Electrodiagnostic Consultation Research Articles

Facial Palsy: A Retrospective Study of 416 Cases Based on Electrodiagnostic Consultation

Background: Facial nerve palsy (FP) is a frequent neurological condition caused mostly by Bell´s Palsy (BP). Objectives: The main objective of this study is to describe electrophysiological parameters in a retrospective 28-year review of 416 cases of FP based on electrodiagnostic consultation. Methods: In total, 520 exams from 416 patients over a 28-year period were reviewed. Sex, age, etiology, comorbidities, and variables from electroneurography and needle electromyography were analyzed. Cases were grouped as BP (70.7%), injury (16.4%), iatrogenic (10.3%) and Ramsay Hunt syndrome (RHS) (2.6%). Results: The mean age was 41 years (3-82), 53.4% female. Diabetes was the most frequent comorbidity. Estimated Axon Loss (EAL), >90%, was found in 50% of the cases, mainly in the iatrogenic group. The amplitude drop of the Compound Muscle Action Potentials (CMAPs) was proportional in the Orbicularis Oculi, Orbicularis Oris and Nasalis muscles. The absence of CMAPs was more frequent in the iatrogenic group and less frequent in the BP one. Bell´s palsy associated with diabetes was more severe. The R1 latency (blink reflex) was significantly longer in the BP group (P>0.001). Synkinesis due to the misdirection of regenerating axons was much more frequent in the BP and RHS groups. Conclusion: Bell´s palsy was the most common cause. The EAL was equal in all facial branches. Facial nerve inexcitability was more frequent in the iatrogenic/injury groups. The R1 latency was found to be prolonged in the BP group and the only good prognosis indicator in a few cases. Misdirection reinnervation was more frequent in BP and RHS groups. There was no sex or side predominance.

The usefulness of electrodiagnostic consultation in an outpatient clinic

The aim of this study was to record all patients referred to a private outpatient clinic for electrodiagnostic consultation during one calendar year.The demographic data of the patients, the specialty of the referring physicians, the referral diagnosis, the electromyographic (EMG) diagnosis and the concordance of referral and EMG diagnosis among all the referring physician’s specialties were recorded.There were one thousand patients (385 men and 615 women). 65.7% of the patients were referred from orthopedists and 22.4% from neurologists. EMG was normal in 498 patients (49.8%). Abnormal in 47.3% of the patients referred by orthopedists and 58.9% of those referred by neurologists. Carpal tunnel syndrome (CTS) was the most frequent electrophysiological diagnosis (26.8%), followed by polyneuropathy (8.9%), radiculopathy (7.1%) and mononeuropathy (4.6%).In this study electrodiagnostic consultation was abnormal in only half of the referred patients. The high proportion of normal EDX tests in this study denotes the need for more accurate clinical diagnosis in order to reduce the time spent and resources. The orthopedist is the initial physician to whom patients with neuromuscular symptoms are seen in the majority of cases. Neurologists seem to be more familiar with neuromuscular symptoms and diseases.

Electrodiagnostic consultations in Zambia: Referral characteristics and neuromuscular disorders

IntroductionResearch on neuromuscular disorders in sub-Saharan Africa is scarce. We aimed to delineate referral characteristics and the neuromuscular disorders observed among electrodiagnostic (EDX) consultations in a tertiary care setting in Zambia. MethodsEDX records were reviewed for all specialist-performed studies after the establishment of the laboratory. The frequency of demographic, medical characteristics, and final EDX impressions are presented. ResultsAmong 108 referrals, 52% were male, 84% were adults (mean age 44 years). Referrals were predominantly outpatients (85%) and sent by neurologists (68%). HIV infection was common (12%). Diabetes was rare (3%). Overall, 77% of studies were abnormal. Polyneuropathy was the most common abnormal EDX finding, followed by motor neuron disease. DiscussionA diverse range of neuromuscular diseases was evaluated among EDX referrals in Zambia. Though labor and expertise intensive, access to EDX consultation can enhance clinical care and facilitate research and surveillance of neuromuscular disorders in the region.

