Vibration Detection Threshold Research Articles

Non-obese lipedema patients show a distinctly altered quantitative sensory testing profile with high diagnostic potential.

Lipedema is a widespread severe chronic disease affecting mostly women. Characterized by painful bilateral fat accumulation in extremities sparing hands and feet, objective measurement-based diagnosis is currently missing. We tested for characteristic psychometric and/or sensory alterations including pain and for their potential for medical routine diagnosis. Pain psychometry was assessed using the German Pain Questionnaire. Sensory sensitivity toward painful and nonpainful stimuli was characterized in non-obese lipedema patients and matched controls using the validated quantitative sensory testing (QST) protocol of the German Research Network on Neuropathic Pain. Lipedema patients showed no overt psychometric abnormalities. Pain was reported as somatic rather than psychosomatic aversive. All QST measurements were normal, but the z-score of pressure pain thresholds (PPT) was twofold reduced and the z-score of vibration detection thresholds (VDT) was two and a half times increased. Both thresholds were selectively altered at the affected thigh but not the unaffected hand. Receiver operating characteristic analysis of the combination of PPT and VDT of thigh vs hand into a PVTH score (PPT, VDT, thigh, hand-score) shows high sensitivity and specificity, categorizing correctly 95.8% of the participants as lipedema patients or healthy controls. Bayesian inference analysis corroborated the diagnostic potential of such a combined PVTH score. We propose to assess PPT and VDT at the painful thigh and the pain-free hand. Combination in a PVTH score may allow a convenient lipedema diagnosis early during disease development.

Assessment of somatosensory profiles by quantitative sensory testing in children and adolescents with and without cerebral palsy and chronic pain

ObjectiveWe investigated differences in somatosensory profiles (SSPs) assessed by quantitative sensory testing in children and adolescents with cerebral palsy (CCP) with and without chronic pain and compared these differences to those in a group of typically developed children and adolescents (TDC) with and without chronic pain. MethodAll included subjects were consecutively recruited from and tested at the same outpatient orthopedic clinic by the same investigator. The subjects had their reaction times tested. The SSP consisted of the following tests: warmth (WDT), cool (CDT), mechanical (MDT), and vibration (VDT) detection thresholds; heat (HPT), pressure (PPT), and mechanical (MPT) pain thresholds; wind-up ratio (WUR); dynamic mechanical allodynia (DMA) and cold pressor test (CPT) using a conditioned pain modulation (CPM) paradigm. ResultsWe included 25 CCP and 26 TDC. TDC without chronic pain served as controls. In TDC with chronic pain, WDT, HPT, HPT intensity, and PPT were higher than in controls. No differences in SSPs between CCP with and without chronic pain were observed. In CCP, the MDT, WDT, CDT, and HPT intensity were higher than in controls. CCP had longer reaction times than TDC. There were no differences regarding the remaining variables. DiscussionIn CCP, the SSPs were independent of pain status and findings on MR images. In all CCP the SSPs resembled TDC with chronic pain, compared to TDC without chronic pain. This suggests that CCP do not have the normal neuroplastic adaptive processes that activate and elicit functional changes in the central and peripheral nervous systems.

Reliability of a clinical sensory test battery in patients with spine-related leg and arm pain.

The current standard to evaluate the presence of somatosensory dysfunctions is quantitative sensory testing, but its clinical utility remains limited. Low-cost and time-efficient clinical sensory testing (CST) batteries have thus been developed. Recent studies show moderate to substantial reliability in populations with neuropathic pain. This study evaluates the inter- and intra-tester reliability of people with spine-related leg and arm pain, representing mixed pain mechanisms. Fifty-three patients with spine-related leg (n = 41) and arm pain (n = 12) attended three CST sessions. The CST battery consisted of eleven tests, determining loss and gain of sensory nerve function. CST was performed by the same investigator twice and by an additional investigator to determine inter- and intra-tester reliability. Fleiss' (inter-tester) and Cohen's (intra-tester) kappa were calculated for dichotomized and intraclass correlation coefficients (ICC) for continuous outcomes. Fleiss' kappa varied among modalities from fair to substantial (κ = 0.23-0.66). Cold, warm, and vibration detection thresholds and cold and pressure pain thresholds reached kappa >0.4 (moderate to substantial reliability). Cohen's kappa ranged from moderate to substantial (κ = 0.45-0.66). The reliability of the windup ratio was poor (ICC <0.18). CST modalities with moderate to substantial inter-tester reliability could be of benefit as a screening tool. The moderate to substantial intra-tester reliability for all sensory modalities (except windup ratio) supports their potential use in clinical practice and research to monitor somatosensory changes over time in patients with spine-related limb pain of mixed pain mechanisms. We already know that most modalities of clinical sensory test (CST) batteries achieve moderate to substantial inter- and intra-tester reliability in populations with neuropathic pain. This study evaluates the reliability of a CST battery in populations with mixed pain mechanisms. We found inter-tester reliability varied from poor to substantial for sensory modalities, questioning the value of some CST modalities. The CST battery showed moderate to substantial intra-tester reliability, suggesting its usefulness to monitor sensory changes over time in this cohort.

