Current Perception Threshold Measurement Research Articles

Long-term dopamine agonist treatment fails to restore altered central sensory processing in restless legs syndrome: Evidence from current perception threshold measurements

ObjectivesAlthough some studies have examined the impact of short-term dopamine agonist treatment on altered central sensory processing in patients with restless legs syndrome (RLS), there is a scarcity of research investigating the effect of long-term treatment with these drugs. The aim of this study is to investigate the long-term impact of dopamine agonist treatment on altered central sensory processing in RLS patients using current perception threshold (CPT) testing. MethodsWe conducted a study of 24 RLS patients, measuring their CPT values before and after dopamine agonist treatment for at least 2 months. Patients were classified as responders or non-responders based on their decrease in International Restless Legs Syndrome (IRLS) score. Clinical parameters were collected and compared pre- and post-treatment. ResultsThe mean duration of treatment with dopamine agonist was 13.6 ± 11.0 months. Our results showed that dopamine agonist treatment significantly improved clinical parameters, including the IRLS score, Visual Analogue Scale, and RLS Quality of Life questionnaire. However, CPT values did not show significant changes for all stimulus frequencies after treatment. Furthermore, we did not find any difference in CPT values before and after treatment in both responders and non-responders. ConclusionsOur study demonstrated that long-term treatment with dopamine agonists effectively reduces RLS symptoms, but does not reverse the altered central sensory processing observed on CPT testing in RLS patients. These results support the notion that the pathophysiology of RLS is multifactorial and not solely driven by dopaminergic dysfunction.

Exploring the Use of the Current Perception Threshold in Pharyngeal Paresthesia Patients.

To explore pharyngeal sensory function by current perception threshold (CPT) measurement in paresthetic pharynx. In total, 58 healthy participants and 66 patients with pharyngeal paresthetic symptoms underwent CPT evaluation. Pharyngeal paresthesia (n = 66) was classified into three categories based on aetiologies: six cases with pain in pharynx; 34 neuropathic patients with glossopharyngeal nerve and/or vagus nerve or recurrent laryngeal nerve injury; and 26 patients with globus pharyngeus. CPT measurements were obtained from bilateral palatoglossal arch and tongue base at 2000, 250 and 5Hz stimulation frequencies. Ranked from high to low, the CPT values for the bilateral palatoglossal arches and tongue bases were: lower cranial neuropathic patients, globus pharyngeus, healthy participants and patients with pain. The CPT values for neuropathic patients on the injured side were significantly higher than those on the healthy side (P < 0.05). The CPT values for patients with pain in pharynx were significantly lower than those of healthy participants (P < 0.05) when the bilateral tongue bases were stimulated. The CPT measurement is a reliable method for quantitatively assessing pharyngeal sensory function and able to differentiate pharyngeal paresthesia between lower cranial neuropathic and subjective discomfort. Pharyngeal sensory function is more sensitive in patients with pain in pharynx. Pharyngeal sensory function is significantly reduced in lower cranialneuropathic patients, especially on the injured side. Patients with globus pharyngeus have pharyngeal hyposensitivity.

Imaging with [99mTc]HMPAO - a novel perspective: investigation of [99mTc]HMPAO leg muscle uptake in metabolic diseases.

Sensitive imaging modalities in the diagnosis of microcircular complications of the lower extremities induced by metabolic diseases are becoming a focus of interest. To investigate the [99mTc]HMPAO uptake of the legs in type 2 diabetes mellitus (T2DM) and obesity, and to search for associations with clinical parameters and nerve conducting studies. A total of 57 patients with controlled T2DM and 46 obese participants without DM were enrolled in the study. [99mTc]HMPAO SPECT/CT examinations were performed to evaluate the radiopharmaceutical accumulation of the legs. For the quantitative assessment of tracer uptake, standardized uptake value (SUVpeak) was measured in fixed spheric volumes of interest placed on both sural muscles on the attenuation-corrected images. Measurement of current perception threshold applying Neurometer (NM-01/CPT) was used to evaluate peripheral nerve dysfunction. Laboratory parameters assessing the glucose homeostasis of the study participants were also measured. In the diabetic group, significantly lower leg SUV values were detected compared to the non-DM obese group (median: 0.517 vs. 0.607; P < 0.001). Body mass index (BMI) (P < 0.0001), age (P = 0.0283), HbA1c (P = 0.0068), and glucose level (P = 0.0044) proved to be significant predictors of muscle tracer uptake. Neurometer studies showed positive correlation with HbA1c levels in the T2DM group (P = 0.0002). We assume that [99mTc]HMPAO uptake of leg muscles is associated with microcirculation, so quantitative [99mTc]HMPAO SPECT/CT might be a sensitive method for evaluating lower limb microvascular alterations. BMI, age, HbA1c, and glucose level may be significant predictors of peripheral vascular abnormalities triggered by metabolic disturbances.

