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CONTEXT: In the evaluation of patients with upper limb symptoms, electrodiagnosis (EDX) provides valuable information regarding neurological disorders such as radiculopathies and entrapment neuropathies. What is less clear from the literature is whether or not EDX findings contribute to the prediction of outcomes. OBJECTIVE: In order to examine the relationship between EDX findings and outcomes, this pilot study was conducted. METHODS: Thirty-eight patients with neck and upper limb symptoms who underwent EDX testing and standardized data collection as part of a previously conducted prospective study were contacted by telephone a mean of 30 months after testing to determine their outcomes. Patients were classified into three categories according to EDX findings: i) 15 had radiculopathies, ii) 13 had normal studies, and iii) 10 had other electrodiagnostic findings. Primary outcome variables of interest were the interval verbal pain rating scale and a subjective report of symptom improvement. RESULTS: None of the patients with radiculopathies or normal studies worsened, whereas 30% of persons with other findings on EDX significantly worsened. CONCLUSIONS: The findings from this small pilot study raise many questions regarding electrodiagnosis and its relationship to outcome. A larger prospective study is necessary to fully examine this relatively unexplored but potential use for EDX testing.

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OBJECTIVE: To document and examine the use, satisfaction, and problems with prosthetic devices among persons who suffered a trauma-related lower limb amputation. DESIGN: Abstracted medical records and follow-up interview data were collected for a retrospective cohort of persons with a lower limb trauma-related amputation who received their acute care at the University of Maryland R. Adams Cowley Shock Trauma Center, Baltimore, MD, between 1984 and 1994. Patients with spinal cord injury, traumatic brain injury, or only toe amputations were excluded. RESULTS: There were 146 patients identified. Of those, 9% died during the acute admission and 3.5% died after discharge. Seventy-eight amputees were available for interview (68% response rate). The majority of those interviewed were male (87%), and two-thirds had undergone amputation before age 40 yr. Nearly 95% had a prosthesis and wore it an average of 80 hr (SD = 33) per week. Despite high use, only 43% reported being satisfied with the comfort of their prosthesis. About one-quarter of all users reported problems with wounds, skin irritation, or pain. Traumatic amputees used an average of four prostheses since injury, about one new prosthesis every 2 yr. Statistical analyses revealed that males reported higher prosthetic use (P < 0.01). Higher Injury Severity Score negatively impacted on prosthetic use (P < 0.01). Phantom pain negatively influenced reported satisfaction with the prosthesis (P < 0.03) CONCLUSIONS: Although almost all persons living with trauma-related amputations use prosthetic devices, the majority are not satisfied with prosthetic comfort. Phantom pain and residual limb skin problems are also common afflictions in this population.

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Electrodiagnosis is an important part of the diagnostic evaluation for patients with suspected neuromuscular diseases. The electrodiagnostician should maintain a broad, inclusive differential diagnosis and tailor the examination using a sound conceptual framework. A clear understanding of what is normal provides the proper foundation on which to judge electrodiagnostic findings. Many peripheral neuromuscular conditions manifest themselves in characteristic ways on EMG and nerve conduction testing, making them identifiable to the skilled electrodiagnostic medicine consultant.

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OBJECTIVE: To determine the optimal electromyography screening examination of the upper limb that ensures detection of those cervical radiculopathies, which can be electrodiagnostically confirmed, yet minimizes the number of muscles studied. DESIGN: A prospective multicenter study was conducted from May 1996 to September 1997 at five institutions. Patients who were referred to participating electrodiagnostic laboratories with suspected cervical radiculopathy were recruited. A standard set of muscles were examined by needle electromyography. Patients with electrodiagnostically confirmed cervical radiculopathies, based on electromyography findings, were selected for analysis. Muscle screens were tested against this group to determine whether the screen identified the patients with radiculopathy. RESULTS: There were 101 patients with cervical radiculopathies representing all cervical root levels. When paraspinal muscles were one of the screening muscles, five muscle screens identified 90% to 98% of radiculopathies, six muscle screens identified 94% to 99%, and seven muscle screens identified 96% to 100%. When paraspinal muscles were not part of the screen, eight distal limb muscles recognized 92% to 95% of radiculopathies. CONCLUSION: This study demonstrated that six muscle screens including paraspinal muscles yielded consistently high identification rates. Studying additional muscles led to marginal increases in identification.

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OBJECTIVE: Knutsson (Acta Orthopaed Scand (1961) 1) published a classic thesis comparing lower limb electromyography (EMG) results with intra-operative findings for 206 patients with sciatica. This unique and detailed work presented a rare opportunity to again use this data and determine the optimal number of muscles in a screening examination; a different study aim to that of the original investigator. METHODS: Data from Knutsson (1961) were used to determine the identification rates and sensitivities with respect to clinical and intra-operative diagnostic standards, for various muscle screens. RESULTS: Selected 4 muscle EMG screens identified over 97% of EMG confirmed radiculopathies and over 89% of surgically confirmed radiculopathies. CONCLUSIONS: These findings underscore the utility of 4 muscle EMG screens in the evaluation of patients with suspected lumbosacral radiculopathy.

