Reference Values and Influencing Factors Analysis for Current Perception Threshold Testing Based on Study of 166 Healthy Chinese

Assessment of Peripheral Neuropathy Using Current Perception Threshold Measurement in Patients with Spinocerebellar Ataxia Type 3

Peripheral neuropathy (PN) identified as a significant contributor to disability in Spinocerebellar ataxia type 3 (SCA3) patients. This study seeks to assess the utility of current perception threshold (CPT) measurements in evaluating PN in individuals with SCA3 and aims to identify factors influencing CPT values in SCA3 and ascertain whether these values correlate with the severity of ataxia. Ninety-four patients diagnosed with SCA3 and 44 healthy controls were recruited for this investigation. All participants were performed standard CPT assessments. Comparative analysis was conducted on CPT variables between the groups. Multivariable linear regression models were employed to identify potential risk factors influencing CPT values, and to investigate the association between CPT values and the severity of ataxia in SCA3. The case group exhibited significantly higher values across all CPT variables compared to the control group (P < 0.01). Peripheral neuropathy was prevalent among SCA3 patients, with lower limb nerves demonstrating greater susceptibility than upper limb nerves. Increasing age (β = 1.813, P = 0.012) and heightened ataxia severity (β = 3.763, P = 0.013) as predictors of poorer CPT values. Gender also emerged as a predictor of CPT values. Furthermore, CPT values (β = 0.003, P = 0.013) and disease duration (β = 0.118, P < 0.001) were associated with more severe ataxia. Our findings suggest that the CPT test holds promise for assessing peripheral neuropathy in SCA3 patients and that CPT values may serve as indicators of disease severity in this population.

Quantitative and Fiber-Selective Evaluation for Central Poststroke Pain

The electrophysiological recording can be used to quantify the clinical features of central poststroke pain (CPSP) caused by different lesion locations. We aimed to explore the relationship between clinical features and lesion location in patients with CPSP using the current perception threshold (CPT) approach. Here, patients underwent the standardized CPT measure at five detection sites on both the contralesional and ipsilesional sides, using a constant alternating-current sinusoid waveform stimulus at three frequencies: 2000 Hz, 250 Hz, and 5 Hz. 57 CPSP patients were recruited in this cross-sectional study, including 13 patients with thalamic lesions and 44 patients with internal capsule lesions. Patients with a thalamic lesion had more frequent abnormal Aδ and C fibers than those with an internal capsule lesion (69.2% versus 36.4%, p value = 0.038; 53.8% versus 63.6%, p value = 0.038). The patients with internal capsule lesions had more frequent abnormal Aβ fibers than those with thalamic lesions (53.8% versus 63.6%, p value < 0.001). The sensory dysfunction in the patients with thalamic lesions was more likely to occur in the upper limbs (i.e., the shoulder (p value = 0.027) and the finger (p value = 0.040)). The lower limbs (i.e., the knee (p value = 0.040) and the toe (p value = 0.005)) were more likely to experience sensory dysfunction in the patients with internal capsule lesions. Hyperesthesia was more likely to occur in the thalamic patients, and hypoesthesia was more likely to occur in the patients with internal capsule lesions (p value < 0.001). In patients with thalamic lesions, Visual Analogue Scale (VAS) had a positive correlation with 5 Hz CPT on the shoulder (r = 0.010, p value = 0.005), 250 Hz CPT on the finger (r = 0.690, p value = 0.009) from the contralesional side, and 2000 Hz CPT on the knee (r = 0.690, p value = 0.009). In patients with internal capsule lesions, VAS had a positive correlation with 2000 Hz CPT on the knee (r = 0.312, p value = 0.039) and foot (r = 0.538, p value < 0.001). In conclusion, the abnormal fiber types, sensory dysfunction territory, and clinical signs of CPSP in thalamic stroke differ from those in internal capsule stroke. Implementation of the portable and convenient CPT protocol may help clarify the locations of different stroke lesions in various clinical settings.

Early Detection of Diabetic Peripheral Neuropathy: A Focus on Small Nerve Fibres

Diabetic peripheral neuropathy (DPN) is the most common complication of both type 1 and 2 diabetes. As a result, neuropathic pain, diabetic foot ulcers and lower-limb amputations impact drastically on quality of life, contributing to the individual, societal, financial and healthcare burden of diabetes. DPN is diagnosed at a late, often pre-ulcerative stage due to a lack of early systematic screening and the endorsement of monofilament testing which identifies advanced neuropathy only. Compared to the success of the diabetic eye and kidney screening programmes there is clearly an unmet need for an objective reliable biomarker for the detection of early DPN. This article critically appraises research and clinical methods for the diagnosis or screening of early DPN. In brief, functional measures are subjective and are difficult to implement due to technical complexity. Moreover, skin biopsy is invasive, expensive and lacks diagnostic laboratory capacity. Indeed, point-of-care nerve conduction tests are convenient and easy to implement however questions are raised regarding their suitability for use in screening due to the lack of small nerve fibre evaluation. Corneal confocal microscopy (CCM) is a rapid, non-invasive, and reproducible technique to quantify small nerve fibre damage and repair which can be conducted alongside retinopathy screening. CCM identifies early sub-clinical DPN, predicts the development and allows staging of DPN severity. Automated quantification of CCM with AI has enabled enhanced unbiased quantification of small nerve fibres and potentially early diagnosis of DPN. Improved screening tools will prevent and reduce the burden of foot ulceration and amputations with the primary aim of reducing the prevalence of this common microvascular complication.

