies in this field, there is a definite need for conducting double-blind, placebo-controlled treatment trials in patients with PTH.

Analgesics↗
PubMed2005

Sensitivity, specificity, and variability of nerve conduction velocity measurements in carpal tunnel syndrome.

OBJECTIVE: To explore the diagnostic values of 8 commonly used electrodiagnostic techniques for measuring median nerve conduction velocity (NCV) in carpal tunnel syndrome (CTS). DESIGN: Sensitivity and specificity analyses. SETTING: A hospital-based electrodiagnostic laboratory. PARTICIPANTS: Forty-four normal hands and 136 symptomatic hands. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: (1) Long-segment studies: antidromic wrist-to-digit sensory NCV without subtraction, (2) short-segment studies: transcarpal palm-to-wrist mixed NCV without subtraction, and (3) 2 segment studies: antidromic transcarpal sensory NCV with subtraction (differential calculation from wrist-to-digit and palm-to-digit segments). Both onset and peak latency values were obtained for calculating the NCV. Sensitivity, specificity, and coefficient of variance were calculated for each NCV study. RESULTS: The short-segment, onset latency-based transcarpal mixed NCV yielded the highest sensitivity (75%). CONCLUSIONS: Results from measurement of a single, short-nerve segment tended to be superior to results obtained by either long-segment studies or differential subtraction between 2 segments of the same nerve in the electrodiagnosis of CTS. Explanations for our results are offered from both electrophysiologic and statistical perspectives.

Adult↗
PubMed2005

Predictive validity of driving-simulator assessments following traumatic brain injury: a preliminary study.

OBJECTIVE: To evaluate whether driving simulator and road test evaluations can predict long-term driving performance, we conducted a prospective study on 11 patients with moderate to severe traumatic brain injury. Sixteen healthy subjects were also tested to provide normative values on the simulator at baseline. METHOD: At their initial evaluation (time-1), subjects' driving skills were measured during a 30-minute simulator trial using an automated 12-measure Simulator Performance Index (SPI), while a trained observer also rated their performance using a Driving Performance Inventory (DPI). In addition, patients were evaluated on the road by a certified driving evaluator. Ten months later (time-2), family members observed patients driving for at least 3 hours over 4 weeks and rated their driving performance using the DPI. RESULTS: At time-1, patients were significantly impaired on automated SPI measures of driving skill, including: speed and steering control, accidents, and vigilance to a divided-attention task. These simulator indices significantly predicted the following aspects of observed driving performance at time-2: handling of automobile controls, regulation of vehicle speed and direction, higher-order judgment and self-control, as well as a trend-level association with car accidents. Automated measures of simulator skill (SPI) were more sensitive and accurate than observational measures of simulator skill (DPI) in predicting actual driving performance. To our surprise, the road test results at time-1 showed no significant relation to driving performance at time-2. CONCLUSION: Simulator-based assessment of patients with brain injuries can provide ecologically valid measures that, in some cases, may be more sensitive than a traditional road test as predictors of long-term driving performance in the community.

Adolescent↗
PubMed2005

Intradiscal electrothermal annuloplasty.

Low back pain is a common problem, and although the majority of cases of low back pain resolve, a subset of patients will continue to have intractable pain despite appropriate conservative treatments. Intradiscal electrothermal annuloplasty is a minimally invasive spinal procedure that has been proposed to treat provocation discography-proven internal disk disruption syndrome. The early uncontrolled and nonrandomized intradiscal electrothermal annuloplasty literature suggests it may provide some relief in a small proportion of strictly defined patients; however, more recent randomized, placebo-controlled trials have not substantiated these initial findings. This article will review the published literature, indications, contraindications, safety, and efficacy of the intradiscal electrothermal annuloplasty procedure for the treatment of chronic, intractable, axial back pain.

Contraindications↗
PubMed2004

Principles and clinical applications of auditory evoked potentials in the geriatric population.

Age-related changes in auditory evoked potentials are complex and complicated by the confounding effects of gender; concomitant high-frequency hearing sensitivity loss; and, in the case of event-related responses, the nature of the task used to elicit the response. There is a tendency for amplitude to decline and latency to increase, but these trends are not always clear-cut. There is also a tendency for activation patterns to move forward from parietal to frontal areas as age increases. The dichotic listening tool has revealed age-related changes in interaural and interhemispheric asymmetries. These asymmetries seem to be related to loss in the efficiency of interhemispheric transfer via the corpus callosum.

Aged↗
PubMed2004

Overview of artifact reduction and removal in evoked potential and event-related potential recordings.

