Assessment of Central Motor Conduction Time in the Diagnosis of Compressive Thoracic Myelopathy

Nakanishi, Kazuyoshi; Tanaka, Nobuhiro; Sasaki, Hirofumi; Kamei, Naosuke; Hamasaki, Takahiko; Yamada, Kiyotaka; Yamamoto, Risako; Nakamae, Toshio; Ochi, Mitsuo

doi:10.1097/brs.0b013e3181d9e7a4

Cited by 22 publications

(27 citation statements)

References 40 publications

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“…[2][3][4]8,9 The CMCT calculated by subtracting the F-wave latencies from the latencies measured to ADM after transcranial stimulation are slightly shorter than that obtained after magnetic root stimulation. 4 This difference is due to the fact that the F-wave represents the latency to the alpha motor neuron, whereas the site of magnetic root excitation is separate to that of the spinal root exit.…”

Section: Discussionmentioning

confidence: 99%

“…However, there are few studies regarding the normal values of CMCT. [1][2][3][4] The conduction time for the corticospinal tract is believed to be affected by body height, since it is dependent on the length of the conduction pathway. It is unclear whether normal values of CMCT can be adapted to people of different heights, or whether aging affects the conduction time for the corticospinal tract; to our knowledge, no studies have reported age or height correlations with CMCT.…”

Section: Introductionmentioning

confidence: 99%

“…21 Some authors reported that measurement of CMCT was valuable for diagnosis of CCM and CTM. 2,3,22 CCM consists of cervical spondylotic myelopathy (CSM), ossification of the posterior longitudinal ligament (OPLL), and other degenerative disease. Some authors have reported that most patients with CSM were in their sixth and seventh decades by the time of surgery.…”

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confidence: 99%

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Effects of differences in age and body height on normal values of central motor conduction time determined by F-waves

Imajo

Kanchiku

Suzuki

et al. 2015

The Journal of Spinal Cord Medicine

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Objectives: To investigate the effect on central motor conduction time (CMCT) based on the relationship between age and height in normal subjects. Design: Retrospective study. Methods: One hundred and ninety nine normal subjects (107 men and 92 women; mean age 39.0 ± 16.4 years; mean height 164.5 ± 8.8 cm) participated in the study. The approximate ages of subjects were as follows: 82 (20-29 years old), 32 (30-39 years old), 32 (40-49 years old), 28 (50-59 years old), and 25 (≧60 years old). The heights of 9, 49, 79, 53, and 9 subjects were <150 cm, 150-160 cm, 160-170 cm, 170-180 cm, and >180 cm, respectively. CMCT-abductor digiti minimi (ADM) and abductor hallucis (AH) were calculated by subtracting the peripheral motor conduction time (PMCT) from the onset latency of motor evoked potentials (MEPs) evoked by transcranial magnetic stimulation. PMCT was calculated from the latencies of the compound muscle action potentials (CMAPs) and F-waves as follows: (latency of CMAPs + latency of F-waves -1)/2. Outcome measures: CMCT-ADM and CMCT-AH. Results:The normative values were 5.2 ± 0.8 ms and 11.8 ± 1.3 ms for CMCT-ADM and CMCT-AH, respectively. CMCT-ADM was not significantly correlated with age (P = 0.196) and body height (P = 0.158). CMCT-AH had significantly positive, linear correlations with age and body height (CMCT-AH = 0.014 × age + 10.971, P = 0.011, R = 0.179 and CMCT-AH = 0.026 × body height + 7.158, P = 0.010, R = 0.182). Conclusions: We suggest normative values of 3.2-7.2 ms in CMCT-ADM for subjects exerting slight effort on ADM regardless age and body height. CMCT-AH had significantly positive, linear correlations with age and body height.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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confidence: 99%

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Effects of differences in age and body height on normal values of central motor conduction time determined by F-waves

Imajo

Kanchiku

Suzuki

et al. 2015

The Journal of Spinal Cord Medicine

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“…12 They reported that the causes of deterioration were axial spread of ossification of the posterior longitudinal ligament, other spinal lesions, cerebral infarction, and peripheral neuropathy. Central motor conduction time measurements are also a useful tool for detecting functional deterioration of the motor pathway due to thoracic spinal cord compression 24 or cerebral infarction, 27,31 and the F-wave study can detect a peripheral neuropathy. 14,16,26 Consequently, our data should provide important information when a reduced JOA score following surgery is observed and those electrophysiological screenings are implemented, because our study utilized a simple clinical model of cervical myelopathy.…”

Section: Discussionmentioning

confidence: 99%

Electrophysiological evidence of functional improvement in the corticospinal tract after laminoplasty in patients with cervical compressive myelopathy

