Objective: To determine the diagnostic value of motor evoked potentials (MEPs ) in the diagnosis of lumbosacral cord disorders. Methods: MEPs in 37 patients with sensory and motor deficits in the lower limbs were stud...Objective: To determine the diagnostic value of motor evoked potentials (MEPs ) in the diagnosis of lumbosacral cord disorders. Methods: MEPs in 37 patients with sensory and motor deficits in the lower limbs were studied. MRI demonstrated spinal cord involvement in 10 patients and cauda equina lesions in 27 patients. A double determination of cent ral motor conduction time (CMCT), calculated as the difference between the laten cies of responses evoked by cortical and paravertebral magnetic stimulation and as the difference between the latency of cortical MEP and the total peripheral c onduction time calculated from the F-wave latency, enabled discrimination betw een a delay along the proximal root and a delay along the corticospinal tract. A n abnormality of the CMCT calculated with both techniques is indicative of centr al motor pathway damage, whereas an abnormality of the CMCT calculated from the latency of responses evoked by paravertebral magnetic stimulation associated wit h a normal CMCT calculated from the F-wave latency suggests a cauda equina les ion. Results: Neurophysiologic findings strongly correlated with the lesion site documented by MRI (cauda equina or lumbosacral cord). All patients with MR evid ence of cord involvement had an abnormality of CMCT calculated with both methods , suggesting a lesion of central motor pathways. Clinical examination often fail ed to document a spinal cord lesion, suggesting pure peripheral involvement in 5 of the 10 patients with MR evidence of cord lesion. Conclusion: Motor evoked po tential recording is an accurate and easily applicable test for the diagnosis of lumbosacral spinal cord lesions.展开更多
Early prognostic assessment of obstetrical brachial plexopathies (OBP) would f acilitate rational selection of infants for brachial plexus surgery. We performe d bilateral motor nerve conduction studies (MNCS) of axil...Early prognostic assessment of obstetrical brachial plexopathies (OBP) would f acilitate rational selection of infants for brachial plexus surgery. We performe d bilateral motor nerve conduction studies (MNCS) of axillary, musculocutaneous, radial, median, and ulnar nerves in 33 babies (age 10 60 days) with OBP in ord er to compare the amplitude of compound muscle action potentials (CMAPs). All ba bies were followed up until 6 months of age and the outcome was classified according to muscle strength and arm function. A CMAP a mplitude reduction of more than 90%, compared to the unaffected side, predicted severe weakness of the corresponding root level (p < .0.01). Our results indica te that MNCS are a useful tool for very early prognostic assessment of OBP.展开更多
Evidence of upper motor neuron (UMN) dysfunction is essential in making the diagnosis of amyotrophic lateral sclerosis (ALS). Central motor conduction (CMC) abnormalities detected using transcranial magnetic stimulati...Evidence of upper motor neuron (UMN) dysfunction is essential in making the diagnosis of amyotrophic lateral sclerosis (ALS). Central motor conduction (CMC) abnormalities detected using transcranial magnetic stimulation (TMS) are presumed to reflect UMN dysfunction. CMC is, however, often normal in patients with classical sporadic ALS. The aim of the study was to determine whether the utility of the CMC measure in ALS could be enhanced. We measured CMC to four pairs of muscles (abductor digiti minimi (ADM), biceps, vastus medialis (VM) and abductor hallucis (AH) in 20 controls and 25 ALS patients. The commonest abnormality detected in the ALS patients was an absent MEP, found in 11 patients (44% ) and in 25 of 200 muscles examined. Studying a minimum of three muscles increased the probability of detecting UMN dysfunction. Weakness in the muscle as well as selecting a distal rather than a proximal muscle was significantly associated with an abnormal CMC. Interside differences in CMC were significantly more pronounced in the patient group. In 30% of patients a significant interside difference in AH CMC time was the sole abnormality, suggesting mild UMN dysfunction on the side with the longer CMC.展开更多
文摘Objective: To determine the diagnostic value of motor evoked potentials (MEPs ) in the diagnosis of lumbosacral cord disorders. Methods: MEPs in 37 patients with sensory and motor deficits in the lower limbs were studied. MRI demonstrated spinal cord involvement in 10 patients and cauda equina lesions in 27 patients. A double determination of cent ral motor conduction time (CMCT), calculated as the difference between the laten cies of responses evoked by cortical and paravertebral magnetic stimulation and as the difference between the latency of cortical MEP and the total peripheral c onduction time calculated from the F-wave latency, enabled discrimination betw een a delay along the proximal root and a delay along the corticospinal tract. A n abnormality of the CMCT calculated with both techniques is indicative of centr al motor pathway damage, whereas an abnormality of the CMCT calculated from the latency of responses evoked by paravertebral magnetic stimulation associated wit h a normal CMCT calculated from the F-wave latency suggests a cauda equina les ion. Results: Neurophysiologic findings strongly correlated with the lesion site documented by MRI (cauda equina or lumbosacral cord). All patients with MR evid ence of cord involvement had an abnormality of CMCT calculated with both methods , suggesting a lesion of central motor pathways. Clinical examination often fail ed to document a spinal cord lesion, suggesting pure peripheral involvement in 5 of the 10 patients with MR evidence of cord lesion. Conclusion: Motor evoked po tential recording is an accurate and easily applicable test for the diagnosis of lumbosacral spinal cord lesions.
文摘Early prognostic assessment of obstetrical brachial plexopathies (OBP) would f acilitate rational selection of infants for brachial plexus surgery. We performe d bilateral motor nerve conduction studies (MNCS) of axillary, musculocutaneous, radial, median, and ulnar nerves in 33 babies (age 10 60 days) with OBP in ord er to compare the amplitude of compound muscle action potentials (CMAPs). All ba bies were followed up until 6 months of age and the outcome was classified according to muscle strength and arm function. A CMAP a mplitude reduction of more than 90%, compared to the unaffected side, predicted severe weakness of the corresponding root level (p < .0.01). Our results indica te that MNCS are a useful tool for very early prognostic assessment of OBP.
文摘Evidence of upper motor neuron (UMN) dysfunction is essential in making the diagnosis of amyotrophic lateral sclerosis (ALS). Central motor conduction (CMC) abnormalities detected using transcranial magnetic stimulation (TMS) are presumed to reflect UMN dysfunction. CMC is, however, often normal in patients with classical sporadic ALS. The aim of the study was to determine whether the utility of the CMC measure in ALS could be enhanced. We measured CMC to four pairs of muscles (abductor digiti minimi (ADM), biceps, vastus medialis (VM) and abductor hallucis (AH) in 20 controls and 25 ALS patients. The commonest abnormality detected in the ALS patients was an absent MEP, found in 11 patients (44% ) and in 25 of 200 muscles examined. Studying a minimum of three muscles increased the probability of detecting UMN dysfunction. Weakness in the muscle as well as selecting a distal rather than a proximal muscle was significantly associated with an abnormal CMC. Interside differences in CMC were significantly more pronounced in the patient group. In 30% of patients a significant interside difference in AH CMC time was the sole abnormality, suggesting mild UMN dysfunction on the side with the longer CMC.