Artifact in one form or another needs to be contended with in all EEG and EP studies. Various methods have been employed to avoid, eliminate, or minimize artifact. This article has described the methods that have been available for some time and newer methods and their advantages. It is the authors' hope that through the use of these methods the accuracy of all EP and ERP measurements will be improved and promote the validity and general acceptance of EP and ERP recordings. Genuine and valuable data are contained in EPs and ERPs. The challenge is to extract relatively small voltage signals often occurring within a higher voltage background of artifact. The computing power required to perform the artifact removal/reduction procedures now is available with basic laptop and desktop computers, as are the software programs that provide the artifact removal/reduction capabilities. It may be of interest for a prudent researcher to integrate the currently available artifact rejection methods before subjecting the ERP and EP data for further analysis and subsequent publication.

Artifacts↗
PubMed2004

Overview of dipole source localization.

Truly accurate dipole source localization relies on having (1) reliable, artifact-free EP/ERP (or magnetoelectroencephalogram) data to start with; (2) landmark and electrode position data obtained with a three-dimensional digitizer; (3) MRI (or CT) data from the same subject (with a means to measure the same landmarks); (4) the capability to apply different dipole and volume conductor models; and (5) the ability to coregister the functional and anatomic data to display the final source solutions. Most important is to have a thorough understanding of the fundamental principles of the localization programs and neurophysiologic processes. Localization programs are simply tools. Used incorrectly, they can yield meaningless results. Used correctly, they can provide a window into neurophysiologic functioning that is not available through any other means.

Brain↗
PubMed2004

Complementary and alternative medicine education in the United States, China, and Taiwan.

As public demand for complementary and alternative medicine increases,it is important for physical medicine and rehabilitation physicians to have some basic understanding of complementary and alternative medicine or at least to appreciate some of the approved indications so that appropriate referrals can be made. Because the concept of evidence-based medicine is essential for a successful physical medicine and rehabilitation practice in either academic or private facilities, well-developed research projects, such as randomized, controlled trials of large sample size, are needed to investigate the efficacy and safety of complementary and alternative medicine therapy.

China↗
PubMed2004

Ultrasound guidance in caudal epidural needle placement.

BACKGROUND: This study was conducted to investigate the feasibility of using ultrasound as an image tool to locate the sacral hiatus accurately for caudal epidural injections. METHODS: Between August 2002 and July 2003, 70 patients (39 male and 31 female patients) with low back pain and sciatica were studied. Soft tissue ultrasonography was performed to locate the sacral hiatus. A 21-gauge caudal epidural needle was inserted and guided by ultrasound to the sacral hiatus and into the caudal epidural space. Proper needle placement was confirmed by fluoroscopy. RESULTS: In all the recruited patients, the sacral hiatus was located accurately by ultrasound, and the caudal epidural needle was guided successfully to the sacral hiatus and into the caudal epidural space. There was 100% accuracy in caudal epidural needle placement into the caudal epidural space under ultrasound guidance as confirmed by contrast dye fluoroscopy. CONCLUSIONS: Ultrasound is radiation free, is easy to use, and can provide real-time images in guiding the caudal epidural needle into the caudal epidural space. Ultrasound may therefore be used as an adjuvant tool in caudal needle placement.

Adult↗
PubMed2004

Electrophysiologic abnormalities of auditory and visual information processing in patients with traumatic brain injury.

OBJECTIVE: Through both auditory and visual modalities, we sought to explore the efficacy of event-related potentials in detecting residual cognitive impairments in patients with traumatic brain injury (TBI). DESIGN: Control subjects and TBI patients with favorable recovery were recruited. Pure tone and primary color discrimination tasks were utilized to elicit auditory and visual event-related potentials, respectively. All subjects were instructed to push a response button when they detected the target stimuli. Both behavioral and electrophysiologic responses were obtained simultaneously. We analyzed the event-related potential waveforms and examined the differences in amplitude, latency, behavioral reaction time, and response accuracy. RESULTS: A total of 11 TBI patients and 11 control subjects were tested. Results showed that (1) TBI patients had significantly lower P300 amplitude in both auditory (11.2 vs. 22. 7 microV) and visual (11.6 vs. 20.9 microV) domains, (2) TBI patients had significantly longer P300 latency in both auditory (355 vs. 294 msecs) and visual (376 vs. 341 msecs) modalities, and (3) although there was no significant difference in response accuracy (97.7%vs. 100%), reaction time for both auditory and visual tasks were significantly longer in TBI patients (auditory, 404 vs. 277 msecs; visual, 397 vs. 346 msecs). CONCLUSION: Although TBI patients with good recovery showed similar response accuracy when compared with control subjects, they demonstrated significantly poorer performance in both electrophysiologic and behavioral responses. Diminished amplitudes and prolonged latencies in P300 responses indicate impaired organization and categorization of incoming sensory information; prolonged behavioral reaction times suggest slowing in the response execution process. Clinical and theoretical implications and goals for continued research are discussed.