Longitudinal Change in Serum Neurofilament Light Chain in Type 2 Diabetes and Early Diabetic Polyneuropathy: ADDITION-Denmark.

To investigate the longitudinal development of neurofilament light chain (NfL) levels in type 2 diabetes with and without diabetic polyneuropathy (+/-DPN) and to explore the predictive potential of NfL as a biomarker for DPN. We performed retrospective longitudinal case-control analysis of data from 178 participants of the Anglo-Danish-Dutch Study of Intensive Treatment in People with Screen-Detected Diabetes in Primary Care-Denmark (ADDITION-Denmark) cohort of people with screen-detected type 2 diabetes. Biobank samples acquired at the ADDITION-Denmark 5- and 10-year follow-ups were analyzed for serum NfL (s-NfL) using single-molecule array, and the results were compared with established reference material to obtain NfL z-scores. DPN was diagnosed according to Toronto criteria for confirmed DPN at the 10-year follow-up. s-NfL increased over time in +DPN (N = 39) and -DPN participants (N = 139) at levels above normal age-induced s-NfL increase. Longitudinal s-NfL change was greater in +DPN than in -DPN participants (17.4% [95% CI 4.3; 32.2] or 0.31 SD [95% CI 0.03; 0.60] higher s-NfL or NfL z-score increase in +DPN compared with -DPN). s-NfL at the 5-year follow-up was positively associated with nerve conduction studies at the 10-year follow-up (P = 0.02 to <0.001), but not with DPN risk. Areas under the curve (AUCs) for s-NfL were not inferior to AUCs for the Michigan Neuropathy Screening Instrument questionnaire score or vibration detection thresholds. Higher yearly s-NfL increase was associated with higher DPN risk (odds ratio 1.36 [95% CI 1.08; 1.71] per 1 ng/L/year). Our findings suggest that preceding s-NfL trajectories differ slightly between those with and without DPN and imply a possible biomarker value of s-NfL trajectories in DPN.

Altered foot placement modulation with somatosensory stimulation in people with chronic stroke

Many individuals who experience a stroke exhibit reduced modulation of their mediolateral foot placement, an important gait stabilization strategy. One factor that may contribute to this deficit is altered somatosensory processing, which can be probed by applying vibration to the involved muscles (e.g., the hip abductors). The purpose of this study was to investigate whether appropriately controlled hip abductor vibration can increase foot placement modulation among people with chronic stroke. 40 people with chronic stroke performed a series of treadmill walking trials without vibration and with vibration of either the hip abductors or lateral trunk (a control condition) that scaled with their real-time mediolateral motion. To assess participants’ vibration sensitivity, we also measured vibration detection threshold and lateral sway evoked by abductor vibration during quiet standing. As a group, foot placement modulation increased significantly with either hip or trunk vibration, compared to without vibration. However, these changes were quite variable across participants, and were not predicted by either vibration detection threshold or the lateral sway evoked by hip vibration during standing. Overall, we found that somatosensory stimulation had small, positive effects on post-stroke foot placement modulation. Unexpectedly, these effects were observed with both hip abductor and lateral trunk vibration, perhaps indicating that the trunk can also provide useful somatosensory feedback during walking. Future work is needed to determine whether repeated application of such somatosensory stimulation can produce sustained effects on this important gait stabilization strategy.

Psychophysiological and Neurophysiological Correlates of Dropping Objects from Hands in Carpal Tunnel Syndrome.