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OBJECTIVE: The objective of this study was to determine prospectively the optimal electromyographic screening examination of the lower limb that ensures identification of those lumbosacral radiculopathies that can be electrodiagnostically confirmed, yet minimizes the number of muscles studied. DESIGN: A prospective multicenter study was conducted from May 1996 to September 1997. Patients with suspected lumbosacral radiculopathy referred to participating electrodiagnostic laboratories were recruited and examined by needle electromyography using a standard set of muscles. Patients with electrodiagnostically confirmed lumbosacral radiculopathies were selected for analysis. Various muscle screens were tested against this group of patients with radiculopathies to determine the frequency with which each screen identified the patient with radiculopathy. RESULTS: There were 102 patients identified. When paraspinal muscles were one of the screening muscles, four-muscle screens identified 88-97% of the radiculopathies, five-muscle screens identified 94-98%, and six-muscle screens 98-100%. When paraspinal muscles were not part of the screen, identification rates were lower for all screens, and eight distal muscles were necessary to identify about 90% of the radiculopathies. CONCLUSIONS: Six-muscle screens with paraspinal muscles yielded consistently high identification rates. Studying additional muscles produced no improvements in identification.

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Since its introduction, magnetic resonance imaging has become an indispensable diagnostic tool for the physiatrist evaluating potential spinal cord pathology. Despite ongoing advances in MRI technology and subsequent improved sensitivity, significant pathology can still be missed. In this article, we review the clinical role of contrast enhancement in visualizing many forms of spinal cord pathology.

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OBJECTIVE: To determine the effectiveness of medical history and physical examination in predicting electrodiagnostic outcome in patients with suspected cervical radiculopathy. METHODS: Data on 183 subjects prospectively collected at five different electrodiagnostic laboratories were analyzed (96 cervical radiculopathies, 45 normal studies, and 42 abnormal electrodiagnostic findings other than radiculopathy). The sensitivity, specificity, positive predictive value, negative predictive value, and odds ratios were determined for symptoms and neurologic signs. RESULTS: Symptoms of numbness, weakness, and tingling were associated with twice the probability of having abnormal electrodiagnostic study results in general, yet were not helpful in identifying a cervical radiculopathy. All single and combined physical examination components had poor sensitivities, with the exception of weakness, but much higher specificities. Patients with either weakness or reduced reflexes on physical examination were up to five times more likely to have abnormal electrodiagnostic findings. In subjects with any abnormal neurologic sign, the sensitivity improved to 84%, the positive predictive value was 79%, but the specificity was low (44%). Of those subjects with normal physical examination results, almost one half had an abnormal electrodiagnostic study result (negative predictive value 52%). CONCLUSIONS: In a population of patients with suspected cervical radiculopathy, medical history and physical examination are helpful yet not sufficient to predict the electrodiagnostic outcome.

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OBJECTIVES: A long-held notion in the electrodiagnostic literature is that paraspinal muscles tend to show spontaneous activity (fibrillations and positive sharp waves) on needle electromyography, early on in a lumbosacral radiculopathy, and that more distal muscles become abnormal later in the disease process. The purpose of this study was to determine whether paraspinal muscle and other major proximal and distal muscle spontaneous activity is related to a lumbosacral radiculopathy symptom duration. METHODS: A multicenter, prospective study that collected standard information on history, physical examination, and electrodiagnostic findings in patients with electrodiagnostically confirmed lumbosacral radiculopathies was undertaken. RESULTS: Multivariate probit analyses of 96 patients identified with a lumbosacral radiculopathy showed no evidence of correlation between spontaneous activity in the paraspinal muscles and symptom duration. Symptom duration was also nonsignificant in nine of the remaining ten lower limb muscles analyzed. CONCLUSION: These findings emphasize the limitations of using symptom duration when interpreting electrodiagnostic findings in lumbosacral radiculopathy.

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OBJECTIVE: To determine the extent to which the history and physical examination predict the outcome of the electrodiagnostic (EDX) evaluation in patients with suspected lumbosacral radiculopathy. DESIGN: Data for 170 subjects referred for low-back and lower limb symptoms were prospectively collected at five EDX laboratories. The sensitivity, specificity, positive and negative predictive values, and odds ratios were determined for symptoms and neurologic signs. RESULTS: Symptoms were not significantly associated with an EDX study or a lumbosacral radiculopathy. The physical examination was better at predicting that an EDX study would be abnormal in general than it was at predicting a lumbosacral radiculopathy in particular. Of those subjects with normal physical examinations, 15%-18% still had abnormal EDX findings. CONCLUSIONS: In a population of patients referred for an EDX study, the history and physical examination alone cannot reliably predict electrodiagnostic outcome.

