Epicritic Sensation in Cervical Spinal Cord Injury: Diagnostic Gains Beyond Testing Light Touch

Kilohertz-frequency interferential current induces hypoalgesic effects more comfortably than TENS

Recent research on transcutaneous electrical stimulation has shown that inhibiting nerve conduction with a kilohertz frequency is both effective and safe. This study primarily aims to demonstrate the hypoalgesic effect on the tibial nerve using transcutaneous interferential-current nerve inhibition (TINI), which injects the kilohertz frequency produced by the interferential currents. Additionally, the secondary objective was to compare the analgesic effect and comfort of TINI and transcutaneous electrical nerve stimulation (TENS). Thirty-one healthy adults participated in this cross-over repeated measures study. The washout period was set to 24 h or more. Stimulus intensity was set just below the pain threshold level. TINI and TENS were applied for 20 min each. The ankle passive dorsiflexion range of motion, pressure pain threshold (PPT), and tactile threshold were measured at the baseline, pre-test, test (immediately before ceasing intervention), and post-test (30 min after ceasing intervention) sessions. After the interventions, the participants evaluated the level of discomfort for TINI and TENS on a 10 cm visual analog scale (VAS). As the results, PPT significantly increased compared to baseline in test and posttest sessions of TINI, but not in those of TENS. Also, participants reported that TENS was 36% more discomfort than TINI. The hypoalgesic effect was not significantly different between TINI and TENS. In conclusion, we found that TINI inhibited mechanical pain sensitivity and that the inhibitory effect persisted long after electrical stimulation ceased. Our study also shows that TINI provides the hypoalgesic effect more comfortably than TENS.

Development of a Telemedicine Neurological Examination for Spine Surgery: A Pilot Trial

STUDY DESIGN

This was a prospective cohort study.

OBJECTIVE

The objective of this study was to design and test a novel spine neurological examination adapted for telemedicine.

SUMMARY OF BACKGROUND DATA

Telemedicine is a rapidly evolving technology associated with numerous potential benefits for health care, especially in the modern era of value-based care. To date, no studies have assessed whether.

METHODS

Twenty-one healthy controls and 20 patients with cervical or lumbar spinal disease (D) were prospectively enrolled. Each patient underwent a telemedicine neurological examination as well as a traditional in-person neurological examination administered by a fellowship trained spine surgeon and a physiatrist. Both the telemedicine and in-person tests consisted of motor, sensory, and special test components. Scores were compared via univariate analysis and secondary qualitative outcomes, including responses from a satisfaction survey, were obtained upon completion of the trial.

RESULTS

Of the 20 patients in the D group, 9 patients had cervical disease and 11 patients had lumbar disease. Comparing healthy control with the D group, there were no significant differences with respect to all motor scores, most sensory scores, and all special tests. There was a high rate of satisfaction among the cohort with 92.7% of participants feeling "very satisfied" with the overall experience.

CONCLUSIONS

This study presents the development of a viable neurological spine examination adapted for telemedicine. The findings in this study suggest that patients have comparable motor, sensory, and special test scores with telemedicine as with a traditional in-person examination administered by an experienced clinician, as well as reporting a high rate of satisfaction among participants. To our knowledge, this is the first telemedicine neurological examination for spine surgery. Further studies are warranted to validate these findings.

New Method for the Quantitative Assessment of Sensory Disturbances in Cervical Myelopathy: Application for Neurological Level Diagnosis

Introduction

Cervical myelopathy frequently manifests as sensory disturbances, including numbness, and their distribution pattern aids in neurological level diagnosis. However, the objective assessment of sensory disturbances is challenging. In this study, we attempted to quantitatively evaluate sensory symptoms in patients with cervical myelopathy according to lesion level using PainVision^Ⓡ.

Methods

Dermal sensations were evaluated in patients (n = 158) and healthy volunteers (n = 100) using PainVision^Ⓡ PS-2100, which measured the current perception threshold (CPT). The results were analyzed for their correlation with magnetic resonance imaging (MRI) data, visual analog scale (VAS) scores, and patient functional status assessed by the Japanese Orthopaedic Association (JOA) and JOA Cervical Myelopathy Evaluation Questionnaire (JOACMEQ) scores.