Dropping objects from hands (DOH) is a common symptom of carpal tunnel syndrome (CTS). We evaluated the clinical, neurophysiological, and psychophysiological features of 120 CTS patients to elucidate the DOH pathophysiology. Forty-nine healthy controls were included. In the patients, the Boston Carpal Tunnel Questionnaire (BCTQ), the Douleur Neuropathique 4 questions (DN4), and a numeric rating scale for pain (NRS) were evaluated. In patients and controls, we evaluated bilateral median and ulnar motor and sensory nerve conduction studies, cutaneous silent period and cutaneomuscular reflexes (CMR) of the abductor pollicis brevis, cold-detection threshold (CDT) and heat-pain detection threshold (HPT) at the index, little finger, and dorsum of the hand, and vibratory detection threshold at the index and little finger by quantitative sensory testing. CTS with DOH had higher BCTQ, DN4 and NRS, lower median sensory action potential, longer CMR duration, lower CDT and higher HPT at all tested sites than controls and CTS without DOH. Predictive features for DOH were abnormal CDT and HPT at the right index and dorsum (OR: 3.88, p: 0.03) or at the little finger (OR: 3.27, p: 0.04) and a DN4 higher than 4 (OR: 2.16, p < 0.0001). Thermal hypoesthesia in median and extra-median innervated territories and neuropathic pain are predictive of DOH in CTS.

Structural Changes of Cutaneous Immune Cells in Patients With Type 1 Diabetes and Their Relationship With Diabetic Polyneuropathy.

Diabetic polyneuropathy (DPN) is a complication of diabetes characterized by pain or lack of peripheral sensation, but the underlying mechanisms are not yet fully understood. Recent evidence showed increased cutaneous macrophage infiltration in patients with type 2 diabetes and painful DPN, and this study aimed to understand whether the same applies to type 1 diabetes. The study included 104 participants: 26 healthy controls and 78 participants with type 1 diabetes (participants without DPN [n = 24], participants with painless DPN [n = 29], and participants with painful DPN [n = 25]). Two immune cells, dermal IBA1+ macrophages and epidermal Langerhans cells (LCs, CD207+), were visualized and quantified using immunohistological labeling and stereological counting methods on skin biopsies from the participants. The IBA1+ macrophage infiltration, LC number density, LC soma cross-sectional area, and LC processes were measured in this study. Significant difference in IBA1+ macrophage expression was seen between the groups (p = 0.003), with lower expression of IBA1 in participants with DPN. No differences in LC morphologies (LC number density, soma cross-sectional area, and process level) were found between the groups (all p > 0.05). In addition, IBA1+ macrophages, but not LCs, correlated with intraepidermal nerve fiber density, Michigan neuropathy symptom inventory, (questionnaire and total score), severity of neuropathy as assessed by the Toronto clinical neuropathy score, and vibration detection threshold in the whole study cohort. This study showed expressional differences of cutaneous IBA1+ macrophages but not LC in participants with type 1 diabetes-induced DPN compared with those in controls. The study suggests that a reduction in macrophages may play a role in the development and progression of autoimmune-induced diabetic neuropathy.

Quantitative sensory testing in a large cohort of neuropathy patients

Background:&#x0D; Quantitative sensory testing (QST) is a subjective but reliable and quantifiable method to detect patient thresholds to different sensory stimuli. QST is used to measure small- and large-fiber nerve function and can be used in conjunction with other diagnostic modalities in the evaluation of peripheral neuropathy (PN). The utility of QST to distinguish among different types of PN, however, has not been explored. The objective of the study was to evaluate if different patterns of QST abnormalities could distinguish between PN types.&#x0D; Methods:&#x0D; This single-center retrospective cohort study evaluated the frequency of QST abnormalities to vibratory, cold and heat detection thresholds in a large population of PN cases evaluated at the University of Texas Southwestern Medical Center peripheral neuropathy clinic between 1995-2000. PN was categorized by etiology.&#x0D; Results:&#x0D; A total of 559 QST studies were performed in this study. The average age of patients (n=557) was 60 years with a male-to-female ratio of 1:1. The most common diagnosis was cryptogenic sensory polyneuropathy (CSPN, n=294), followed by Charcot–Marie–Tooth disease (n=84)). Meta-regression of vibration and cold indicate that the expected proportion of abnormal responses is less for the vibration test (p = 0.0002), relative to the cold test. However, no differences were observed between diagnoses.&#x0D; Conclusions:&#x0D; Though abnormal QST thresholds were seen in most patients with PN, patterns of QST abnormalities do not distinguish between different types of PN. The routine clinical utility of QST is likely limited.