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OBJECTIVE: To examine the long-term outcomes of persons undergoing trauma-related amputations, and to explore factors affecting their physical, social, and mental health and the role of inpatient rehabilitation in improving such outcomes. DESIGN: Abstracted medical records and interview data sought for a retrospective cohort of persons who had undergone a lower-limb trauma-related amputation. PARTICIPANTS: Patients identified with a principal or secondary diagnosis of a trauma-related amputation to the lower extremity at the University of Maryland Shock Trauma Center between 1984 and 1994. Patients with spinal cord injury or traumatic brain injury were excluded. RESULTS: Of 146 patients who had trauma-related amputations to the lower limb at the University of Maryland Shock Trauma Center during the study period, nearly 9% died during the acute admission and 3.5% died after discharge. About 87% of all trauma-related amputations involved males, and roughly three quarters involved white persons. About 80% of all amputations occurred before age 40. The health profile of traumatic amputee subjects interviewed in the study (n = 78, 68% response rate) was systematically lower than that of the general US population for all SF-36 scores. The differences in profiles were largest among SF-36 scales sensitive to differences in physical health status, particularly physical functioning, role limitations due to physical health, and bodily pain. About one fourth of persons with a trauma-related amputation reported ongoing severe problems with the residual limb, including phantom pain, wounds, and sores. The number of inpatient rehabilitation nights significantly improved the ability of patients with amputation to function in their physical roles, increased vitality, and reduced bodily pain. Inpatient rehabilitation was also significantly correlated with improved vocational outcomes. CONCLUSIONS: These findings suggest a substantial effect of inpatient rehabilitation in improving long-term outcomes of persons with trauma-related amputations.

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The purpose of this multicenter study was to prospectively examine whether denervation in paraspinal muscles (PSM) and in other major proximal and distal muscles is related to symptom duration in cervical radiculopathies (CRs). Information was collected on 93 electrodiagnostically confirmed CRs using standardized history, physical examination, and electromyographic (EMG) screens. Multivariate, maximum-likelihood estimates showed no evidence of correlation between PSM spontaneous activity and symptom duration. Symptom duration was also nonsignificant in eight of the remaining nine upper limb muscles analyzed. We conclude that the probability of spontaneous activity is not related to symptom duration. Clinicians, therefore, should refrain from interpreting electrodiagnostic findings based upon duration of symptoms.

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Many disorders affect the trigeminal nerve, highlighting the need for electrodiagnostic methods to evaluate this cranial nerve. The purpose of this study was to develop and refine clinical nerve conduction techniques for examining mylohyoid late responses and to establish normative clinical data. Intraoral stimulation of the mylohyoid nerve was performed on normal volunteers using a pediatric stimulator taped to a tongue depressor. Mylohyoid direct and late responses were recorded with surface electrodes over the mylohyoid muscles. Mylohyoid late responses with supraorbital nerve stimulation and blink reflexes were also elicited. Fifty-four subjects, 65% females, with an average age of 39.2 (standard deviation, 13.4) yr, were studied. Direct mylohyoid responses were elicited in all subjects with a mean of 1.8 (standard deviation, 0.3) ms and amplitude of 4.1 (standard deviation, 1.4) mV. Late responses occurred in 94% ipsilaterally at an average latency of 32.4 (standard deviation, 6.5) ms and in 90% contralaterally at 32.4 (standard deviation, 5.6) ms. Two distinct late responses, the second occurring at an average of 72.3 (standard deviation, 12.4) ms with intraoral stimulation were noted in 25% of subjects. Only 11% of subjects had mylohyoid late responses with supraorbital stimulation. Blink (R1) reflexes occurred in 89% (10.9 ms; standard deviation, 0.7 ms), ipsilateral R2 responses in 88% (35.2 ms; standard deviation, 3.4 ms), and contralateral R2 responses in 69% (36.2 ms; standard deviation, 4.0 ms). Mylohyoid late responses are present in most normal subjects. The neuroanatomical pathways mediating these responses require delineation. These nerve conduction techniques may be useful in evaluating patients with suspected trigeminal nerve disorders.

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The purpose of this study was to determine whether paraspinal and other major proximal and distal muscle spontaneous activity (SA) is related to cervical radiculopathy (CR) symptom duration. A multivariate analysis of 124 (retrospectively identified) electrodiagnostically confirmed CRs was used to test these hypotheses. The results showed no evidence of correlation between SA and symptom duration for any of the upper limb muscles analyzed.

