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Biomedical subjects

L R Robinson

Publications and source records attributed to L R Robinson.

At least 19 recordsLinked to original sources
PubMed2001

Back pain as a secondary disability in persons with lower limb amputations.

OBJECTIVE: To evaluate the frequency, duration, intensity, and interference of back pain in a sample of persons with lower limb amputations. DESIGN: Retrospective, cross-sectional survey. SETTING: Community-based survey from clinical databases. PARTICIPANTS: Participants who were 6 or more months post lower limb amputation (n = 255). INTERVENTION: An amputation pain survey that included several standardized pain measures. MAIN OUTCOME MEASURES: Frequency, duration, intensity, and interference of back pain. RESULTS: Of the participants who completed the survey (return rate, 56%), 52% reported experiencing persistent, bothersome back pain. Of these, 43% reported average back pain intensity in the mild range (1-4 on 0-10 rating scale) and 25% reported pain of moderate intensity (5-6 on 0-10 scale). Most respondents with back pain rated the interference of their pain on function as none to minimal. However, nearly 25% of those with back pain described it as frequent, of severe intensity (>or=7 on 0-10 scale), and as severely interfering with daily activities including social, recreational, family, and work activities. CONCLUSIONS: Back pain may be surprisingly common in persons with lower limb amputations, and, for some who experience it, may greatly interfere with function.

Activities of Daily Living↗
PubMed2000

Somatosensory potentials, CSF creatine kinase BB activity, and awakening after cardiac arrest.

OBJECTIVE: To examine the utility of somatosensory evoked potential (SEP) peaks and CSF creatine kinase BB isoenzyme activity (CKBB) in predicting nonawakening from coma due to cardiac arrest. BACKGROUND: Accurate predictors of neurologic outcome in patients comatose after cardiac arrest are needed to improve medical decision making. METHODS: A total of 72 comatose patients had bilateral median SEPs, and of these, 52 had CSF and CKBB. Awakening was defined as following commands or having comprehensible speech. Both short (N1) and long (N3) latency SEP peaks were analyzed. Nonparametric analyses were used. RESULTS: For patients who had both tests, CKBB > or = 205 U/L predicted nonawakening with a sensitivity of 49% and a specificity of 100%. Bilateral absence of the N1 peak predicted nonawakening with a sensitivity of 53% and a specificity of 100%. Using CKBB > or = 205 U/L, bilaterally absent SEP N1 peaks, or both predicted nonawakening with a sensitivity of 69% and a specificity of 100%. Using CKBB > or = 205 U/L, bilaterally absent N1 peaks, bilateral N3 > or = 176 msec or absent, or some combination predicted nonawakening with a sensitivity of 78% and a specificity of 100%. CONCLUSION: The combination of an absent N1 peak and elevated CKBB performs better than either alone in predicting nonawakening after cardiac arrest. Prolonged or absent N3 latency may increase sensitivity. These results should be interpreted with caution given the small number of patients and the possibility of a self-fulfilling prophecy.

Adolescent↗
PubMed2000

Traumatic injury to peripheral nerves.

This article reviews the epidemiology and classification of traumatic peripheral nerve injuries, the effects of these injuries on nerve and muscle, and how electrodiagnosis is used to help classify the injury. Mechanisms of recovery are also reviewed. Motor and sensory nerve conduction studies, needle electromyography, and other electrophysiological methods are particularly useful for localizing peripheral nerve injuries, detecting and quantifying the degree of axon loss, and contributing toward treatment decisions as well as prognostication.

Electromyography↗
PubMed2000

Test-retest reliability of combined sensory index: implications for diagnosing carpal tunnel syndrome.

When compared to single nerve conduction tests, the combined sensory index (CSI) has been shown previously to have superior sensitivity and specificity for diagnosing carpal tunnel syndrome. The CSI is the sum of (1) median-ulnar ring finger antidromic latency difference at 14 cm (ring-diff); (2) median-radial thumb antidromic latency difference at 10 cm (thumb-diff); and (3) median-ulnar midpalmar orthodromic latency difference at 8 cm (palm-diff). To evaluate the reliability of single nerve conduction tests (ring-diff, thumb-diff, and palm-diff) vs. a combined summary variable (CSI), we conducted a prospective study during which the same investigator performed test and retest sessions on one hand of 32 subjects. Results showed that the CSI had the highest test-retest reliability (Spearman rho = 0.95), when compared with ring-diff, thumb-diff, and palm-diff (Spearman rho = 0.67, 0.75, and 0.74, respectively). Therefore, we propose the use of the CSI as not only an accurate but also a reliable method for diagnosing carpal tunnel syndrome.