A test-retest reliability study of assessing small cutaneous fibers by measuring current perception threshold with pin electrodes.

BackgroundThe quantitative measurement of current perception threshold (CPT) has been used as a method to assess the function of nerve fibers in neuropathy diseases. The aim of this study was to assess the test-retest reliability measuring CPT using the circular pin electrodes for assessing the function of cutaneous thin nerve fibers.MethodsCPT measurement was repeated on two separate days with at least one-week interval in 55 volunteers. Superficial blood flow (SBF) and skin temperature (ST) were measured on the skin in an around area concentric to the circular pin electrodes after the process of finding CPTs. The coefficient of variation (CV) and intra-class correlation coefficient (ICC) were calculated. The correlation between each two of CPT, SBF increment and ST increment was analyzed.ResultsNo significant differences were found for CPT, SBF and ST between two sessions. SBF was found to be significantly increased after the process of finding CPT. CPT values of males were found to be higher than females. SBF increment was found to be positively correlated with ST increment. The ICC values for CPT, SBF and ST were 0.595, 0.852 and 0.728, respectively. The CV values for CPT, SBF and ST were 25.53%, 12.59% and 1.94%, respectively.ConclusionsThe reliability of CPT measurement using circular pin electrodes is fair, and need consistence of measurements in longitudinal studies.

Measurement reliability of current perception threshold and pain threshold in parallel with blood sampling.

The irritation and pain associated with oral blood sampling necessary to monitor glycemic control can alter oral sensation, but no studies have measured the reliability of oral sensation testing when performed concurrently with blood sampling. The primary and secondary aims of this study were to verify the measurement reliability of current perception threshold (CPT) and pain threshold (PT) tests performed before and after blood sampling and to investigate the differences in CPTs/PTs obtained from the oral cavity, hand, and foot, respectively. CPT/PT measurements were obtained from the oral mucosa and the tips of fingers and toes of 18 volunteers (10 males and 8 females, average age = 26.3 years) using electrical stimulation at frequencies of 5, 250, and 2,000 Hz. Participants also provided blood samples by pricking their own index fingers with a small needle. All subjects completed the following 3 conditions at once‐weekly intervals as follows: (a) sensory measurements followed by blood sampling (SB block); (b) blood sampling followed by sensory measurements (BS block); (c) sensory measurements without blood sampling (CO control block). Cronbach's α coefficients were over 0.78 for the SB, BS, and CO blocks, and are considered to be acceptable for assuring measurement reliability. The oral cavity had significantly lower CPT/PTs than both hands and feet, such that the threshold increased in the order oral cavity < hand < foot. CPT and PT measurements performed concurrently with blood sampling are both reliable and region specific, and for which the oral cavity is the most sensitive testing region.

Is there a connection between postprandial hyperglycemia and IGT related sensory nerve dysfunction?

