Median nerve somatosensory evoked potentials in medical students: Normative data

VSA-3000: A Quantitative Vibration Sensation Testing Device for Patients With Central Nervous System Injury

Objective: To investigate the effect of using Vibration Sensory Analyzer-3000 (VSA-3000) in patients with impaired vibration sensation caused by central nervous system injury.

Design: Prospective observational study.

Setting: A university hospital for the research and clinical practice of rehabilitation.

Subjects: Sixty patients (30 stroke and 30 spinal cord injury) were recruited, aged between 20 and 71 years old, under stable medication.

Interventions: Not applicable.

Main Measure: VSA-3000 threshold test, tuning fork test and somatosensory evoked potential (SSEP) measurement.

Results: Test-retest reliability was determined based on data collected from 60 subjects, and the intraclass correlation coefficient (ICC) for vibration perception thresholds (VPTs) was in the “substantial” range. The kappa value between VSA-3000 and SSEP was 0.877, which was higher than that of tuning fork (κ = 0.732). VSA-3000 had good diagnostic accuracy with a sensitivity of 94.8%, specificity of 92.9%, and positive-predictive value of 93.8% and negative-predictive value of 94.0%, each value was higher than that of tuning fork. The area under the receiver operating characteristic curve (AUC) of VSA-3000 was 0.95 (95% CI: 0.91 to 0.98) and that of tuning fork was 0.89 (95% CI: 0.85 to 0.95), and there was a significant difference between the two values (P = 0.0216). The types of injury and age were the independent correlates of the VPTs.

Conclusion: The present study provides preliminary evidence that VSA-3000 is a non-invasive and convenient quantitative testing instrument with good diagnostic accuracy, and it may be useful as a screening tool for assessing impaired vibration sensation caused by central nerve injury.

Central nervous system impairment detected by somatosensory evoked potentials in patients with Charcot-Marie-Tooth disease type 1A

Diseases related to peripheral myelin protein 22 (PMP22) have been implicated to involve the central nervous system (CNS). This study aimed to detect central nerve impairment using somatosensory evoked potentials (SSEPs) in patients with Charcot-Marie-Tooth disease (CMT) 1A. A total of 30 CMT1A patients and 26 healthy volunteers were included. Baseline characteristics, brain MRI and segmental SSEPs were collected from the participants. The peak latencies of N9, N13 and N20 were recorded, and central conduction velocity (CCT) was calculated and compared between groups. Significant differences were found in the peak latencies and amplitudes of N9, N13 and N20 between the two groups. CCT was significantly prolonged in the CMT group (7.05 ± 2.09 ms) compared to the control group (5.40 ± 1.79 ms) (p = 0.003). Six of 30 CMT patients had abnormal MRI signals, but no correlation with CCT was found. The central somatosensory pathway that carries SSEPs was impaired in CMT1A patients, which implies an important underlying role of PMP22 in the CNS.

Factors Associated With Inadequate Intraoperative Baseline Lower Extremity Somatosensory Evoked Potentials

PURPOSE

Intraoperative neurophysiologic monitoring involves the use of various modalities, including somatosensory evoked potentials (SEP), to assess the integrity of the at-risk nervous system during surgeries. Reliable baseline tracings are important because they are data against which future tracings are compared to detect potential injury. In some cases, adequate baselines may be difficult to achieve. Therefore, we analyzed several patient-specific factors to determine which variables are associated with inadequate intraoperative SEP baseline signals.

METHODS

This is a single-center, retrospective chart review of 631 consecutive patients who underwent spine or cranial surgeries between 2010 and 2011. Variables analyzed included age, glucose levels, diabetes mellitus type 2, hypertension, hyperlipidemia, height, weight, sex, smoking, preexisting neurologic conditions, surgical history, lower extremity edema, and neurologic examination findings. Association between these patient factors and baseline lower extremity SEP signals were analyzed.

RESULTS

Height, weight, neurologic deficits, lower extremity edema, and history of neurologic disease are each associated with inadequate baseline lower extremity SEPs after controlling for confounding variables. Baseline signals were able to be acquired in 94.1% of patients.

CONCLUSIONS

Adequate baselines are paramount for successful intraoperative neurophysiologic monitoring. However, certain patient-specific factors are associated with inadequate baseline SEP signals. Physical examination findings and a detailed chart review can be done to identify these factors and guide expectations during monitoring. Further research related to patient-specific factors amenable to modification can further improve our capacity to protect the nervous system during surgery.

Applications of pain-related evoked potentials and short-latency somatosensory evoked potentials in acupuncture research: a narrative review

OBJECTIVE

To review and discuss the Chinese and English literature on the use of pain-related evoked potentials (PREP) and short-latency somatosensory EP (SLSEP) in acupuncture research.

METHODS

China National Knowledge Infrastructure Database and MEDLINE were searched for the following key words: acupuncture and PREP or SLSEP.

RESULTS

Thirty-seven articles were included in the review. Researchers usually use PREPs to study the analgesic effect of acupuncture, observe influential factors, or for mechanistic exploration. In the SLSEP studies, researchers focused on response characteristics of acupuncture, acupoint specificity, and influential factors of the treatment. There were some problems with the study design and conclusions.

CONCLUSION

Researchers could use PREP and SLSEP to objectively validate the effects of acupuncture and explore its mechanisms using nerve electrophysiology. Further studies can benefit from observing more acupoints' effects using PREPs or SLSEPs and investigating the placebo effect of acupuncture.