Adult↗
PubMed2004

Brainstem auditory-evoked potentials as an objective tool for evaluating hearing dysfunction in traumatic brain injury.

Because of the violent nature of traumatic brain injury, traumatic brain injury patients are susceptible to various types of trauma involving the auditory system. We report a case of a 55-yr-old man who presented with communication problems after traumatic brain injury. Initial results from behavioral audiometry and Weber/Rinne tests were not reliable because of poor cooperation. He was transferred to our service for inpatient rehabilitation, where review of the initial head computed tomographic scan showed only left temporal bone fracture. Brainstem auditory-evoked potential was then performed to evaluate his hearing function. The results showed bilateral absence of auditory-evoked responses, which strongly suggested bilateral deafness. This finding led to a follow-up computed tomographic scan, with focus on bilateral temporal bones. A subtle transverse fracture of the right temporal bone was then detected, in addition to the left temporal bone fracture previously identified. Like children with hearing impairment, traumatic brain injury patients may not be able to verbalize their auditory deficits in a timely manner. If hearing loss is suspected in a patient who is unable to participate in traditional behavioral audiometric testing, brainstem auditory-evoked potential may be an option for evaluating hearing dysfunction.

Brain Injuries↗
PubMed2004

Stepping over obstacles to improve walking in individuals with poststroke hemiplegia.

For this study, we evaluated two training interventions for improving gait parameters in individuals with poststroke hemiplegia using a training methodology that required them to step over objects. Gait velocity, step length, ability to step over obstacles, and walking endurance were compared before and after 2 weeks of training and 2 weeks after cessation of training. Twenty subjects with poststroke hemiplegia completed six intervention sessions in which they were asked to step over either virtual objects while walking on a motorized treadmill or real foam objects on a 10 m walkway. With the virtual object training, if either foot collided with the virtual object, a tone sounded and a vibrotactile stimulus was applied to the colliding foot. All subjects tolerated the training sessions well, and no incidences of falling or undue cardiovascular responses occurred. The virtual obstacle training generated greater improvements in gait velocity compared with real training (20.5% vs. 12.2% improvement) during the fast walk test (p < 0.01). Improvements in gait velocity for both training methods were similar in the self-selected walk test (33.3% vs. 34.7% improvement). Overall, subjects showed clinically meaningful changes in gait velocity, stride length, walking endurance, and obstacle clearance capacity as a result of either training method. These changes persisted for 2 weeks posttraining. The inclusion of enhanced safety and visual augmentation may be responsible for the effectiveness of the virtual object intervention. These results demonstrate preliminary evidence for clinical effectiveness of obstacle training for improving gait velocity poststroke. In addition, these results provide evidence for enhanced clinical performance with virtual obstacle training.

Adult↗
PubMed2003

Use of somatosensory-evoked potentials and cognitive event-related potentials in predicting outcomes of patients with severe traumatic brain injury.

OBJECTIVE: This study was performed to evaluate the usefulness of somatosensory-evoked potentials (SEPs) and cognitive event-related potentials (ERPs) in predicting functional outcomes of severe traumatic brain injury patients. DESIGN: Prospective study of 22 patients with severe traumatic brain injury. Demographic information, Glasgow Coma Scale, and electrophysiologic measurements were recorded. Functional outcomes, as quantified by the Glasgow Outcome Scale-Extended, were obtained. RESULTS: Bilateral absence of median nerve SEP was strongly predictive of the worst functional outcome. The specificity and positive predictive value of absent SEP for predicting death or persistent vegetative state at 6 mo after traumatic brain injury were as high as 100%. If the definition of unfavorable outcome was expanded to include Glasgow Outcome Scale-Extended 1-4, absence of ERP was equivalent to the absence of SEP in specificity and positive predictive value. On the other hand, normal ERPs showed higher sensitivity and negative predictive value for prognosticating the best outcomes compared with normal SEPs. If the definition of favorable outcome was expanded to include Glasgow Outcome Scale-Extended 5-8, ERP was still superior to SEP for prognosticating good outcome. Interestingly, the highest sensitivity and negative predictive value for favorable outcomes were associated with the presence of any discernible waveform. CONCLUSIONS: Although median nerve SEP continues to make reliable prediction of ominous outcome in severe traumatic brain injury, the addition of the speech-evoked ERPs may be helpful in predicting favorable outcomes. The strength of the latter test seems to complement the weakness of the former.

Adolescent↗