Effect of Different Kinesio Taping Interventions on the Local Thresholds of Current Perception and Pressure Pain in Healthy Adults

Objective

Previous studies made controversial claims about the alleged effects of Kinesio taping (KT) on pain relief. To date, the mechanism by which KT relieves pain remains unclear. Moreover, pain evaluation lacks objective and quantitative parameters. This study compared the acute effects of different KT interventions on the local thresholds of pressure pain and current perception in healthy adults to determine the potential mechanisms by which KT relieves pain.

Methods

Thirty healthy female subjects randomly received four KT interventions, namely, no taping (NT), placebo taping (PT), Y strips of KT (KY), and fan strips of KT (KF), on the waist. Current perception threshold (CPT), pressure pain threshold (PPT), soft tissue hardness, and the visual analog scale (VAS) scores of the subjects’ perceived pain were immediately measured after taping. Repeated-measures ANOVA was performed to determine significant differences in these parameters among the four interventions.

Results

Significant differences in CPT values among the interventions were observed at the frequency of 5 Hz (F = 3.499, p = 0.019, η_p² = 0.111). Post hoc analysis revealed that CPT was significantly higher for KF than for NT (p = 0.008, 95% CI = 1.390–11.990). Significant differences in PPT values (F = 4.352, p = 0.012, η_p² = 0.130) and soft tissue hardness (F = 2.957, p = 0.049, η_p² = 0.093) were observed among the different taping conditions. Post hoc analysis revealed that PPT was significantly higher for KF than for PT (p = 0.011, 95% CI = 0.071–0.749), and soft tissue hardness was significantly higher for KF than for NT (p = 0.010, 95% CI = 0.461–4.586) and KY (p = 0.040, 95% CI = 0.059–3.800). No significant differences in self-perceived pain among the interventions were observed.

Conclusion

The healthy adult females had higher PPT values, lower soft tissue hardness, and higher CPT values at 5 Hz under KF intervention applied on the waist than those under the other taping interventions. Moreover, the different taping conditions had no significant differences in terms of VAS of perceived pain. These results provide guidance for the application of KT on pain management.

References Values for the Current Perception Threshold in the Pharynx Based on a Study of a Healthy Population

OBJECTIVES

The application of the current perception threshold (CPT) in the diagnosis of pharyngeal sensory abnormalities has rarely been studied, and there is a lack of reference values for this application. This study established a normal reference range for CPT in the pharynx based on a study of a healthy population.

METHODS

The CPT values of the palatoglossal arch, posterior 1/3 of the lingual body and hard palate were measured in 60 healthy individuals at 2000, 250, and 5 Hz. The influencing factors were analyzed, and reference values for the CPT were established.

RESULTS

There was no correlation between the CPT value and gender. Age was only correlated at 250 Hz level in the hard palate. The CPT values of the palatoglossal arch were 324.95 ± 82.422 at 2000 Hz, 66.90 ± 38.622 at 250 Hz, and 13 ± 14.93 (7.83-22.75) at 5 Hz. The CPT values of the posterior 1/3 of the lingual body were 359.17 ± 76.299 at 2000 Hz, 86.92 ± 35.151 at 250 Hz, and 19 ± 15.73 (13.03-28.75) at 5 Hz. The CPT values of the hard palate were 157.5 ± 61.75 (124-185.75) at 2000 Hz, 57.63 ± 28.785 at 250 Hz, and 22 ± 25.73 (11.03-36.75) at 5 Hz.

CONCLUSIONS

The CPT values of the pharynx in healthy people were not related to gender. The CPT values of the hard palate for 250 Hz stimulation were related to age, and there were no relationships between the CPT values and age for the other frequencies and loci. We established a normal reference range of CPT values in the pharynx from measurements obtained from healthy populations.

Quantitative Evaluation of the Function of the Sensory Nerve Fibers of the Palate in Patients With Obstructive Sleep Apnea

STUDY OBJECTIVES

To quantitatively evaluate the functional integrity of sensory nerve fibers of the palate in patients with obstructive sleep apnea (OSA) using the Neurometer system.

METHODS

A total of 32 patients with OSA and 18 healthy control patients were included in the study. All participants were selected based on medical history, physical examination, and nocturnal polysomnography (PSG) and divided into two groups. The palatal sensory status of participants was examined with a Neurometer current perception threshold (CPT) system. The system was used to deliver an electrical stimulus at three different frequencies (2,000 Hz, 250 Hz, and 5 Hz) by an investigator blinded to the PSG results.

RESULTS

There were no significant differences in the CPT values of the hard palate between the patients with OSA and control patients at any of the three stimulation frequencies. The differences in the CPT values of the soft palate between these groups failed to show any statistical significance at 250 Hz and 5 Hz. However, the patients with OSA showed significantly higher CPT values of the soft palate at 2,000 Hz than the age-matched healthy control patients (256.56 ± 129.34 versus 372.13 ± 152.06; P = .009).

CONCLUSIONS

Our study revealed an impairment of 2,000 Hz-related sensory nerve function of the soft palate among patients with OSA. The CPT test could be a useful tool for the quantitative and selective assessment of the sensory nerve function in patients with OSA. Additional research is required to evaluate the different types of sensory nerve dysfunctions among such patients.

CLINICAL TRIAL REGISTRATION

Registry: ClinicalTrials.gov; Title: The Effects of Nasal Airflow on Upper Airway Dilator Muscles During Sleep; Identifier: NCT03506178; URL: https://clinicaltrials.gov/ct2/show/NCT03506178.

CITATION

An Y, Li Y, Chang W, Gao F, Ding X, Xu W, Han D. Quantitative evaluation of the function of the sensory nerve fibers of the palate in patients with obstructive sleep apnea. J Clin Sleep Med. 2019;15(9):1347-1353.