Results

Forearm and palm CPT values were significantly higher in patients with cervical myelopathy (both sites, P < 0.001) and were negatively correlated with the JOA score (forearm, r = −0.33; palm, r = −0.35; P < 0.001) and the JOACMEQ scores for upper extremity function (forearm, r = −0.37; palm, r = −0.39; P < 0.001), lower extremity function (forearm, r = −0.39; palm, r = −0.40; P < 0.001), and quality of life (forearm r = −0.27, P = 0.0025); however, no correlation was observed with the VAS score. Stratification of patients according to their lesion levels determined by MRI revealed that the C3/C4 subgroup had significantly higher forearm CPT values than the C4/C5 (P = 0.024) and C5/C6 (P = 0.0013) subgroups and higher palm CPT values than the C5/C6 subgroup (P = 0.009).

Conclusions

Quantitative measurements of sensory disturbances using the PainVision^Ⓡ device correspond to the degree of patient functional disability and the lesion level. This indicates that both the distribution and intensity of sensory abnormalities are important for neurological level diagnosis in patients with cervical myelopathy.

Validation of a novel cone tool for pinprick sensation examination in patients with spinal cord injury

STUDY DESIGN

Psychometrics study.

OBJECTIVE

The objective of this study was to introduce a novel tool for pinprick sensation examination and validate its usefulness in patients with spinal cord injury (SCI).

SETTING

China Rehabilitation Research Center, Capital Medical University School of Rehabilitation Medicine, China.

METHODS

A set of cone tools with different tapers (22.5°, 45°, 67.5°, 90°, 112.5°, 135°, 157.5°, and 180°) was made. The cone tool was validated first in 91 able-bodied individuals and then in 30 patients with SCI. The reliability and validity of the cone tool were analyzed by comparing the results of a pinprick sensation examination with the results of the International Standards for the Neurological Classification of SCI (ISNCSCI), the cone tool, and the thermal analyzer.

RESULTS

The intraclass correlation coefficient (ICC) of the cone tool in able-bodied individuals was between 0.48 and 0.94 while that of the cone tool and the ISNCSCI tool ranged between 0.43 and 0.78. Pinprick sensation in patients with SCI can be graded into five levels using four tapers (22.5°, 45°, 67.5°, and 90°): normal, slight impairment, moderate impairment, severe impairment, and complete loss of sensation.

CONCLUSION

This easy-to-use cone tool can produce a reliable semi-quantitative pinprick test result and is useful for pinprick sensation examination in patients with SCI.

Technical development of transcutaneous electrical nerve inhibition using medium-frequency alternating current

Background

Innovative technical approaches to controlling undesired sensory and motor activity, such as hyperalgesia or spasticity, may contribute to rehabilitation techniques for improving neural plasticity in patients with neurologic disorders. To date, transcutaneous electrical stimulation has used low frequency pulsed currents for sensory inhibition and muscle activation. Yet, few studies have attempted to achieve motor nerve inhibition using transcutaneous electrical stimulation. This study aimed to develop a technique for transcutaneous electrical nerve inhibition (TENI) using medium-frequency alternating current (MFAC) to suppress both sensory and motor nerve activity in humans.

Methods

Surface electrodes were affixed to the skin of eight young adults to stimulate the median nerve. Stimulation intensity was increased up to 50% and 100% of the pain threshold. To identify changes in sensory perception by transcutaneous MFAC (tMFAC) stimulation, we examined tactile and pressure pain thresholds in the index and middle fingers before and after stimulation at 10 kHz. To demonstrate the effect of tMFAC stimulation on motor inhibition, stimulation was applied while participants produced flexion forces with the index and middle fingers at target forces (50% and 90% of MVC, maximum voluntary contraction).

Results

tMFAC stimulation intensity significantly increased tactile and pressure pain thresholds, indicating decreased sensory perception. During the force production task, tMFAC stimulation with the maximum intensity immediately reduced finger forces by ~ 40%. Finger forces recovered immediately after stimulation cessation. The effect on motor inhibition was greater with the higher target force (90% MVC) than with the lower target (50% MVC). Also, higher tMFAC stimulation intensity provided a greater inhibition effect on both sensory and motor nerve activity.

Conclusion

We found that tMFAC stimulation immediately inhibits sensory and motor activity. This pre-clinical study demonstrates a novel technique for TENI using MFAC stimulation and showed that it can effectively inhibit both sensory perception and motor activity. The proposed technique can be combined with existing rehabilitation devices (e.g., a robotic exoskeleton) to inhibit undesired sensorimotor activities and to accelerate recovery after neurologic injury.

