Testing for sensory threshold in drinking water with added calcium: a first step towards developing a calcium fortified water

Background: Food fortification is an effective strategy that has been recommended for improving population calcium inadequate intakes. Increasing calcium concentration of water has been proposed as a possible strategy to improve calcium intake. The objective of this study was to determine the sensory threshold of different calcium salts added to drinking water using survival analysis. Methods: We performed the triangle test methodology for samples of water with added calcium using three different calcium salts: calcium chloride, calcium gluconate and calcium lactate. For each salt, a panel of 54 consumers tested seven batches of three water samples. Data were adjusted for chance and sensory threshold was estimated using the survival methodology and a discrimination of 50%. Results: The threshold value estimation for calcium gluconate was 587 ± 131 mg/L of water, corresponding to 25% discrimination, for calcium lactate was 676 ± 186 mg/L, corresponding to 50% discrimination, and for calcium chloride was 291 ± 73 mg/L, corresponding to 50% discrimination. Conclusions: These results show that water with calcium added in different salts and up to a concentration of 500 mg of calcium/L of water is feasible. The calcium salt allowing the highest calcium concentration with the lowest perceived changes in taste was calcium gluconate. Future studies need to explore stability and acceptability over longer periods of time.

Application of vibration to the soles reduces minimum toe clearance variability during walking

Minimum toe clearance (MTC) is an important indicator of the risk of tripping. Aging and neuromuscular diseases often decrease MTC height and increase its variability, leading to a higher risk of tripping. Previous studies have developed visual feedback-based gait training systems to modify MTC. However, these systems are bulky and expensive, and the effects of the training continue only for a short time. We paid attention to the efficacy of vibration in decreasing the variability of gait parameters, and hypothesized that proper vibration applied to soles can reduce the MTC variability. Using shoes embedded with active vibrating insoles, we assessed the efficacy of both sub- and supra-threshold vibration in affecting MTC distribution. Experiment results with 17 young and healthy adults showed that vibration applied throughout the walking task with constant intensity of 130% of sensory threshold significantly decreased MTC variability, whereas sub-threshold vibration yielded no significant effect. These results demonstrate that a properly designed tactile sensory input which is controlled and delivered by a simple wearable device, the active insole, can reduce the MTC variability during walking.

Influence of Vibrotactile Random Noise on the Smoothness of the Grasp Movement in Patients in Chemotherapy-Induced Peripheral Neuropathy

Background Patients with chemotherapy-induced peripheral neuropathy (CIPN) often suffer from sensorimotor dysfunction of the distal portion of the extremities (e.g., loss of somatosensory sensation, numbness/tingling, difficulty typing on a keyboard, or difficulty undoing or doing up a button). The present study aimed to reveal the effects of subthreshold vibrotactile random noise stimulation on sensorimotor dysfunction in CIPN patients without exacerbating symptoms. Methods Twenty-five patients with CIPN and 28 age-matched healthy adults participated in this study. To reveal the effects of subthreshold vibrotactile random noise stimulation on sensorimotor function, participants were asked to perform grasp movement tasks during random noise stimulation delivered to the volar and dorsal wrist. We set three intensity conditions of the vibrotactile random noise: 0%, 60%, and 120% of the sensory threshold (Noise 0%, Noise 60%, and Noise 120% conditions). In the grasp movement task, the distance between the thumb and index finger was recorded while the participant attempted to grasp a target object, and the smoothness of the grasp movement was quantified by calculating normalized jerk in each experimental condition. The experimental data were compared using two-way repeated-measures analyses of variance with two binary factors: experimental condition (Noise 0%, 60%, 120%) × group (Healthy controls, CIPN patients).Results The smoothness of the grasp movement was only improved in the Noise 60% condition without exacerbating numbness/tingling in CIPN patients and healthy controls. Conclusions The current study suggested that the development of treatment devices using stochastic resonance can improve sensorimotor function for CIPN patients.Trial registration UMIN Clinical Trials Registry（UMIN-CTR）No. UMIN000024776https://rctportal.niph.go.jp/s/detail/um?trial_id=UMIN000024776#

Seated Virtual Reality-Guided Exercise Improved Gait in a Postoperative Hallux Valgus Case