Nakanishi¹,

Tanaka²,

Kamei³

et al. 2014

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Object Cervical laminoplasty is a surgical procedure for cervical compressive myelopathy (CCM), and satisfactory outcomes have been reported. However, few reports have examined the pathophysiology of improvements in spinal cord function. The aim of this study was to investigate the variation in central motor conduction time (CMCT) before and after cervical laminoplasty in patients with CCM. Methods Motor evoked potentials (MEPs) following transcranial magnetic stimulation and compound muscle action potentials (CMAPs) and F-waves following electrical stimulation of the ulnar and tibial nerves at the wrist and ankle were measured from the abductor digiti minimi muscle (ADM) and abductor hallucis muscle (AH) in 42 patients with CCM before and 1 year after cervical laminoplasty. The peripheral conduction time (PCT) was calculated as follows: (latency of CMAPs + latency of F-waves − 1)/2. The CMCT was calculated by subtracting the PCT from the onset latency of the MEPs. The CMCT recovery ratio was defined and calculated as the ratio of CMCT values 1 year after surgery to those before surgery. The CMCT data were analyzed as longer or shorter CMCT between the patients' right and left ADMs and AHs. The Japanese Orthopaedic Association (JOA) score for cervical myelopathy was obtained as a clinical outcome before and 1 year after surgery. The recovery rate (RR) 1 year after surgery was calculated using the following formula: (postoperative JOA score 1 year after surgery – preoperative JOA score)/(17 – preoperative JOA score) × 100. Correlations among CMCT parameters, patient age, JOA score, and RR were determined. Results The longer and shorter CMCTs from the ADM (longer, p = 0.000; shorter, p = 0.008) and the longer CMCT from the AH (longer, p = 0.000) before surgery decreased significantly 1 year after surgery; the shorter CMCT from the AH did not significantly differ (shorter, p = 0.078). The mean JOA score before surgery was 10.1 ± 3.0 and improved significantly to 12.9 ± 2.7 at 1 year after surgery (p = 0.000). The mean CMCT recovery ratio and RR were 0.91 ± 0.18 and 0.43 ± 0.27, respectively. The longer/shorter CMCT parameters in the ADM and AH before or 1 year after surgery correlated significantly with the JOA score both before and 1 year after surgery. The CMCT recovery ratio from the longer CMCT in the ADM correlated significantly with the RR (r = − 3090, p = 0.011). There were no significant correlations between age and any CMCT parameters or CMCT recovery ratios. Conclusions These results suggest that cervical laminoplasty improves corticospinal tract function 1 year after surgery, which may be one of the reasons for the JOA score improvements in patients with CCM. The degree of improvement in corticospinal tract function did not correlate with patient age in this case series. The results demonstrated quantitative evidence of the pathophysiology of functional recovery in the corticospinal tract following cervical laminoplasty in patients with CCM.

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“…CMCT was determined as described previously 29,30,32 and was measured for all patients before surgery. Surface recording electrodes were placed bilaterally on the abductor digiti minimi muscle (ADM) and abductor hallucis muscle (AH) using the standard belly-tendon method.…”

Section: Electrophysiological Assessmentsmentioning

confidence: 99%

Electrophysiological assessments of the motor pathway in diabetic patients with compressive cervical myelopathy

Nakanishi¹,

Tanaka²,

Kamei³

et al. 2015

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OBJECT The occurrence of compressive cervical myelopathy (CCM) increases in adults over 50 years of age. In addition, diabetes mellitus (DM) is a frequent comorbidity for people of this age and may impact the severity of CCM. The authors assessed motor pathway function in diabetic patients with CCM to investigate the correlation between electrophysiological parameters and clinical symptoms. METHODS Motor evoked potentials (MEPs) were measured from the abductor digiti minimi muscle (ADM) and the abductor hallucis muscle (AH) following transcranial magnetic stimulation, as were M- and F-waves following electrical stimulation of the ulnar and tibial nerves, in 22 patients with CCM and diabetes mellitus (DM) who had not experienced symptomatic diabetic neuropathy (CCM-DM group), in 92 patients with CCM alone (CCM group), and in 24 healthy adults (control group). The peripheral conduction time (PCT; measured from the ADM and AH) was calculated as follows: (M-wave latency + F-wave latency −1)/2. The central motor conduction time (CMCT; measured from the ADM and AH) was calculated by subtracting the PCT from the onset latency of the MEPs. The Japanese Orthopaedic Association (JOA) score for cervical myelopathy was obtained before and 1 year after surgery as a clinical outcome measure. RESULTS MEP, PCT, and CMCT parameters in the CCM-DM and CCM groups were significantly longer than those in the control group (p = 0.000−0.007). The PCTs in the CCM-DM group were significantly longer than those in the CCM group (p = 0.001−0.003). No significant differences were detected in the MEP and CMCT parameters between the CCM-DM and CCM groups (p = 0.080–1.000). The JOA score before surgery in the CCM-DM group was 10.7 ± 2.0 points and was significantly lower than that in the CCM group (12.2 ± 2.5 points, p = 0.015). In the CCM-DM group, JOA scores before surgery correlated with MEP-AH (r = −0.610, p = 0.012) and PCT-AH (r = −0.676, p = 0.004) values, but not with CMCT values, while the JOA scores were related to both MEP and CMCT parameters in the CCM group. The JOA scores improved to 13.8 ± 2.2 points after surgery (p = 0.001) and correlated with MEP-AH (r = −0.667, p = 0.005) and PCT-AH (r = −0.611, p = 0.012) in the CCM-DM group. CONCLUSIONS The results suggest that MEP, PCT, and CMCT parameters each reveal abnormalities in the upper and lower motor neurons even in patients with DM. The results also show a prolonged PCT in CCM-DM patients, despite having no history of diabetic neuropathy. Corticospinal tract impairments are similar between CCM and CCM-DM patients, while the JOA score of the CCM-DM patients is lower than that in the CCM patients. The JOA score in CCM-DM patients may be influenced by additional impairments in peripheral nerves or other diabetic complications. These electrophysiological studies may be useful for screening motor pathway function for CCM in patients with DM.

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Assessment of Central Motor Conduction Time in the Diagnosis of Compressive Thoracic Myelopathy

Abstract: Our data showed a significant pattern of CMCT parameters and low CMCT-ADM/AH ratios in patients with CTM. The measurement of CMCT is valuable as a noninvasive technique for screening patients with CTM or CCM before magnetic resonance imaging.

Cited by 22 publications

References 40 publications

Effects of differences in age and body height on normal values of central motor conduction time determined by F-waves

Effects of differences in age and body height on normal values of central motor conduction time determined by F-waves

Electrophysiological evidence of functional improvement in the corticospinal tract after laminoplasty in patients with cervical compressive myelopathy

Electrophysiological assessments of the motor pathway in diabetic patients with compressive cervical myelopathy

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