Adult↗
PubMed2000

Lumbosacral plexopathy in pelvic trauma.

We reviewed the electrophysiologic data and the etiology of lumbosacral plexopathy in 22 consecutive patients with pelvic trauma referred for electromyography (EMG). Most (68%) patients had sacral fractures or sacroiliac joint separation, 14% had acetabular fractures, and 9% had femoral fractures. Lumbosacral plexopathy was significantly more common (P = 0.0026) among patients with sacral fractures (incidence of 2.03%) than among the entire population of patients with pelvic and acetabular fractures (overall incidence 0. 7%). Patients with acetabular and femoral fractures may have suffered injury to multiple proximal nerves originating from the plexus rather than injury to the plexus, as confirmed by magnetic resonance imaging (MRI) neurogram in select cases.

Action Potentials↗
PubMed2000

Optimizing the number of tests for carpal tunnel syndrome.

The combined sensory index (CSI), the sum of three latency differences, median-ulnar across the palm (palmdiff), median-ulnar to the ring finger (ringdiff), and median-radial to the thumb (thumbdiff), has higher sensitivity and reliability for carpal tunnel syndrome than individual tests. The objective in this study was to develop an approach that minimizes testing but maximizes accuracy. We retrospectively studied 300 hands. There were endpoints for individual tests that confidently predicted the CSI; for ranges between these endpoints, further testing was required. These ranges were: palmdiff 0-0.3 ms; ringdiff 0.1-0.4 ms; and thumbdiff 0.2-0.7 ms. One may use a strategy in which more tests are performed when results are in these ranges. This approach can allow accurate diagnosis with fewer tests when values are extreme, yet uses the greater diagnostic power of more tests when values are midrange.

Adult↗
PubMed2000

Serum positive botulism with neuropathic features.

A 32-year-old man presented with multiple cranial neuropathies and his serum was positive for botulism type B. However, serial electrodiagnostic studies were consistent with a primarily neuropathic process, such as Fisher syndrome, rather than a neuromuscular junction disorder. Electrodiagnostic study findings in patients with presumed neuromuscular junction disorders may mimic findings suggestive of a neuropathic process, or the bioassay for botulism may be falsely positive in patients with Fisher Syndrome.

Adult↗
PubMed2000

Chronic phantom sensations, phantom pain, residual limb pain, and other regional pain after lower limb amputation.

OBJECTIVES: To determine the characteristics of phantom limb sensation, phantom limb pain, and residual limb pain, and to evaluate pain-related disability associated with phantom limb pain. DESIGN: Retrospective, cross-sectional survey. Six or more months after lower limb amputation, participants (n = 255) completed an amputation pain questionnaire that included several standardized pain measures. SETTING: Community-based survey from clinical databases. PARTICIPANTS: A community-based sample of persons with lower limb amputations. MAIN OUTCOME MEASURES: Frequency, duration, intensity, and quality of phantom limb and residual limb pain, and pain-related disability as measured by the Chronic Pain Grade. RESULTS: Of the respondents, 79% reported phantom limb sensations, 72% reported phantom limb pain, and 74% reported residual limb pain. Many described their phantom limb and residual limb pain as episodic and not particularly bothersome. Most participants with phantom limb pain were classified into the two low pain-related disability categories: grade I, low disability/low pain intensity (47%) or grade II, low disability/high pain intensity (28%). Many participants reported having pain in other anatomic locations, including the back (52%). CONCLUSIONS: Phantom limb and residual limb pain are common after a lower limb amputation. For most, the pain is episodic and not particularly disabling. However, for a notable subset, the pain may be quite disabling. Pain after amputation should be viewed from a broad perspective that considers other anatomic sites as well as the impact of pain on functioning.

Adult↗
PubMed2000

Electrodiagnostic evaluation of traumatic nerve injuries.