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A long held notion in the electrodiagnostic literature is that paraspinal muscles tend to show electromyographic abnormalities early on in a lumbosacral radiculopathy and that more distal muscles become abnormal later in the disease process. The purpose of this study was to determine whether paraspinal muscles and other major proximal and distal muscle abnormalities are related to lumbosacral radiculopathy symptom duration. A multivariate logit analysis of 139 patients (retrospectively identified) with electrodiagnostically confirmed lumbosacral radiculopathies was used to test these hypotheses. Maximum likelihood estimates showed no evidence of correlation between abnormal paraspinal muscles and symptom duration. Symptom duration was also insignificant for the remaining five lower limb muscles analyzed. We conclude that the probability of having electromyographic abnormalities is not related to symptom duration. A prospective study is needed to confirm these findings. Nonetheless, clinicians should use caution when interpreting electrodiagnostic findings based on symptom duration.

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OBJECTIVE: To examine patterns of trauma-related amputations over time by age and gender of the patient and by level and type of amputation, and to explore factors affecting acute care length of stay and discharge to inpatient rehabilitation. DESIGN: Population-based hospital discharge data for Maryland from 1979 through 1993. PARTICIPANTS: Patients (N = 6,069) discharged with either (1) a principal or secondary diagnosis of a trauma-related amputation to the upper or lower extremity or (2) a procedure code for a lower or upper limb amputation in combination with a principal diagnosis of an extremity injury or injury-related complication. RESULTS: Incidence of major amputations declined 3.4% (p < .05) annually from 1.88 per 100,000 in 1979 to 1.07 per 100,000 in 1993. Incidence of minor amputations declined 4.8% (p < .05) annually from 10.8 per 100,000 in 1979 to 4.7 per 100,000 in 1993. Acute care length of stay for trauma-related amputations declined 40% over the study period and was significantly affected by the patient's payer source, amputation level, and injury characteristics. Of the patients with a major amputation, 15% were discharged to inpatient rehabilitation; 60% were discharged directly home. More proximal amputation levels, presence of severe injuries to other body systems, and acute care at a designated trauma center significantly increased the likelihood of disposition to inpatient rehabilitation. The leading causes of trauma-related amputation were injuries involving machinery (40.1%), powered tools and appliances (27.8%), firearms (8.5%), and motor vehicle crashes (8%). CONCLUSIONS: Findings suggest a substantial decline in incidence rates of both major and minor amputations over the 15-year study period, a low rate of disposition to inpatient rehabilitation services of patients sustaining major amputations, and an apparent role of firearms as a cause of trauma-related amputations in patients younger than 25 years of age. The consequences of increasingly shorter acute care hospital stays and low rates of discharge to inpatient rehabilitation on the long-term outcomes of persons who have had traumatic amputation should be examined.

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This study uses theoretic derivations, statistical simulations, and empirical estimations to compare two ways of deriving reference values for side-to-side differences in nerve conduction parameters of healthy subjects. The two methods involve using the side-to-side differences (STSD) and the absolute values of the STSD (AVSTSD). The theoretic derivations showed that the population reference value of the AVSTSD is greater than the STSD reference values by 0.18%. Simulation studies showed that the AVSTSD yields greater sampling errors than the STSD method when establishing the reference values for nerve conduction parameters. However, the sampling variability is substantially reduced by using study samples of greater than 50, and the differences between the two methods in sampling errors are trivial as sample size approaches 100. Using H reflex (HR) and extensor digitorum brevis reflex (EDBR) clinical data, the two methods were compared. In contrast to the small theoretic differences in reference values, the AVSTSD method overestimated the reference value by 0.5 ms for the EDBR and 0.1 ms for the H reflex, when using data from a population sample, increasing the type II error (reducing sensitivity) for the EDBR. The STSD method is recommended for establishment of normal values and for clinical comparisons.

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This article describes nerve conduction studies of the deep temporal nerve (DTN) and the mylohyoid nerve (MHN) motor branches of the trigeminal nerve. These nerves were stimulated intraorally with a pediatric surface stimulator. Compound muscle action potentials were recorded over the temporalis and mylohyoid muscles with surface electrodes. Forty-two subjects were studied. In all subjects the MHN response was elicited bilaterally, giving an upper latency limit of 2.3 ms. The mean MHN amplitude was 4.9 mV (SD = 1.8 mV, minimum = 1.3 mV). The maximal side-to-side amplitude difference was 0.4 ms. and the maximal side-to-side amplitude difference was 2.2 mV. The DTN response was only elicited bilaterally in 25 (60%) subjects. The average DTN latency was 2.1 ms (SD = 0.3, maximum = 2.7 ms). The average DTN amplitude was 4.3 mV (SD = 2.0, minimum = 0.3 mV). The MHN responses were the least technically demanding, and were more consistently elicited than the DTN responses. These nerve conduction techniques should prove useful in patients with trigeminal nerve disorders.

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