Background and aimsTo assess the risk factors for sensory nerve dysfunction in subjects with isolated impaired glucose tolerance (IGT). Methods and resultsSeventy-two people with isolated IGT (WHO 1999 criteria) and 39 gender and age-matched healthy volunteers underwent detailed clinical and neurological assessment including quantitative sensory testing using the Neurometer device (current perception threshold measurement on four limbs at three different frequencies). Sensory nerve dysfunction was defined as at least two abnormalities on any frequencies on the upper or lower limbs.Sensory nerve dysfunction was more prevalent among subjects with IGT compared to controls (58.3 vs. 10.3%, OR: 11.23, 95%CI: 3.57–35.35). This association was not influenced by BMI, systolic and diastolic blood pressure, heart rate and autonomic neuropathy (multiple adjusted OR: 13.87, 95%CI: 3.18–60.58), but further adjustment for glycaemic measures abolished the association (OR: 1.58, 95%CI: 0.07–35.68). Assessing the components of glycaemic measures separately, the association between sensory nerve dysfunction and IGT was not affected by HbA1c (OR: 13.94, 95%CI: 1.84–105.5). It was, however, substantially attenuated by fasting plasma glucose (OR: 6.75, 95%CI: 1.33–34.27) while the significance was lost after adjustment for 120 min postload glucose level (OR: 3.76, 95%CI: 0.26–54.10). In the pooled population assessed, independent determinants of sensory nerve dysfunction were older age, 120 min glucose, higher height and cardiovascular autonomic neuropathy at near significance. ConclusionsSensory nerve dysfunction amongst subjects with IGT was not explained by cardiovascular covariates, only by glycaemic measures. In addition to 120 min glucose, cardiovascular autonomic neuropathy at borderline significance, age, and height were the independent determinants of sensory nerve dysfunction.

Quantitative sensory test for primary restless legs syndrome/Willis–Ekbom disease using the current perception threshold test

BackgroundRestless legs syndrome/Willis–Ekbom disease (RLS/WED) is a sensorimotor neurological disorder, and it is especially aggravated at night. The purpose of this study was to investigate the diurnal sensory dysfunction in primary RLS/WED using the current perception threshold (CPT) test, compared to healthy controls. MethodsThirty primary RLS/WED subjects and 30 healthy controls were enrolled. The severity of RLS/WED and sleep problems were evaluated in all subjects. Peripheral polyneuropathy was excluded through neurological examination and nerve conduction study. We used the Neurometer® system for the CPT test and applied three different parameters (2000 Hz, 250 Hz, and 5 Hz), to stimulate both big toes. The CPT test was performed twice, once during the asymptomatic daytime period and again in the evening, when the patients were symptomatic. ResultsThe mean ages of the RLS/WED group and controls were 50.5 ± 11.7 (22; 73.3% female), and 46.3 ± 11.4 (24; 80.0% female), respectively. The mean international RLS/WED study group severity scale score was 28.6 ± 4.25. There was no significant difference in the current perception thresholds between the RLS/WED patients and controls in daytime. However, the RLS/WED patients had lower mean CPT measurements for all three stimulation protocols in the evening (2000 Hz: 393.2 ± 93.7 vs 430.8 ± 79.6, 250 Hz: 172.0 ± 48.4 vs 198.5 ± 38.2, and 5 Hz: 98.0 ± 34.1 vs 124.6 ± 31.3), while the healthy controls showed no difference. ConclusionsRLS patients showed a lower CPT in the evening. The diurnal variation of hyperalgesia in RLS/WED patients indicates a central (circadian) sensory processing disturbance rather than a peripheral disturbance.

Sensory function assessment of the human male lower urinary tract using current perception thresholds

To evaluate the feasibility and reliability of current perception threshold (CPT) measurement for sensory assessment of distinct locations in the male lower urinary tract (LUT). Twelve male subjects (>18 years) without LUT symptoms or medical comorbidities were eligible. CPTs were determined twice (interval: 7-20 days) at the bladder dome, trigone and the proximal, membranous, and distal urethra. Square wave electrical stimulation of 3 Hz/0.2 ms and 0.5 Hz/1 ms was applied using a transurethral 8F catheter placed under fluoroscopic control. Bladder volume was kept constant (60 mL) using a second 10F catheter. Repetitive measurements and reliability were assessed by analysis of variance (ANOVA) and intraclass correlation coefficient (ICC). The ANOVA revealed significant main effects for stimulation site (P = 0.008) and type of stimulation (P < 0.001) with lower CPTs for 0.5 Hz/1 ms compared to 3 Hz/0.2 ms. There was no significant effect for visit number (P = 0.061). CPTs were higher for bladder dome than for proximal (0.5 Hz/1 ms: P = 0.022; 3 Hz/0.2 ms: P = 0.022) and distal urethra (0.5 Hz/1 ms: P = 0.026; 3 Hz/0.2 ms: P = 0.030). Reliability of CPT measurements was excellent to good (ICC = 0.67-0.96) except for the bladder dome (5 Hz/1 ms: ICC = 0.45; 3 Hz/0.2 ms: ICC = 0.20) and distal urethra (3 Hz/0.2 ms: ICC = 0.57). CPTs can be reliably detected at different LUT locations. However, alert and compliant subjects are essential. CPTs of LUT may become a complementary assessment method providing information on responsiveness and sensitivity of afferent LUT nerves. This is especially relevant for urethral afferents, which are not covered by standard urodynamic investigations. Neurourol. Urodynam. 36:469-473, 2017. © 2016 Wiley Periodicals, Inc.