Diagnosis and Prognosis of Carpal Tunnel Syndrome

Carpal tunnel syndrome is the most common entrapment neuropathy seen in the electrodiagnostic laboratory. Clinical assessment is an important part of the electrodiagnostic consultation and helps to form an appropriate differential diagnosis. Sensory conduction studies are a critical part of the evaluation. Using a summary index, such as the combined sensory index, is preferable to considering single tests. Motor conduction studies are also important as they will detect isolated compression of motor branches or fascicles. Needle EMG is useful to detect axon loss as well as to evaluate for other peripheral nervous system sites of impairment. The electrodiagnostic examination can also impart information about the likelihood of success after carpal tunnel release.

Electrodiagnostic consultation and identification of neuromuscular conditions in persons with diabetes

Although the American Association of Neuromuscular and Electrodiagnostic Medicine recommends that electrodiagnostic procedures should be performed by physicians with specialty training, these procedures are increasingly being performed by non-specialists. We used a nationally representative sample of Medicare beneficiaries with diabetes who used electrodiagnostic services in 2006 to examine whether specialists and non-specialists were different in the rates of identifying common neuromuscular conditions. Specialists (neurologists and physiatrists) performed 62% of electrodiagnostic consultations; non-specialist physicians and non-physicians performed 31% and 5%, respectively. After adjusting for age, race/ethnicity, diabetes severity, and comorbidities, specialists were 1.26-9 times more likely than non-physicians to diagnose polyneuropathy, lumbosacral radiculopathy, cervical radiculopathy, carpal tunnel syndrome, and ulnar neuropathy. Almost 80% of electrodiagnostic studies performed by specialists included electromyography testing; fewer than 13% by non-specialists did. Inadequate use of electromyography and fewer specific diagnoses suggest that many non-specialists perform insufficiently comprehensive electrodiagnostic studies.

PO5.6 Pancoast Tumor as a Cause of Profound Brachial Plexopathy

59-year-old right-handed policeman had an aching pain of the right shoulder region with some radiation to the arm, forearm and hand and developed numbness of the right hand later. He came to the orthopaedist and was diagnosed with cervical spondylosis with radiculopathy. He was treated with nonsteroidal anti-inflammatory medication and vitamin B. However, his symptoms did not improve and one month later he developed weakness of right upper extremity. Because his symptoms still had not abated, he returned to his physician who referred him to see a neurologist later. The neurologist diagnosed him with right brachial plexopathy and gave a referral to physiatrist for an electrodiagnostic consultation. Upon further questioning during this interview the patient stated that he had poor appetite and had lost about 15 kilograms in three months. He had no underlying disease, and had no trauma or surgery before his symptoms occurred. Nevertheless, he was a heavy smoker (two packs per day) for thirty years and had drunk alcohol (about one bottle per day) for forty years. Physically the patient looked sick and cachexia. His blood pressure was 120/85 mmHg, body temperature was 36.4 degree celcius, pulse rate was 85 beats/minute and respiratory rate was 28 times/minute. Horner’s syndrome was detected and the right supraclavicular lymph node could be palpated. He complained of a severe amount of a dull aching pain, primarily during attempts to move the affected shoulder and arm. Full passive Pancoast Tumor as a Cause of Profound Brachial Plexopathy

The Clinician Effect on “Objective” Technical Components of the Electrodiagnostic Consultation