Virtual reality (VR)-guided exercise therapy using mediVR KAGURA has been reported to improve gait function by extending the arm to spatial targets while sitting. We aimed to investigate toe and trunk–pelvic function and plantar sensation during gait in a postoperative patient with hallux valgus. A 60-year-old woman, whose foot deformities had improved 6 months earlier, participated in the study. The exercise therapy interventions were performed twice weekly for 15 min. This study used an A-B-A design: 1-week pre-phase, 3-week intervention phase, and 2-week post-phase. The plantar pressure distribution and thoracic and pelvic displacements during gait were recorded at the end of each phase. The tactile pressure thresholds of the foot were determined before and after each exercise. The maximum force and impulse under the hallux increased after the intervention. The sensory threshold of the hallux was reduced. The amplitude of the thoracic and pelvic displacement was shortened in lateral and extended in the vertical and progressional directions after the intervention. We found that a 3-week VR-guided exercise improved toe function, plantar sensation, and postural adjustment of the trunk and pelvis during gait in a patient who had undergone surgery for hallux valgus, and the effects continued for 2 weeks.

Electroacupuncture modulates cortical excitability in a manner dependent on the parameters used

Introduction: There is evidence that electroacupuncture (EA) acts through the modulation of brain activity, but little is known about its influence on corticospinal excitability of the primary motor cortex (M1). Objective: To investigate the influence of EA parameters on the excitability of M1 in healthy individuals. Methods: A parallel, double blind, randomized controlled trial in healthy subjects, evaluating the influence of an EA intervention on M1 excitability. Participants had a needle inserted at LI4 in the dominant hand and received electrical stimulation of different frequencies (10 or 100 Hz) and amplitude (sensory or motor threshold) for 20 min. In the control group, only a brief (30 s) electrical stimulation was applied. Single and paired pulse transcranial magnetic stimulation coupled with electromyography was applied before and immediately after the EA intervention. Resting motor threshold, motor evoked potential, short intracortical inhibition and intracortical facilitation were measured. Results: EA increased corticospinal excitability of M1 compared to the control group only when administered with a frequency of 100 Hz at the sensory threshold ( p < 0.05). There were no significant changes in the other measures. Conclusion: The results suggest that EA with an intensity level at the sensorial threshold and 100 Hz frequency increases the corticospinal excitability of M1. This effect may be associated with a decrease in the activity of inhibitory intracortical mechanisms. Trial registration number: U1111-1173-1946 (Registro Brasileiro de Ensaios Clínicos; http://www.ensaiosclinicos.gov.br/ )

Comparison of subjective peripheral sensation, F-waves, and somatosensory evoked potentials in response to a unilateral pinch task measured on the contractile and non-contractile sides

Depression of sensory input during voluntary muscle contractions has been demonstrated using electrophysiological methods in both animals and humans. However, the association between electrophysiological responses of the sensory system and subjective peripheral sensation (SPS) during a voluntary muscle contraction remains unclear. Our aim in this study was to describe the changes in SPS, spinal α-motoneuron excitability (F-wave to M-wave amplitude), and somatosensory evoked potentials (SEPs) during a unilateral pinch-grip task. Outcome variables were measured on the side ipsilateral and contralateral to the muscle contraction, and at rest (control). Participants were 8 healthy men, 20.9±0.8 years of age. The isometric pinch-grip task was performed at 30% of the maximum voluntary isometric force measured for the right and left hand separately. The appearance rate of the F-wave during the task was significantly higher for the ipsilateral (right) hand than for the contralateral (left) hand and control condition. Although there was no difference in F-wave latency between hands and the control condition, the amplitude of the F-wave was significantly higher for the ipsilateral (right) hand than for the contralateral (left) hand and the control condition. There was no difference in the amplitude of the SEP at N20. However, the amplitude at P25 was significantly lower for the ipsilateral (right) hand than for the contralateral (left) hand and the control condition. The accuracy rate of detecting tactile stimulation, evaluated for 20 repetitions using a Semmes–Weinstein monofilament at the sensory threshold for each participant, was significantly lower during the pinch-grip task for both the ipsilateral (right) and contralateral (left) hand compared to the control condition. Overall, our findings show that SPS and neurophysiological parameters were not modulated in parallel during the task, with changes in subjective sensation preceding changes in electrophysiological indices during the motor task. Our findings provide basic information on sensory-motor coordination.