Assessment of Peripheral Neuropathy Using Measurement of the Current Perception Threshold with the Neurometer® in patients with type 1 diabetes mellitus

ObjectiveThe aim of this study is to evaluate the role of current perception threshold (CPT) measurement in peripheral neuropathy in type 1 diabetic patients by using the Neurometer®, a nerve measuring instrument. Methods52 patients with type 1 diabetes mellitus with a disease duration of less than five years and normal neuropathy symptom score (NSS), neuropathy disability score (NDS) and sensory nerve conduction velocity (SCV), and 40 healthy controls were enrolled in this study. Measurement of CPT using the Neurometer® at 2000, 250 and 5Hz assesses function in the bilateral median nerve and sural nerve in all studied cases. We also evaluated the glycated hemoglobin, microalbuminuria, urinary albumin/creatinine ratio and other metabolism indexes of all patients. ResultsThe CPT of the bilateral median nerve and sural nerve was significantly lower in diabetic patients (P<0.01). Moreover, the number of median nerve injuries in the diabetic group (left side 8/52, right side 8/52) is significantly different from the number of its ipsilateral sural nerve injuries (left side 28/52, right side 22/52) (left side P<0.01, right side P<0.01). By comparing those with DPN and those without DPN in the diabetic group, DPN groups had significantly higher glycated hemoglobin (t=2.518, P<0.05). Using binary logistic regression, high glycated hemoglobin was identified to be an independent risk factor of DPN incidence (OR (95% CI): 1.317 (1.013 −1.712), P<0.05). ConclusionThese data suggest that CPT is useful in early detection of peripheral neuropathy in patients with type 1 diabetes mellitus. Patients with diabetic peripheral neuropathy, the lower limb nerve is more vulnerable than the upper limb nerve. In addition, patients with DPN had higher glycated hemoglobin which is an independent risk factor of DPN.

How Can Paresthesia After Zygomaticomaxillary Complex Fracture Be Determined After Long-Term Follow-Up? A New and Quantitative Evaluation Method Using Current Perception Threshold Testing

The aims of the present study were to analyze the effectiveness of current perception threshold (CPT) testing to determine patients' minor paresthesia of the infraorbital region after open reduction and internal fixation (ORIF) for unilateral zygomaticomaxillary bone fracture (UZF) and to clarify which nerve fiber was related to the paresthesia. We conducted a retrospective cohort study of patients who had undergone ORIF after UZF. We also performed neurosensory testing for healthy volunteers who served as the control group. The predictor variables were the period of measurement of Semmes-Weinstein monofilament (S-W) testing and CPT testing (preoperatively and 1 and 5 years postoperatively), measurement side, and disease status (UZF or control). The outcome variables were paresthesia status of the infraorbital nerve region and the results of S-W and CPT testing in both UZF and control groups. The differences in the S-W and CPT values between the affected and unaffected sides in the UZF group and between the UZF and control groups were analyzed by t test (P < .05 was considered significant). The present study included 10 patients (6 males and 4 females), with an average age of 25.0 ± 12.7 years, and 21 controls (10 males and 11 females), with an average age of 24.3 ± 1.7 years. In the control group, the CPT and S-W test results did not show any significant differences between the left and right sides. All 10 patients had paresthesia at 1 and 5 years postoperatively. At 5 years postoperatively, the S-W values in all patients showed normalization. From the results of CPT testing, only the A-β fiber function showed significant improvement at 5 years postoperatively. The CPT test was an effective sensory test for determining minor paresthesia that could not be detected using S-W testing. Paresthesia of the infraorbital nerve region was caused by the damaged A-δ and C fibers.

Measurement of current perception thresholds using the Neurometer(®) - applicability in diabetic neuropathy.