To examine the impact of clinician factors on technical data within an electrodiagnostic consultation for low-back pain and spinal stenosis. Examiner differences on single-segment paraspinal mapping scores and other findings were examined in a prospective, masked, double-controlled trial involving 150 people aged 55-80 yrs who were selected for no symptoms, back pain, or possible spinal stenosis. Unmasked clinicians were more variable than masked physicians (F2,219 = 4.808, P =or<0.01) and gave lower scores to people they felt had mechanical back pain. The percentage of inadequate segmental scores differed among clinicians (0-16.6%, F8,226 = 4.170, P < 0.001), with fellows having more difficulty than faculty (11.76 +/- 32.38% vs. 0.75 +/- 8.67%) (t233 = 3.753, P < 0.001). Correction of clinician bias improved the relationship between paraspinal score and subjects' ability to walk (weighted regression R = 0.129, B = -0.047, P < 0.001; unweighted regression R = 0.090, B = -0.045, P < 0.001). Objective testing is adversely affected by clinician factors including prejudgment, experience, and individual idiosyncrasies. Less variation is found in more codified procedures. For electrodiagnostic consultation, correction of variability improves the relationship of test results to disability.

Carpal tunnel syndrome and manual milking: nerve conduction studies in 43 cases

From 1989 to 2004, 3125 consecutive patients had electrodiagnosis of carpal tunnel syndrome (CTS); from these 43 cases (1.38%) were associated to manual milking; mean age was 44.9 years and 88.4% were male. The mean time in the milking profession was 247 months; the mean daily milking time was 146 minutes; symptoms referred at electrodiagnostic consultation had lasted on average 34 months, 83% were bilateral. The median sensory nerve conduction study was abnormal in 75.6% to the right and 66.7% to the left hand. The median nerve motor distal latency (MDL) was abnormal in 92.1% to the right and in 80.0% to the left hand. There were no differences between right and left for all electrophysiological parameters. In CTS related to manual milking most cases were men, with the MDL more affected than the sensory distal latencies and the electrophysiological abnormalities were found to be symmetric. Manual milking could be a natural model for occupational CTS. In contrast to idiopathic CTS, there was a greater involvement of motor fascicles; this finding is remarkable for CTS.

P09.1 Problems in electrodiagnostic consultation in a patient with HIV infection: A case report

P09.1 Problems in electrodiagnostic consultation in a patient with HIV infection: A case report

Spinal Stenosis, Back Pain, or No Symptoms at All? A Masked Study Comparing Radiologic and Electrodiagnostic Diagnoses to the Clinical Impression

Haig AJ, Tong HC, Yamakawa KS, Quint DJ, Hoff JT, Chiodo A, Miner JA, Choksi VR, Geisser ME, Parres CM. Spinal stenosis, back pain, or no symptoms at all? A masked study comparing radiologic and electrodiagnostic diagnoses to the clinical impression. Objective To assess the relations between clinically recognized lumbar spinal stenosis and the conclusions of masked radiologists and electrodiagnosticians. Design Prospective, masked, double-controlled trial. Setting University spine center. Participants One hundred fifty persons age 55 to 80 years with or without back pain and with or without magnetic resonance imaging (MRI)–demonstrated stenosis, screened for neuropathy risk, previous surgery, or cancer. Interventions Questionnaires on pain and function; ambulation testing and physical examination; and masked electrodiagnotics and MRI. Main Outcome Measure Diagnostic impressions of the examining clinician, radiologist, and electrodiagnostician. Results Following application of post hoc exclusion criteria and elimination of patients due to incomplete or inadequate test data, the clinical diagnosis was lumbar stenosis in 50 subjects, back pain in 44 subjects, and no pain in 32 subjects. Radiologic and clinical impression had no relation ( P=.80 vs asymptomatic, P=.99 vs back pain controls). Electrodiagnostic impression trended to relate to clinical impression ( P=.14 vs asymptomatic, P=.09 vs back pain). Retrospective application of age-related electrodiagnostic norms for paraspinal electromyographic and limb motor unit changes, established in this study, reclassified 13 of the 17 asymptomatic persons whom the electrodiagnostician thought had stenosis. The clinical impression did correspond to history and physical examination findings typically associated with spinal stenosis and to the independent impression of a neurosurgeon who examined MRI and clinical, but not to the electrodiagnostic data. Conclusions The impression obtained from an MRI scan does not determine whether lumbar stenosis is a cause of pain. Electrodiagnostic consultation may be useful, especially if age-related norms obtained in this study are applied.