The threshold of awareness as an empirical given and as a logical inevitability

The nature of the sensory threshold and approaches to solving the threshold problem in psychophysics are discussed. There were presented experimental results, empirical facts that do not fully correspond to existing psychophysical theories and do not receive an explanation in line with modern approaches. It was concluded that the explanation of the thresholds without description of the participation of consciousness raises doubts. A new look at the nature of thresholds is proposed, in which the threshold is considered as an inevitable consequence of the processes of classification and categorization. Due to the fact that the operations of identification of the non-identical and discernment of the indiscernible are mandatoryin the act of cognition, a zone is formed, within which objectively different elements are identified in consciousness andrelate to the same class. This zone exists across the entire spectrum of cognitive tasks, including detection and discrimination. Thresholds fix the boundaries of this zone. Thus, the problem of the threshold requires a description of the work of not so physiological as cognitive mechanismsfor its solution.

Intensity dependency of peripheral nerve stimulation in spinal LTP induced by paired associative corticospinal-motoneuronal stimulation (PCMS)

Paired associative corticospinal-motoneuronal stimulation (PCMS) induces plasticity at synapses between corticospinal tracts (CSTs) and spinal motoneurons (SMs). We investigated the effects of peripheral nerve electrical stimulation (PNS) intensity on PCMS-induced plasticity. PCMS consisted of 180 paired stimuli of transcranial magnetic stimulation (TMS) over the left primary motor cortex with PNS on the right ulnar nerve at the wrist. We compared effects induced by different PNS intensities: supramaximal, twice and three times sensory threshold intensities. For evaluating efficacy of the synapse between CSTs and SMs, single-pulse TMS was delivered at cervicomedullary junction level, and cervicomedullary motor-evoked potentials (CMEPs) were recorded from the right first-dorsal interosseous muscle before and after PCMS. PCMS with the supramaximal PNS intensity increased CMEP amplitude. The facilitatory effect of PCMS with the supramaximal PNS was larger than those of PCMS with weaker PNS intensities. Sham TMS with the supramaximal PNS showed no CMEP changes after the intervention. PNS intensity of PCMS influences the magnitude of synaptic plasticity induction between the CSTs and SMs at the spinal level, and the supramaximal intensity is the best for induction of long-term potentiation-like effects. The PNS intensity may influence the number of activated SMs by axonal backpropagating pulses with PNS which must overlap with descending volleys induced by TMS.

Effect of Biofeedback Therapy during Temporary Stoma Period in Rectal Cancer Patients: A Prospective Randomized Trial

Background: This prospective randomized controlled study was designed to evaluate the effect of biofeedback therapy (BFT) during temporary stoma period to prevent defecation dysfunction after sphincter-preserving surgery (SPS). Methods: Following SPS with temporary stoma, patients were divided according to whether (BFT group) or not (Control group) they received BFT. BFT was performed once or twice a week during the temporary stoma period. Kegel exercise were advised to all the patients. Subjective defecation symptoms were evaluated according to Cleveland Clinic Incontinence Score (CCIS) as primary outcome at 12 months postoperatively. Manometric data of five time-points were also analyzed. Results: Twenty-one patients in the BFT group and 23 patients in the control group received anorectal physiologic testing. The incidence of CCIS of more than 9 points, which is the primary end point in this study, was not statistically different between BFT group and control group (p = 1.000). The liquid stool incontinence in the BFT group showed a better tendency (p = 0.06) at 12 months post-SPS. Time-dependent serial changes in maximal sensory threshold (Max RST) was significantly different between the BFT and control groups (p = 0.048). Also, the change of mean resting pressure (MRP) tended to be more stable in the BFT group (p = 0.074). Conclusions: The BFT in the period of temporary stoma may be related to liquid stool incontinence at 12 months post-SPS and lead to stable MRP and better Max RST. Therefore, BFT during temporary stoma might be helpful for preventing and minimizing defecation dysfunction in high risk patients after SPS, NCT01661829).

Data Statistics in Volatile Analysis by Accurate HS-SPME-GC/MS Measurement and Calculation

The volatile flavor compound in oil is an important indicator of quality which is widely used in the industry to assess the commercial value of oil. The volatile compounds of moringa seed oil were investigated by HS-SPME-GC/MS. The results showed that 52 volatile compounds were identified in moringa seed oil, including 12 hydrocarbons (20.66%),3 acids (23.99%),8 alcohols (8.28%),2 esters (2.61%),8 aldehydes (14.58%),2 ketones (0.82%),7 phenols (6.25%) and 10 heterocyclics (8.74%). Due to the low sensory threshold and high relatively content of aldehydes, aldehydes is one of the mainly factors to affect the flavor of moringa seed oil.