TOUCH SENSATION IS AN UNDERSTUDIED PREDICTOR OF DEMENTIA RISK IN OLDER ADULTS

Abstract Few studies have focused on touch sensation as risk factor or marker of dementia, although other sensory impairments are associated with cognitive decline. We studied touch sensation as measured by peripheral sensory nerve function; impairment was defined as insensitivity to 10-g monofilament or vibration detection threshold &amp;gt;130μm of the toe, in 2,174 Black and White participants (52% women; 35% black, aged 70-79 years) from Health, Aging, and Body Composition Study who were ambulatory and without dementia at enrollment. Incident dementia over the following 11 years was determined based on medical records, cognitive scores, and medications. Impaired touch sensation was associated with a 1.63-fold higher risk of dementia (95% CI 1.21, 2.19) after adjustment for demographics, health behaviors, and health conditions. Associations persisted even after additional adjustment for hearing, vision, and smell (HR: 1.45; 95%CI 1.09, 2.03). These findings highlight the underappreciated association between poor touch sensation and risk of dementia.

Mechanistic and thermal characterization of acupuncture for chemotherapy-induced peripheral neuropathy as measured by quantitative sensory testing.

Chemotherapy-induced peripheral neuropathy (CIPN) is a common and debilitating side effect of chemotherapy. Acupuncture is a promising non-pharmacological intervention for CIPN. However, the physiological effects of acupuncture treatment remain poorly understood. We examined the effects of acupuncture on CIPN using semi-objective quantitative sensory testing (QST). We conducted a randomized controlled trial of real acupuncture (RA) and sham acupuncture (SA) compared to usual care (UC) in cancer survivors with moderate-to-severe CIPN. Treatment response was assessed with QST measures of tactile and vibration detection thresholds in hands and feet, thermal detection, and pain thresholds at weeks 0, 8, and 12. Constrained linear mixed model (cLMM) regression was used for statistical analysis. 63 patients completed QST testing. At week 8, vibrational detection thresholds in feet were significantly lower in RA and SA (p = 0.019 and p = 0.046) than in UC, with no difference between RA and SA (p = 0.637). Both RA and SA also showed significantly higher cool thermal detection than UC (p = 0.008 and p = 0.013, respectively), with no difference between RA and SA (p = 0.790). No differences in tactile detection, vibrational detection in hands, warm thermal detection, and thermal pain thresholds were detected among the three arms at weeks 8 and 12. QST demonstrated different patterns in RA, SA, and UC. After eight weeks of RA, we observed significant improvements in the vibrational detection threshold in feet and cool thermal detection threshold in hands compared to UC. No significant differences were seen when compared to SA. ClinicalTrials.gov (NCT03183037); June 9, 2017.

Somatosensory abnormalities after infection with SARS-CoV-2 - A prospective case-control study in children and adolescents.

BackgroundLong-term neurological complaints after SARS-CoV-2 infection occur in 4–66% of children and adolescents. Controlled studies on the integrity of the peripheral nerve system are scarce. Therefore, we examined the somatosensory function in children and adolescents after SARS-CoV-2 infection in a case-control study compared with age-matched individuals.Materials and MethodsEighty-one subjects after SARS-CoV-2 infection (n = 44 female, 11.4 ± 3.5 years, n = 75 SARS-CoV-2 seropositive, n = 6 PCR positive during infection and SARS-CoV-2 seronegative at the time point of study inclusion, n = 47 asymptomatic infection) were compared to 38 controls without SARS-CoV-2 infection (26 female, 10.3 ± 3.4 years, n = 15 with other infection within last 6 months). After standardised interviews and neurological examinations, large fibre (tactile and vibration detection thresholds) and small fibre (cold and warm detection thresholds, paradoxical heat sensation) functions were assessed on both feet following a validated protocol. After z-transformation of all values, all participants were compared to published reference values regarding the number of abnormal results. Additionally, the mean for all sensory parameters values of both study groups were compared to an ideal healthy population (with z-value 0 ± 1), as well as with each other, as previously described. Statistical analyses: t-test, Chi-squared test, and binominal test.FindingsNone of the controls, but 27 of the 81 patients (33%, p < 0.001) reported persistent complaints 2.7 ± 1.9 (0.8–8.5) months after SARS-CoV-2 infection, most often reduced exercise capacity (16%), fatigue (13%), pain (9%), or paraesthesia (6%). Reflex deficits or paresis were missing, but somatosensory profiles showed significantly increased detection thresholds for thermal (especially warm) and vibration stimuli compared to controls. Approximately 36% of the patients after SARS-CoV-2, but none of the controls revealed an abnormal sensory loss in at least one parameter (p < 0.01). Sensory loss was characterised in 26% by large and 12% by small fibre dysfunction, the latter appearing more frequently in children with prior symptomatic SARS-CoV-2 infection. Myalgia/paraesthesia was indicative of somatosensory dysfunction. In all eight re-examined children, the nerve function recovered after 2–4 months.InterpretationThis study provides evidence that in a subgroup of children and adolescents previously infected with SARS-CoV-2, regardless of their complaints, the function of large or small nerve fibres is presumably reversibly impaired.

