Paula Micklesen

Predictive value of somatosensory evoked potentials for awakening from coma.

ObjectivesA systematic review of somatosensory evoked potentials performed early after onset of coma, to predict the likelihood of nonawakening. The pooled results were evaluated for rates of awakening, confidence intervals, and the possibility of rare exceptions. Data SourcesForty-one articles reporting somatosensory evoked potentials in comatose patients and subsequent outcomes, from 1983 to 2000. Study SelectionStudies were included if they reported coma etiology, age group, presence or absence of somatosensory evoked potentials, and coma outcomes. Data ExtractionWe separated patients into four groups: adults with hypoxic-ischemic encephalopathy, adults with intracranial hemorrhage, adults and adolescents with traumatic brain injury, and children and adolescents with any etiologies. Somatosensory evoked potentials were categorized as normal, abnormal, or bilaterally absent. Outcomes were categorized as persistent vegetative state or death vs. awakening. Data SynthesisFor each somatosensory evoked potential result, rates of awakening (95% confidence interval) were calculated: adult hypoxic-ischemic encephalopathy: absent 0% (0%–1%), abnormal 22% (17%–26%), normal 52% (48%–56%); adult intracranial hemorrhage: absent 1% (0%–4%), present 38% (27%–48%); adult-teen traumatic brain injury: absent 5% (2%–7%), abnormal 70% (64%–75%), normal 89% (85%–92%); child-teen: absent 7% (4%–10%), abnormal 69% (61%–77%), normal 86% (80%–92%). ConclusionsSomatosensory evoked potential results predict the likelihood of nonawakening from coma with a high level of certainty. Adults in coma from hypoxic-ischemic encephalopathy with absent somatosensory evoked potential responses have <1% chance of awakening.

Lower extremity manifestations of spasticity in chronic spinal cord injury

The prevalence of various manifestations of spasticity from questionnaire responses and from clinical examination of chronic spinal cord injured patients is reported. Extensor spasms, flexor withdrawal spasms, and clonus were reported by most subjects. Those with incomplete lesions reported more interference with activities, more pain, and less functional usefulness, than did those with complete lesions. Extensor spasms were reported to interfere more with transfers, whereas flexor withdrawal spasms were reported to be more frequent at night and to interfere more with sleep. Increased muscle tone was observed more often in extensor than in flexor muscles. Those with incomplete lesions had more hypertonus and more limited passive joint movements than did those with complete lesions. Flexor withdrawal reactions and extensor spasms were also more pronounced in those with incomplete lesions, particularly those with Frankel grade C lesions.

Prognostic values of electrodiagnostic studies in traumatic radial neuropathy

It is important to have strong predictors of outcome in traumatic neuropathies so that appropriate management can be instituted early. Our objective in this study was to evaluate the prognostic value of electrodiagnostic studies in traumatic radial neuropathy. In this retrospective study, 33 of 67 subjects with traumatic radial neuropathy met the inclusion criteria. Good outcome was defined as grade 3 or higher strength on the Medical Research Council scale in wrist extensors. Compound muscle action potential (CMAP) responses from extensor indicis proprius (EIP) predicted prognosis: 92% of subjects with a recordable CMAP had a good outcome; and 65% of those with an absent response had a good outcome. Recruitment in brachioradialis was also predictive: 92% of those with full, central, or reduced recruitment had a good outcome; 67% of those with discrete recruitment had a good outcome; and only 33% of those with absent recruitment had a good outcome. Studies performed more than 3 months after injury produced more prognostic certainty than those performed earlier. We conclude that electrodiagnostic studies produce useful prognostic information in traumatic radial neuropathy. It is noteworthy, however, that 65% of subjects with an absent radial CMAP (suggesting complete or nearly complete axon loss) still have a good outcome. Muscle Nerve, 2007

Predicting recovery after fibular nerve injury: which electrodiagnostic features are most useful?

Derr JJ, Micklesen PJ, Robinson LR: Predicting recovery after fibular nerve injury: Which electrodiagnostic features are most useful? Objective:Although it is important to have strong predictors of outcome in peripheral mononeuropathies so that appropriate management can be instituted early, little is known about the prognostic value of electrodiagnostic results for these lesions. Our objective in this study was to evaluate the prognostic value of electrodiagnostic studies in fibular neuropathy. Design:In this retrospective study, 39 of 138 subjects with fibular neuropathy met the inclusion criteria. Electrodiagnostic results at the time of testing were evaluated for their value in predicting outcome. Good outcome was defined as grade 4 or higher strength on the Medical Research Council Scale in ankle dorsiflexion. Results:Compound muscle action potential responses from extensor digitorum brevis and tibialis anterior predicted prognosis: 81% of subjects with any tibialis anterior response and 94% with any extensor digitorum brevis response had a good outcome vs. those with absent responses (46% and 52%, respectively). Importantly, there was still a high likelihood of good outcome with absent compound muscle action potential responses. Tibialis anterior compound muscle action potential gave additional prognostic information when extensor digitorum brevis response was absent. Recruitment in tibialis anterior was predictive in traumatic cases. All patients with nontraumatic compression had a good outcome. Conclusions:We conclude that electrodiagnostic studies produce useful prognostic information in fibular neuropathy, particularly in traumatic cases.

Electrophysiologic findings in post-traumatic syringomyelia: implications for clinical management.

Traumatic spinal cord injured (SCI) patients may develop pain, new weakness and/or sensory loss due to an enlarging fluid-filled cyst in the spinal cord. The clinical history and physical exam are nonspecific and insensitive, particularly for diagnosing and monitoring recurrent or progressive post-traumatic syringomyelia (PTS). We compare the sensitivity and specificity of three electrodiagnostic tests, median and ulnar F waves, electromagnetic motor evoked potentials (MEP), and needle electromyography, with respect to syrinx by imaging (MRI or CT scan) and neurologic progression on serial clinical exams. Central motor conduction time (CMCT) calculated from scalp and spine MEP was the most sensitive diagnostic test. F waves were less sensitive and less specific than the CMCT, and did not provide evidence of syrinxes in the mid or upper cervical cord. Positive sharp wave and fibrillation potentials were the least sensitive and least specific. The CMCT is a useful adjunct to imaging studies for diagnosing and monitoring PTS.

Association between the EMG self-assessment examination and later ABEM certification.

Hacker H, Micklesen P, King J, Robinson L: Association between the EMG self-assessment examination and later ABEM certification. Am J Phys Med Rehabil 2008;87:221–223.Our objective was to determine whether performance on the American Association of Neuromuscular and Electrodiagnostic Medicine Training Program Self-Assessment Examination (TPSAE) predicts subsequent performance on the American Board of Electrodiagnostic Medicine (ABEM) certification examination. The TPSAE results were closely associated (r = 0.57) with ranking on the ABEM examination. Those with scores <65% on the TPSAE had <50% chance of ABEM certification, whereas those with scores >84% correct had >90% chance of certification. The TPSAE is a useful predictor of later ABEM certification.