Predictive Value of Upper Limb Muscles and Grasp Patterns on Functional Outcome in Cervical Spinal Cord Injury

Objective. To determine which single or combined upper limb muscles as defined by the International Standards for the Neurological Classification of Spinal Cord Injury (ISNCSCI); upper extremity motor score (UEMS) and the Graded Redefined Assessment of Strength, Sensibility, and Prehension (GRASSP), best predict upper limb function and independence in activities of daily living (ADLs) and to assess the predictive value of qualitative grasp movements (QlG) on upper limb function in individuals with acute tetraplegia. Method. As part of a Europe-wide, prospective, longitudinal, multicenter study ISNCSCI, GRASSP, and Spinal Cord Independence Measure (SCIM III) scores were recorded at 1 and 6 months after SCI. For prediction of upper limb function and ADLs, a logistic regression model and unbiased recursive partitioning conditional inference tree (URP-CTREE) were used. Results. Logistic regression and URP-CTREE revealed that a combination of ISNCSCI and GRASSP muscles (to a maximum of 4) demonstrated the best prediction (specificity and sensitivity ranged from 81.8% to 96.0%) of upper limb function and identified homogenous outcome cohorts at 6 months. The URP-CTREE model with the QlG predictors for upper limb function showed similar results. Conclusion. Prediction of upper limb function can be achieved through a combination of defined, specific upper limb muscles assessed in the ISNCSCI and GRASSP. A combination of a limited number of proximal and distal muscles along with an assessment of grasping movements can be applied for clinical decision making for rehabilitation interventions and clinical trials.

Changes in Strength, Sensation, and Prehension in Acute Cervical Spinal Cord Injury

Objective. To investigate the internal and external responsiveness and recovery profiles of the Graded Redefined Assessment of Strength, Sensibility, and Prehension (GRASSP) instrument in revealing changes in upper limb function within the first year following cervical spinal cord injury (SCI). Method. A European prospective, longitudinal, multicenter study assessing the GRASSP at 1, 3, 6, and 12 months after cervical SCI. Subtests of GRASSP were compared to the upper extremity motor (UEMS) and light touch scores (LT) according to the International Standards of Neurological Classification of Spinal Cord Injury (ISNCSCI), the Spinal Cord Independence Measure self-care subscore (SCIM-SS), as well as a clinician-rated outcome measure (CROM) of clinical relevance. Data were analyzed for GRASSP responsiveness and recovery rate over time. Results. Seventy-four participants entered the study. GRASSP subtests proved responsive (standardized response mean [SRM] ranged from 0.79 to 1.48 for strength, 0.50 to 1.03 for prehension, and 0.14 to 0.64 for sensation) between all examination time points. In comparison, UEMS and LT showed lower responsiveness (SRM UEMS ranged from 0.69 to 1.29 and SRM LT ranged from 0.30 to −0.13). All GRASSP subtests revealed significant, moderate-to-excellent correlations with UEMS, LT, and SCIM-SS at each time point, and changes in GRASSP subtests were in accordance with the CROM. GRASSP prehension and motor recovery was largest between 1 and 3 months. Conclusion. The GRASSP showed excellent responsiveness, detecting distinct changes in strength and prehension relating to the severity of cervical SCI. It detected clinically significant changes complimentary to the ISNCSCI and SCIM-SS assessments.

Outcome of the upper limb in cervical spinal cord injury: Profiles of recovery and insights for clinical studies

BACKGROUND

Improved appreciation of recovery profiles of sensory and motor function as well as complex motor functions (prehension) after cervical spinal cord injury (SCI) will be essential to inform clinical studies to consider primary and secondary outcome measures for interventions and the optimization of dosing and timing of therapies in acute and chronic SCI.

OBJECTIVES

(1) To define the sensory, motor, and prehension recovery profiles of the upper limb and hand in acute cervical SCI and (2) to confirm the impact of AIS severity and conversion on upper limb sensorimotor recovery.

METHODS

An observational longitudinal cohort study consisting of serial testing of 53 patients with acute cervical SCI was conducted. International Standards of Neurological Classification of Spinal Cord Injury, Graded Redefined Assessment of Strength Sensibility and Prehension (GRASSP), Capabilities of Upper Extremity (CUE-Q) Questionnaire, and Spinal Cord Independence Measure III (SCIM-III) were administered at 0-10 days, 1, 3, 6, and 12 months.

ANALYSIS

Change over time was plotted using mean and standard deviation of the total and subgroups of the sample.

RESULTS

Individuals with traumatic tetraplegia show distinct patterns of recovery. Factors that distinguish homogeneous subgroups of the sample are: severity of injury (level of injury, completeness) at baseline and conversion from a complete to an incomplete injury.

CONCLUSIONS

In cervical SCI, clinical recovery can be assessed using standardized measures that distinguish levels of activity and impairment. Specific recovery profiles of the upper limb over the 1-year timecourse provide new insights and opportunity for combined analysis of recovery profiles for different clinical assessment tools of upper limb function which are meaningful to inform the design of study protocols.