The Rydel Seiffer tuning fork – Age and gender matter

BackgroundThe Rydel Seiffer tuning fork (RSTF) can be easily applied to evaluate deficits of vibration perception. Standard normative data as stated in textbooks (6/8-thresholds among the “elderly”) is not suitable for an informed decision-making process. ObjectiveTo reevaluate the range of vibration detection thresholds (VDT) based on assessments in healthy Caucasians stratified for age and gender using the RSTF and on a short-review of literature on normative data on PubMed. MethodsMonocentric, prospective assessment of VDT at the dorsal 1st metatarsophalangeal joint of both sides in 77 healthy volunteers. Participants were grouped according to age: 20–39 years (group I, n = 24), 40–59 years (group II, n = 29), 60–79 years (group III, n = 24). Data was stratified for gender. Means were compared via Mann-Whitney U-test; correlations were rated via Pearson correlation coefficient. A short-review of literature was performed on PubMed. ResultsAging related to declined vibration perception (r = −0.446, p < 0.001). Women aged 60 years and older showed better vibration perception compared to men (men: 6.5 ± 1.3, women: 7.5 ± 0.9, p = 0.003). All VDT-limits were higher compared to results gathered in literature (I: 7.9 ± 0.3, II: 7.7 ± 0.5, III: 7.1 ± 1.1). Formerly reported VDT-limits at the lower limbs were scattered (e.g., >4.5/8 to ≥6.6/8 at age 18–29). Current data, especially VDT of participants aged 50 years and older, were largely in line with data reported by Hilz et al. 1998: 18–29 years: ≥ 6.6/8, 30–39 years: ≥ 5.5/8, 40–49 years: ≥ 5.7/8, 50–59 years: ≥ 5.4/8, 60–69 years ≥ 5.2/8, > 70 years ≥ 5.3/8, alternative: 30–39 years ≥ 6.2/8 Magerl et al. 2010. Data on diagnostic sensitivity by Xirou et al. 2020 supported a VDT-limit of 5.9/8 across all ages to aim for high sensitivity. A better vibration perception among elder women compared to men has been described by many studies. DiscussionThe current data and literature underline, that higher VDT-limits stratified for age and gender should be considered in a clinical setting. Until further validation within larger samples, we propose to consider the limits as reported by Hilz et al. 1998. Furthermore, women at age 60 + years presenting with borderline thresholds should be considered for further diagnostic workup.

Linking Signal Relevancy and Intensity in Predictive Tactile Suppression.

Predictable somatosensory feedback leads to a reduction in tactile sensitivity. This phenomenon, called tactile suppression, relies on a mechanism that uses an efference copy of motor commands to help select relevant aspects of incoming sensory signals. We investigated whether tactile suppression is modulated by (a) the task-relevancy of the predicted consequences of movement and (b) the intensity of related somatosensory feedback signals. Participants reached to a target region in the air in front of a screen; visual or tactile feedback indicated the reach was successful. Furthermore, tactile feedback intensity (strong vs. weak) varied across two groups of participants. We measured tactile suppression by comparing detection thresholds for a probing vibration applied to the finger either early or late during reach and at rest. As expected, we found an overall decrease in late-reach suppression, as no touch was involved at the end of the reach. We observed an increase in the degree of tactile suppression when strong tactile feedback was given at the end of the reach, compared to when weak tactile feedback or visual feedback was given. Our results suggest that the extent of tactile suppression can be adapted to different demands of somatosensory processing. Downregulation of this mechanism is invoked only when the consequences of missing a weak movement sequence are severe for the task. The decisive factor for the presence of tactile suppression seems not to be the predicted action effect as such, but the need to detect and process anticipated feedback signals occurring during movement.