This article reviews the techniques of motor and sensory nerve conduction studies and needle electromyography methods, which are particularly useful for localizing nerve injuries in upper extremity and hand trauma. Included are details of methods for detecting and quantifying the degree of axon loss and for using this information to make treatment decisions and predict outcomes. The epidemiology and classification of traumatic peripheral nerve injuries, the effects of these injuries on nerve and muscle, and the means by which electrodiagnosis is used to help classify the injury are described. An overview of recovery mechanisms also is presented.

Action Potentials↗
PubMed1999

Laryngeal electromyographic findings in Charcot-Marie-Tooth disease type II.

Charcot-Marie-Tooth disease is a hereditary motor and sensory neuropathy that exhibits progressive muscular atrophy in the limbs, beginning with the lower extremities. It is now understood to be a heterogeneous group of disorders that can be differentiated both clinically and genetically. In Charcot-Marie-Tooth disease type II C, axonal neuropathy, diaphragm weakness, and vocal cord paralysis are described within kindreds. We used laryngeal electromyography to study a patient with this disorder. This technique has potential in the diagnosis of Charcot-Marie-Tooth disease type II.

Adult↗
PubMed1999

Idiopathic bilateral vocal fold weakness.

OBJECTIVE: To describe an unrecognized clinical entity, idiopathic bilateral vocal fold weakness, and propose recommendations regarding the diagnosis and management of these cases. STUDY DESIGN: Retrospective, nonrandomized case study. METHODS: All cases of bilateral vocal fold weakness evaluated at the University of Washington Voice Disorders Clinic between 1991 to 1998 were reviewed. RESULTS: Four patients with bilateral laryngeal weakness were determined to have idiopathic bilateral vocal fold paresis following exhaustive workups, including videostroboscopy, bilateral laryngeal electromyography (EMG), neurological consultation, and other pertinent studies. CONCLUSIONS: Performing bilateral laryngeal EMG is an essential aspect of the workup of any laryngeal weakness case, particularly if the etiology is unknown on presentation. Idiopathic bilateral vocal fold weakness is an underrecognized but real clinical diagnosis that will become more familiar with the increasing utilization of laryngeal EMG in clinical situations.

Adult↗
PubMed1998

Strategies for analyzing nerve conduction data: superiority of a summary index over single tests.

We compared three strategies for diagnosing carpal tunnel syndrome: using a single test; requiring one, two, or three of three tests to be abnormal; or utilizing a single summary variable incorporating data from three tests. Sixty-five hands of subjects without clinical carpal tunnel syndrome (CTS) were compared with 66 hands with clinical CTS. Three latency differences were measured: median-ulnar (8 cm) midpalmar orthodromic (palmdiff); median-ulnar ring finger (14 cm) antidromic (ringdiff); and median-radial thumb (10 cm) antidromic (thumbdiff). The combined sensory index (CSI) was the sum of these three differences. Sensitivity for the tests was palmdiff 69.7%, ringdiff 74.2%, thumbdiff 75.8%, and CSI 83.1%. Specificity was 95.4-96.9%. Requiring one, two, or three of three tests to be abnormal yielded sensitivities of 84.8%, 74.2%, or 56.1%, respectively, but specificities of 92.3%, 98.5%, and 100%, respectively. We conclude that a combined index improves diagnostic classification over use of single test results.

Carpal Tunnel Syndrome↗
PubMed1998

New laryngeal muscle weakness in post-polio syndrome.

The authors describe the clinical presentations of post-polio laryngeal muscle weakness in three patients with prior polio infection who presented with new complaints including slowly progressive dyspnea, dysphagia, and/or hoarseness. Evaluations by laryngeal videostroboscopy and electromyography revealed vocal cord abductor and/or adductor weakness, recurrent posterior glottic web in one case, and, in the two patients who agreed to electromyography, evidence of prior denervation and reinnervation in laryngeal muscles. Treatment was directed at attempting to maintain an airway and optimize vocal quality. One patient benefitted from tracheostomy, one benefitted from vocal cord medialization, and one benefitted from resection of interarytenoid scarring. The authors conclude that diagnosis of laryngeal post-polio syndrome is facilitated by laryngeal electromyography. Interventions directed at maintaining an appropriate airway and optimizing vocal quality may be helpful.