The incidence of diabetes mellitus is continuously growing worldwide, while the specific chronic complications that it induces have a negative impact on life expectancy andquality, entailing extremely high costs of healthcare services. Diabetic peripheral neuropathy is one of the most common chronic complications of diabetes, affecting almost half of diabetic people during life.This review aims at summarizing the evidence on the advantages and the usefulness of current perception threshold measurement for peripheral diabetic neuropathy assessment. Among the different methods used for the screening and diagnosis of diabetic neuropathy, measurement of current perception threshold using the Neurometer® has the ability to assess three sub-types of nerve fiber by producing transcutaneous electrical stimuli at frequencies of 2000, 250 and 5 Hz.Current evidence shows that this method provides a useful, noninvasive evaluation technique of patients with peripheral nervous system disorders, being able to detect neuropathy in the earliest and asymptomatic stages.

Reproducibility of Electrical Sensory Testing in Lower Urinary Tract at Weekly Intervals in Healthy Volunteers and Women With Non-neurogenic Detrusor Overactivity

To evaluate the reproducibility of a standardized technique of current perception threshold measurements with square wave and sine wave current, with monopolar and bipolar electrodes in a cohort of patients with overactive bladder (OAB) and healthy volunteers. We enrolled 6 female nulliparous healthy volunteers and 11 female patients with OAB. Current perception threshold measurements of the bladder were performed using several techniques. The same sequence was used for all 3 measurements performed at weekly intervals to assess the reproducibility. An intraclass correlation coefficient >0.75 was considered as very good reproducibility. All the different stimulation forms were well tolerated by all participants and all experienced stimulation at 2.5-Hz and 95-Hz square wave current. The results with sine wave current showed less uniform results. The intraclass correlation showed the greatest reproducibility with bipolar stimulation at a current of 95 Hz. Sine wave current at 5 Hz and 250 Hz showed low reproducibility. Bipolar stimulation had significantly lower thresholds than monopolar stimulation (P < .0001). No significant differences were found between the healthy subjects and the patients with OAB for the 4 settings. In the healthy volunteers and patients with OAB, the determination of the current perception threshold in the bladder using a standardized method is feasible and well tolerated, with both bipolar and monopolar stimulation. In our study, square wave current showed strong reproducibility at weekly intervals at 2.5 Hz and 95 Hz. However, sinusoid current gave weak reproducibility.

Comparison of Current Perception Threshold Electrical Testing to Clinical Sensory Testing for Lingual Nerve Injuries

We performed a retrospective study of lingual nerve injury assessment comparing the techniques of current perception threshold testing versus clinical sensory testing. We designed and implemented a cross-sectional study and enrolled a patient sample with lingual nerve injuries presenting for treatment to the principal investigator. The predictor variables were clinical sensory testing modalities (ie, temperature, nocioception, vibration, 2-point discrimination, brush stroke, and von Frey monofilament perception). The primary outcome variable was the electrical current perception thresholds of the tongue dorsum (neurometer measurements at 5, 250, and 2,000 Hz). Comparisons were established with the ipsilateral affected and contralateral unaffected lingual nerve distributions. The associations between the clinical sensory testing and current perception threshold measurements were assessed using correlation coefficients, with the level of statistical significance set at P < .05. A total of 40 patients (13 males and 27 females) were included in the present study. The average age of these patients was 34 years (range 13 to 66). Significant correlations were observed between the electrical stimulation thresholds at 2,000 Hz and the 2-point discrimination, reaction to brushing, reaction to vibration, and von Frey fiber thresholds, between the electrical stimulation thresholds at 250 Hz to the nociceptive and thermal thresholds, and between the electrical stimulation thresholds at 5 Hz to thermal stimuli. The significant correlations observed in the present study indicate that current perception threshold can be a complementary or alternative tool in the assessment and evaluation of lingual nerve injuries.