Pain mechanisms in carpal tunnel syndrome: a systematic review and meta-analysis of quantitative sensory testing outcomes.

Carpal tunnel syndrome (CTS) is the most common nerve compression in the arm. A mix of peripheral and central contributions on quantitative sensory testing (QST) has been reported in the literature. Thus, this systematic review or meta-analysis aimed to identify the dominant sensory phenotype and draw conclusive evidence about the presence of central sensitization (CS) in CTS. Based on an a priori published protocol and using PRISMA guidelines, 7 databases were searched (Embase, Web of Science, Scopus, PubMed, SAGE, EBSCOhost, and ProQuest). Eligible studies compared the QST findings of individuals with subacute and chronic CTS with those of healthy controls through thermal, mechanical, and vibration detection thresholds; thermal, pressure, and mechanical pain thresholds; mechanical pain sensitivity; presence of allodynia; wind-up ratio; and conditioned pain modulation. Thirty-seven studies were included in the qualitative analysis. Results showed a significant loss of all detection thresholds of hand median nerve territories and hand extramedian areas (little finger and hand dorsum) in CTS ( P < 0.05) but no significant difference ( P > 0.05) in wind-up ratio, cold, heat, or mechanical pain thresholds of the median nerve territories. Furthermore, there was a significant increase in mechanical pain sensitivity in median nerve territories and remotely in the forearm ( P < 0.05) and a significant gain in pressure and heat pain thresholds in the carpal area ( P < 0.05). Conditioned pain modulation was impaired in CTS. Hypoesthesia and increased thermal and mechanical pain ratings are the dominant sensory phenotype with inconclusive evidence about CS in CTS due to the heterogenous results of thermal and mechanical pain thresholds.

Does inflammation explain the link between multiple sensory impairment and dementia?

AbstractBackgroundMultiple sensory impairments are associated with increased risk of dementia, but the underlying mechanisms are unclear. One potential explanation is that the association is due to shared risk factors such as inflammation. Our objective was to evaluate whether multisensory impairment was associated with markers of inflammation (interleukin‐6, and C‐Reactive Protein (CRP) independent of other health conditions and test whether inflammation might explain the association between multisensory impairments and dementia risk.MethodWe studied 1,794 black and white older adults from the Health, Aging, and Body Composition Study, a prospective cohort study of older adults who were aged 70‐79 and dementia‐free at enrollment. Sensory abilities were assessed at study years 3‐5, vision was measured by log contrast sensitivity, hearing by pure tone average at 500, 1,000, 2,000, and 4,000 Hz; smell by the 12‐item Cross Cultural Smell Identification Test; and touch by vibration detection threshold of the big toe. A multisensory score (0‐12) was calculated based on sample quartiles and summed across each sensory domain. Interleukin‐6, and CRP were assayed based on blood sample near baseline and log transformed. Incident dementia over follow‐up was determined based on a combination of hospitalization records, dementia medications, or clinically significant cognitive decline. Using regression models, we investigated the associations between inflammation biomarkers, multisensory impairment, and dementia with adjustment for demographics, health conditions, and health behaviors.ResultBoth measures of inflammation were associated with higher multisensory impairment scores. 1‐log interleukin‐6 was associated with 0.25 points worse multisensory score (95%CI: 0.10, 0.40; p&gt;0.001), 1‐log CRP levels was associated with 0.11 points worse multisensory score (95%CI: 0.01, 0.20; p=0.02). Higher level of interleukin‐6 (HR = 1.18; 95% CI: 1.02, 1.37; p=0.03) but not CRP (p=0.84) was associated increased dementia risk. In adjusted models, a 1‐point increase in the multisensory score was associated with a 14% higher risk of dementia (95% CI: 1.08; 1.20), estimates were similar even after including interleukin‐6 as an explanatory variable.ConclusionInflammation was independently associated with worse multisensory impairment scores. Although inflammation is also associated with dementia, it did not explain the association between multisensory impairment and dementia.