Aged↗
PubMed1998

Respiratory failure and hypoventilation secondary to neurosarcoidosis.

We report a patient manifesting severe hypoventilation resulting from diaphragmatic paresis secondary to sarcoid. A 34yr-old female presented with chest pain. Chest radiograph revealed hilar adenopathy and left pleural effusion; computed tomography scan showed a 2-cm solid lesion in the aorto-pulmonary window. Bronchoscopy and thoracentesis failed to further identify the nature of the lesion. An episode of aspiration resulted in cardiopulmonary arrest, necessitating cardiopulmonary resuscitation. Electrodiagnostic findings were consistent with bilateral phrenic neuropathy with axon loss, suggesting a poor prognosis. Biopsy via mediastinoscopy revealed noncaseating confluent granulomas with many multinucleated epithelioid histiocytes consistent with the diagnosis of sarcoidosis. Eight months after initial diagnosis and immunosuppressive treatment, the patient was successfully extubated and became ambulatory. Upon tapering her prednisone, however, she became dyspneic and manifested hypoventilation secondary to muscle weakness. Her corticosteroids were increased, but she eventually died of an opportunistic lung infection 2 yr later. This case establishes phrenic neuropathy and peripheral polyneuropathy secondary to neurosarcoidosis as a cause of respiratory failure. It also illustrates the utility of phrenic and diaphragmatic electrodiagnosis in the evaluation as well as prognostication of such lesions.

Adult↗
PubMed1998

Effect of nerve block on sural amplitude during remote muscle contraction.

We previously reported that the median sensory nerve action potentials (SNAPs) increased in amplitude during both near (3) and remote (4) muscle contraction. The objective of the present project was to begin to study the pathway by which this occurred. The sural amplitude was measured after one min. of isometric biceps contraction and compared pre and post lidocaine nerve block in 10 healthy subjects. The baseline was defined as the least amount of current needed to elicit a minimal sural response pre contraction. This level of stimulus remained constant throughout the experiment. Results showed that the sural amplitude peaked 4 min. after muscle contraction. An 8.1 microV increase in sural amplitude from baseline was noted pre injection as 5 min. post contraction, and an increase of 13.4 microV was noted comparing pre to post injection amplitudes at the same time. Statistical analysis using two-way interaction comparing the time courses pre and post injection showed a 92% chance the responses were dissimilar Post hoc least significant difference (LSD) analyses were significant at 4 min. (p = .005) and 6 min. (p = 0.29) post contraction. In conclusion, the increase in sural amplitude after remote muscle contraction was no longer apparent after proximal sural nerve block. This suggests that the nerve itself is required in the final common pathway for the transmission of this induced signal.

Action Potentials↗
PubMed1998

Considerations in reference values for nerve conduction studies.

Despite the universal application of reference values, understanding their production and underlying limitations is often overlooked. Without a deeper consideration for this issue, opportunities for treatment may be missed or misdiagnosis may occur. This article reviews relevant biostatistical issues in the generation of reference intervals and subsequent errors that may occur. Further discussion includes recommendations on how to correct statistical errors, as well as more recent methods for distinguishing between "healthy" and "diseased."

Biometry↗
PubMed1997

AAEM minimonograph #47: normative data in electrodiagnostic medicine. ff.

This article reviews, without mathematics, the important principles governing the acquisition and use of normative data in electrodiagnostic medicine. Common flaws in neurophysiological normative data include vague clinical criteria for establishing freedom from disease, samples that are too small and inadequately stratified, and application of Gaussian statistics to non-Gaussian variables. Other problematic issues concern the trade-off between permissible false-positivity and false-negativity in defining the limits of normative from sample data, test-retest variability, and the use of multiple independent test measurements in each electrodiagnostic examination. The following standards for normative data are proposed: (1) standardized objective determination of freedom from disease; (2) appropriately large sample of normal subjects; (3) proportional statification of normal subjects for known relevant variables; (4) test of Gaussian fit for application of Gaussian statistics; and (5) data presentation by percentiles when Gaussian fit is in doubt. Many existing normative studies in clinical neurophysiology do not meet these standards. High-quality normative data, readily accessible, is essential for the accurate electrodiagnosis of neuromuscular diseases.

Electromyography↗