The Sensitivity and Specificity of Electrodiagnostic Testing for the Clinical Syndrome of Lumbar Spinal Stenosis

Prospective, masked, double controlled diagnostic trial. To determine the sensitivity and specificity of electrodiagnostic consultation (EDX) for the clinical syndrome of lumbar spinal stenosis. EDX has been used for more than 50 years to diagnose spinal disorders but has not met the new standards of evidence-based medicine. A total of 150 subjects (asymptomatic volunteers and patients with MRIs suggesting back pain or spinal stenosis; 55-80 years of age) underwent physiatrist history and physical examination, MRI, and review of this data by a neurosurgeon, with each clinician masked to any outside information, leading to a unanimous consensus on diagnosis in 55. After masked EDX testing, 7 subjects with undiagnosed neuromuscular disease were discovered. EDX findings were related to "clinical gold standard" diagnoses in 48 persons. Paraspinal mapping EMG score of >4 had 100% specificity and 30% sensitivity for stenosis compared with either the back pain or asymptomatic groups (each, P < 0.04). A composite limb and paraspinal fibrillation score had a sensitivity of 47.8% and specificity of 87.5% (P = 0.008), and H-wave sensitivity was 36.4, specificity 91.3 (P = 0.026) for stenosis versus all controls. This first masked study in the 60-year history of needle electromyography also introduces anatomically validated needle placement, quantified and reproducible examination of the paraspinal muscles, and dual control populations to EDX research in spinal disorders. EDX has statistically significant, clinically meaningful specificity for spinal stenosis and detects neuromuscular diseases that may masquerade as stenosis.

What good is EMG to the patient and practitioner?

Electromyography (EMG) and nerve conduction studies (NCS) are not only tests to be performed in isolation and reported without consideration of the clinical context, but rather form part of what has been referred to as the electrodiagnostic consultation. Using all of the pertinent information available to the electromyographer performing the test, the electrodiagnostic consultation strives toward the goal of helping the patient and the referring physician to establish a correct diagnosis. Although not without limitations, EMG as an extension of the clinical history and physical examination can be a powerful and sensitive diagnostic tool. Like any tool, however, the final result depends on the skill and expertise with which it is wielded.

The value of electrodiagnostic consultation for patients with upper extremity nerve complaints: a prospective comparison with the history and physical examination

Objectives: To determine whether electrodiagnostic testing changes diagnostic certainty compared with a detailed history and physical examination, and whether interactions between medical information, the extent of testing, and diagnostic certainty imply a need for advanced medical knowledge on the part of the tester. Design: Prospective observation. Setting: University orthopedic department and small community hospital electrodiagnostic laboratories. Patients: Two hundred fifty-five consecutive referrals for upper extremity nerve complaints. Outcome Measures: Diagnosis, diagnostic confidence, and severity of neurologic lesion were coded after standardized history and physical and after electrodiagnostic testing. Results: Electrodiagnostic testing substantially altered 42% of diagnoses, confirmed 37%, and did not clarify 21%. The extent of testing correlated with the size of the differential diagnosis, the number of previous hospitalizations, and the number of other medical problems. Confidence in final diagnoses correlated positively with severity of the lesion, but negatively with the size of the differential diagnosis and the number of painful body areas. Hospitalizations and medical problems also tended towards negative correlations. Conclusions: This study, in which all electrodiagnostics, histories, and physical examinations were performed by a single physician, suggests that electrodiagnosis substantially alters clinical impressions in a large percentage of patients. The complex relationship between clinical information, the extent of testing, and final diagnostic certainty suggests that specialized medical knowledge is required for accurate electrodiagnosis.