Potential differences in somatosensory function during premenopause and early and late postmenopause in patients with burning mouth syndrome: An observational case–control study

Background/purposeBurning mouth syndrome (BMS) is a chronic condition presenting as intraoral burning or dysesthesia, with a high preponderance in menopausal women. This study aimed to examine the association between somatosensory dysfunction and BMS in premenopausal, early postmenopausal, and late postmenopausal patients, using a standardized Quantitative Sensory Testing (QST) protocol, and to determine the predictive value of thermal or mechanical perception by QST for detecting BMS. Materials and methodsAn observational case–control study was performed with 36 female participants with BMS (12 premenopausal, 10 early postmenopausal, and 14 late postmenopausal) and 42 age- and sex-matched healthy volunteers (21 premenopausal, 10 early postmenopausal, and 11 late postmenopausal). Neurophysiological tests were used to evaluate somatosensory dysfunction at the tongue. ResultsZ-score in the late postmenopausal BMS group revealed a gain of function for the cold pain threshold and heat pain threshold (Z = 2.08 and 3.38, respectively). In the multiple regression analysis with the Visual Analog Scale as the dependent variable, the vibration detection threshold predicted the severity of burning mouth sensation in the premenopausal group. ConclusionLate postmenopausal patients with BMS showed an increased response of the tongue to noxious thermal stimuli. This supports the theory that changes in sex hormones may affect trigeminal somatosensory function, particularly during the late postmenopausal stage in patients with BMS.

Effects of Novel Vibro-Acupuncture on Healthy Subjects and Those with Experimental and Clinical Pain as Assessed by Quantitative Sensory Testing.

To investigate the analgesic effects of vibro-acupuncture (VA), a novel acuvibrator was developed. Objectives: To compare the analgesic effects of VA with those of manual acupuncture (MA) and placebo acupuncture (PA) on subjects with normal sensory perception (Study I), experimentally induced acute pain (Study II), and clinical chronic pain (Study III). Thirty healthy volunteers (21 males, age: 20-30 years) participated in Study I. Fourteen healthy volunteers (8 males, age: 20-32 years) participated in Study II in which experimental pain was induced by injection of hypertonic saline. Fourteen patients suffering from unilateral epicondylalgia (9 males, age: 30-61 years) participated in Study III. All participants received VA, MA, and PA at LI4 and LI10 points in a randomized, crossover, and double-blinded manner. Quantitative sensory testing (QST) was performed on the ipsilateral forearm before and after each treatment. Data were analyzed using repeated-measures (RM) ANOVA. A significantly higher vibration detection threshold (VDT) was observed after treatment of VA than after MA and PA (p < 0.001). No significant treatment effect on experimental pain intensity was detected (p > 0.086). Significantly lower pain intensity (p = 0.005) and a smaller drawing area (p = 0.011) of unilateral epicondylalgia were found after VA treatment than after PA. A specific effect on the VDT beyond that of MA and PA was evoked by VA. Patients with epicondylitis showed significantly lower pain intensity during VA than during PA. This study indicated that VA may be beneficial in individuals with clinical chronic musculoskeletal pain; however, further studies are needed.

Age Differences in Multimodal Quantitative Sensory Testing and Associations With Brain Volume.

Background and ObjectivesSomatosensory function is critical for successful aging. Prior studies have shown declines in somatosensory function with age; however, this may be affected by testing site, modality, and biobehavioral factors. While somatosensory function declines are associated with peripheral nervous system degradation, little is known regarding correlates with the central nervous system and brain structure in particular. The objectives of this study were to examine age-related declines in somatosensory function using innocuous and noxious stimuli, across 2 anatomical testing sites, with considerations for affect and cognitive function, and associations between somatosensory function and brain structure in older adults.Research Design and MethodsA cross-sectional analysis included 84 “younger” (n = 22, age range: 19–24 years) and “older” (n = 62, age range: 60–94 years) healthy adults who participated in the Neuromodulatory Examination of Pain and Mobility Across the Lifespan study. Participants were assessed on measures of somatosensory function (quantitative sensory testing), at 2 sites (metatarsal and thenar) using standardized procedures, and completed cognitive and psychological function measures and structural magnetic resonance imaging.ResultsSignificant age × test site interaction effects were observed for warmth detection (p = .018, 0.10) and heat pain thresholds (p = .014, 0.12). Main age effects were observed for mechanical, vibratory, cold, and warmth detection thresholds (ps < .05), with older adults displaying a loss of sensory function. Significant associations between somatosensory function and brain gray matter structure emerged in the right occipital region, the right temporal region, and the left pericallosum.Discussion and ImplicationsOur findings indicate healthy older adults display alterations in sensory responses to innocuous and noxious stimuli compared to younger adults and, furthermore, these alterations are uniquely affected by anatomical site. These findings suggest a nonuniform decline in somatosensation in older adults, which may represent peripheral and central nervous system alterations part of aging processes.