Fractionated administration of carboplatin/paclitaxel reduces neurotoxicity in patients with advanced non-small cell lung cancer

The combination of carboplatin/paclitaxel is commonly used as chemotherapy for advanced non-small cell lung cancer. However, the relatively high incidence of neurotoxicity remains a problem. This study was undertaken to determine whether the fractionated administration regimen can reduce the neurotoxicity. Patients with stage III or IV non-small cell lung cancer were randomized to the nonfractionated (NF) dose group, which received paclitaxel (200 mg/m(2)) and carboplatin (area under the concentration-time curve=6) on day 1, or the fractionated dose (F) group, which received paclitaxel (100 mg/m(2)) and carboplatin (area under the concentration-time curve=3) on days 1 and 8. The cycle was repeated every 3 weeks. Peripheral neuropathy was objectively evaluated by measuring the current perception threshold (CPT) in the median nerve using a neurometer. Fourteen and 13 patients were assigned to the NF and F groups, respectively. The incidence of subjective numbness was significantly lower in the F group (15.4%) than in the NF group (57.1%). The CPT value determined at 2000 Hz showed significant increases in the NF group compared with the pretreatment baseline, but no significant changes were observed in the F group. The response rate was comparable in both groups. The fractionated administration of carboplatin/paclitaxel combination therapy showed a significant reduction in neurotoxicity. Measurement of CPT by a neurometer is a useful tool to evaluate the neurotoxicity of anticancer drugs objectively.

Measuring the Influence of Cervical Epidural Steroids on Current Perception Threshold Measures Using a Neurometer®CPT/C - A Case Report

We investigated cervical epidural steroid injection effects on Current Perception Threshold (CPT) measures in a patient with neuropathic pain using the NeurometerAE CPT/C device (Neurotron, Inc Baltimore MD, USA). CPT measures pre injection revealed a significant hypoesthesia in A�¥ and C fibers with normal A�≤ fiber function. CPT testing 24 hours after a cervical epidural injection at the C7-T1 interspace using methylprednisolone and lignocaine revealed normal measures indicating a reversal of

Electrodiagnostic Functional Sensory Evaluation of Patients With Generalized Vulvodynia

To objectively evaluate vulvodynia by the current perception threshold (CPT) neurometer. Neuroselective CPT measures of the pudendal nerve were obtained at the perineum by a neurometer (Neurotron, Inc, Baltimore, MD), using constant alternating sinusoid waveform electrical stimulus at 2,000-, 250-, and 5-Hz frequencies, in 20 healthy volunteers and 38 women with vulvodynia. The mean +/- SD CPT values in vulvodynia and healthy (control) women were analyzed with the Student t test. Women with vulvodynia showed lower mean CPT values (p <.01). Results of this study support a neuroselective sensory dysfunction in generalized vulvodynia. The field is opened for CPT measures in vulvodynia in selecting therapy strategy, monitoring response to treatment, and assessing vestibulodynia. Assessment of threshold values in a greater number of controls is needed to set a cutoff in CPT values for diagnosis and to grade the severity of the diseases.

Overactive Bladder Is Not Only Overactive but Also Hypersensitive

To evaluate differences in bladder filling sensations and current perception threshold (CPT) values between patients with and without overactive bladder (OAB), and to further investigate the correlation between CPT values and voiding patterns in OAB patients. Detrusor overactivity and bladder volumes at first sensation of bladder filling, first desire to void, and strong desire to void during filling cystometry were compared between 55 female patients with OAB and 42 with non-OAB. CPT measurements from the bladder mucosa taken after neuroselective electrostimulation at frequencies of 2000, 250, and 5 Hz were compared between the 2 groups. In OAB patients, the correlations between CPT values and voiding variables based on 3-day bladder diaries were investigated. OAB patients showed significantly more detrusor overactivity than non-OAB patients (P <.05). Bladder volumes at first sensation of bladder filling, first desire to void, and strong desire to void were significantly lower in OAB patients than in non-OAB patients (P <.05). CPT values at all 3 frequencies were also significantly lower in OAB patients (P <.05). The total number of urgency episodes correlated with CPT values at 250 (r = -0.274, P = .045) and 5 Hz (r = -0.293, P = .032). The total number of urge incontinence episodes also correlated with CPT values at 250 (r = -0.279, P = .041) and 5 Hz (r = -0.272, P = .046). Bladder sensory profiles displayed a more sensitive bladder in OAB patients compared with non-OAB subjects. OAB patients may have bladders that are not only overactive, but also hypersensitive.