Simple Quantitative Sensory Testing Reveals Paradoxical Co-existence of Hypoesthesia and Hyperalgesia in Diabetes.

Background: Diabetic neuropathy is characterized by the paradoxical co-existence of hypo- and hyperalgesia to sensory stimuli. The literature shows consistently sensory differences between healthy and participants with diabetes. We hypothesized that due to differences in pathophysiology, advanced quantitative sensory testing (QST) might reveal sensory discrepancies between type 1 (T1D) and type 2 diabetes (T2D). Furthermore, we investigated whether vibration detection thresholds (VDT) were associated with sensory response.Method: Fifty-six adults with T1D [43 years (28–58)], 99 adults with T2D [65 years (57–71)], and 122 healthy individuals [51 years (34–64)] were included. VDT, pressure pain detection thresholds (pPDT) and tolerance (pPTT), tonic cold pain (hand-immersion in iced water), and central pain mechanisms (temporal summation and conditioned pain modulation) were tested and compared between T1D and T2D. VDT was categorized into normal (< 18 V), intermediary (18–25 V), or high (> 25 V).Results: In comparison to healthy, analysis adjusted for age, BMI, and gender revealed hypoalgesia to tibial (pPDT): p = 0.01, hyperalgesia to tonic cold pain: p < 0.01, and diminished temporal summation (arm: p < 0.01; abdomen: p < 0.01). In comparison to participants with T2D, participants with T1D were hypoalgesic to tibial pPDT: p < 0.01 and pPTT: p < 0.01, and lower VDT: p = 0.02. VDT was not associated with QST responses.Conclusion: Participants with T1D were more hypoalgesic to bone pPDT and pPTT independent of lower VDT, indicating neuronal health toward normalization. Improved understanding of differentiated sensory profiles in T1D and T2D may identify improved clinical endpoints in future trials.

Quantitative sensory testing and norepinephrine levels in REM sleep behaviour disorder – a clue to early peripheral autonomic and sensory dysfunction?

IntroductionStudies have reported autonomic impairment in patients with idiopathic REM sleep behaviour disorder (iRBD), which is considered a prodromal stage of alpha-synucleinopathies. It is still debated whether central or peripheral pathologies are first manifestations of alpha-synucleinopathies. This study aimed to characterize autonomic and somatosensory function in iRBD patients.MethodsThis cross-sectional prospective case–control study included 17 iRBD patients (mean age 66.3 ± 9.2 years) and 16 healthy controls (HCs, 66.6 ± 11.3 years). Quantitative sensory testing, neurological and neuropsychological assessments, norepinephrine blood plasma levels, tilt table examination with orthostatic blood pressure, and heart rate variability were carried out. Longitudinal data of 10 iRBD patients, including neurological, neuropsychological, and tilt table examination, were assessed.ResultsiRBD patients more frequently presented with orthostatic dysfunction than HCs (70.6% vs. 6.3%, p < 0.0001). Supine norepinephrine plasma levels were normal, but lower in iRBD (249.59 ± 99.78 pg/ml iRBD, 354.13 ± 116.38 pg/ml HCs, p < 0.05). Quantitative sensory testing revealed impaired cold (CDT) and vibration detection thresholds (VDT) on the foot in iRBD (CDT foot iRBD − 1.24 ± 0.31, HCs − 9.89E-17 ± 0.25, VDT iRBD − 1.11 ± 0.47, HCs − 1.46E-16 ± 0.25, p < 0.05). Cold detection thresholds differed between the foot and hand among iRBD patients (foot − 1.24 ± 0.31, hand − 0.56 ± 0.25, p < 0.05). Longitudinal data revealed an increase in maximum systolic and diastolic orthostatic blood pressure changes and a decrease in the Valsalva ratio in the follow-up group (p < 0.05).ConclusionThis study revealed autonomic dysfunction with somatosensory impairment, and decreased norepinephrine levels in iRBD, which may serve as a possible prodromal marker for developing alpha-synucleinopathy.