Current perception threshold and the HAVS Stockholm sensorineural scale

It is important to determine which tests of sensorineural dysfunction identify the neurological damage from hand-arm vibration exposure. To examine the association between the hand-arm vibration syndrome (HAVS) Stockholm sensorineural scale stages and tests of peripheral neurological function including measurement of current perception threshold (CPT) and nerve conduction. All the subjects were men who were assessed for HAVS with a medical and occupational history and physical examination to determine the Stockholm stage, CPT testing at frequencies of 5, 250 and 2000 Hz for the median and ulnar nerves and measurement of nerve conduction carried out in a blinded fashion. A total of 155 of the 157 recruited subjects agreed to take part in the study, a 99% participation rate. CPT was statistically significantly increased (P < 0.001) in both Stockholm sensorineural Stages 1 and > or =2 in comparison to Stage 0 for every frequency and nerve combination. However, CPT could not discriminate well between Stages 1 and > or =2. There was no association between median or ulnar neuropathy measured by nerve conduction and the Stockholm stages. Polychotomous multinomial logistic regression indicated that the CPT measurements at 2000 Hz, corresponding to damage to large myelinated nerve fibres, were most predictive of both Stockholm Stages 1 and > or =2 in comparison to Stage 0. Neuropathy measured by nerve conduction was unrelated to the Stockholm scale stages. CPT was increased above Stage 0 but did not distinguish well between the higher stages of the Stockholm scale.

Quantitative assessment of sensory functions after 3 surgical approaches for trigeminal neuralgia by current perception threshold measurement

Objective To quantitatively identify and grade trigeminal sensory functions after 3 major surgical procedures of trigeminal neuralgia using a newly developed quantitative sensory testing technique, current perception threshold measurement (CPTM). Methods In the current study, there were 48 trigeminal neuralgia patients without history of prior surgical treatment. These patients received one of the following 3 surgical procedures, microvascular decompression (MVD), peripheral nerve block with alcohol (PNB), or percutaneous radiofrequency thermocoagulation (PRFT). The quantitative sensory testing measurement, CPTM, and conventional qualitative sensory testing measurements were performed preoperatively and postoperatively to evaluate and grade the trigeminal sensory functions. All 3 major cutaneous sensory fiber types, large myelinated fibers (A beta), small myelinated fibers (A delta) and unmyelinated fibers(C) were allowed to quantitatively evaluate and grade by CPTM. The results of the measurements were statistically analyzed using a one-way analysis of variance (single factor). Each subject was his/her own control for comparison of the preoperative to postoperative state on the asymptomatic and symptomatic sides. Subjects were tested 48 h preoperatively and 4 weeks postoperatively. Results PNB with alcohol and PRFT caused significant sensory dysfunction postoperatively in every fiber type, indicating damage to all fibers. On the contrary, the sensory function in all 3 fiber types was unchanged after MVD management. Conclusion Among the 3 major surgical procedures tested, only MVD preserves sensory function in trigeminal system. CPTM is of quantitative nature on the evaluation of sensory functions of nerve fibers

Nerve conduction studies and current perception thresholds in workers assessed for hand-arm vibration syndrome

Workers exposed to hand-arm vibration are at risk of developing the neurological abnormalities of hand-arm vibration syndrome (HAVS). The Stockholm classification of the neurological component of HAVS is based on history and physical examination. There is a need to determine the association between neurological tests and the Stockholm scale. The main objective of this study was to compare the Stockholm neurological scale and the results of current perception threshold (CPT) tests and nerve conduction studies (NCS). Detailed physical examinations were done on 162 subjects referred for HAVS assessment at a specialist occupational health clinic. All subjects had NCS and measurement of CPT. The Stockholm neurological classification was carried out blinded to the results of these neurological tests and compared to the test results. The nerve conduction results indicated that median and ulnar neuropathies proximal to the hand are common in workers being assessed for HAVS. Digital sensory neuropathy was found in only one worker. Neither the nerve conduction results nor the current perception results had a strong association with the Stockholm neurological scale. Exposure to vibration in total hours was the main variable associated with the Stockholm neurological scale [right hand: OR 1.30, 95% CI (1.10-1.54); left hand: OR 1.18, 95% CI (1.0-1.39)]. Workers being assessed for HAVS should have nerve conduction testing to detect neuropathies proximal to the hand. Quantitative sensory tests such as current perception measurement are insufficient for diagnostic purposes but may have a role in screening workers exposed to vibration.