Changes In Sensory Function Research Articles

LATIHAN KESEIMBANGAN DENGAN METODE LEE SILVERMAN VOICE TREATMENT (LSVT) BIG PADA LANSIA

Based on the period of life, someone entering old age will experience many setbacks. This setback will be faced with various kinds of health problems. These health problems occur because elderly people experience various kinds of functional changes resulting from a decrease in physiological and psychological functions which have an impact on changes in sensory function, neurological, cognitive and musculoskeletal systems. With the neurological changes and musculoskeletal changes that occur in the elderly, this will result in an inability to control balance, resulting in slow movements, increasing the risk of falls, which ultimately disrupts daily activities. This community service activity was carried out through a group approach at the elderly posyandu in Tempuran Village, Bolon, Colomadu Karanganyar using the balance training method with the LSVT BIG method starting from pretest, intervention, posttest. Based on hypothesis testing using the Paired Sample T-Test, a significance value of 0.000 (p<0.005) was obtained, which means that LCVY BIG balance training has an effect on improving the balance of elderly people in carrying out daily activities.

A randomized phase III clinical trial of acupuncture for chemotherapy-induced peripheral neuropathy treatment (ACT).

TPS12151 Background: Chemotherapy-induced peripheral neuropathy (CIPN) is a common and potentially dose-limiting side effect of neurotoxic chemotherapy among people who experience cancer, presenting pain, numbness, tingling, and motor weakness. CIPN worsens quality of life and disrupts active treatment regimens. Currently, duloxetine is the only ASCO-recommended painful CIPN treatment after chemotherapy completion. Still, it has undesirable side effects, i.e., fatigue, sleep disturbance, and digestive symptoms, posing a pressing need for well-tolerated, evidence-based interventions. Our pilot study demonstrated the feasibility and preliminary efficacy of acupuncture in relieving CIPN pain. Based on that, we developed the ACT trial to evaluate the effect of acupuncture on improving pain and other related symptoms among cancer survivors with CIPN pain. Methods: ACT is a prospective phase III multicenter, parallel two-arm randomized clinical trial at Dana-Farber Cancer Institute (DFCI) and Memorial Sloan Kettering Cancer Center (MSK) (ClinicalTrials.gov Identifier: NCT04917796). ACT aims to determine the efficacy of an eight-week electroacupuncture (EA) treatment vs. sham acupuncture (SA) on improving CIPN symptoms severity in cancer survivors. We plan to enroll 250 participants to detect an effect size of at least 0.45 for the primary pain outcome at 12 weeks post-randomization between EA vs. SA, with 80% power and a 1% Type I error rate, assuming a 10% loss to follow-up. Major eligibility criteria include 1) adults who have no evidence of disease or stable diseases, 2) who have completed neurotoxic chemotherapy such as platinum agents, taxanes, vinca alkaloids, and bortezomib at least three months before enrollment, and 3) who have a clinical diagnosis of CIPN with moderate to severe pain, defined as a score of at least four on the Brief Pain Inventory (BPI) average pain item. We randomly allocate participants to receive ten real or sham acupuncture treatments over eight weeks at two centers and their regional clinics. Aside from patient-reported outcome measures (i.e., BPI, Functional Assessment of Cancer Therapy/Gynecologic Oncology Group-Neurotoxicity, EORTC Quality of Life Questionnaire-CIPN 20), we conduct quantitative sensory testing to assess changes in sensory function. The primary study endpoint is week 12, and the secondary study endpoint is week 24. Progress: 1) We are currently transitioning this trial to a multicenter trial, with DFCI being the coordinating center and MSK a subsite; 2) As of January 18, 2024, a total of 133 of the planned 250 participants have been enrolled; 3) The DSMB last reviewed the trial in December 2023, and suggested that the trial continue as planned at MSK. We anticipate initiating participant enrollment at DFCI in February 2024. Accrual completion is expected by December 2024. Clinical trial information: NCT04917796 .

A randomized phase III clinical trial of yoga for chemotherapy-induced peripheral neuropathy treatment (YCT).

TPS12152 Background: Chemotherapy-induced peripheral neuropathy (CIPN) is common and debilitating among cancer survivors receiving neurotoxic chemotherapy, which can cause functional disabilities and significantly increase the risk of falls. There are limited approaches to managing CIPN symptoms and related functional limitations. Our pilot study demonstrated yoga therapy's feasibility and preliminary efficacy in improving CIPN pain and functional outcomes. We developed the YCT trial to assess the effect of yoga therapy on improving pain and balance symptoms among cancer survivors with CIPN pain. Methods: YCT is a prospective phase III multicenter, parallel three-arm randomized clinical trial at Dana-Farber Cancer Institute (DFCI) and Memorial Sloan Kettering Cancer Center (MSK) (ClinicalTrials.gov Identifier: NCT05121558). YCT aims to determine the efficacy of an eight-week yoga treatment vs. education control (EC) vs. usual care (UC) in improving CIPN pain and balance in cancer survivors. We plan to enroll and randomize 268 participants (2:1:1) to yoga, EC, and UC groups to detect an effect size of at least 0.48 for the primary pain outcome at eight weeks post-randomization between yoga vs. EC, with 80% power and a 2.5% Type I error rate, assuming 12% attrition by week 8 and 20% attrition by week 24. Major eligibility criteria include 1) adults who have no evidence of disease or stable diseases, 2) who have completed neurotoxic chemotherapy such as platinum agents, taxanes, vinca alkaloids, and bortezomib at least three months before enrollment, 3) who have a clinical diagnosis of CIPN with moderate to severe pain, defined as a score of at least four on the Brief Pain Inventory (BPI) average pain item, and 4) who experience self-identified CIPN balance difficulty. Eligible subjects in the yoga arm will receive hourly gentle therapeutic yoga classes taught by protocol-trained oncology yoga instructors, twice weekly for eight weeks, and practice home-based yoga. Subjects in the EC arm will receive hourly education classes taught by protocol-trained healthcare instructors twice weekly for eight weeks. Subjects in the UC arm will continue usual care for eight weeks. We offer free yoga sessions for participants in control groups after study completion. Aside from patient-reported outcome measures (i.e., BPI, FACT/GOG-Ntx, QLQ-CIPN 20), we measured functional improvements by functional reach, timed up-and-go, and chair-to-stand tests. We also conducted quantitative sensory testing to assess changes in sensory function. Progress: 1) We are transitioning this trial to a multicenter trial, with DFCI being the coordinating center and MSK a subsite; 2) As of January 18, 2024, 104 of the planned 268 participants have been enrolled. We anticipate initiating participant enrollment at DFCI in February 2024. Anticipated accrual completion: March 2025. Clinical trial information: NCT05121558 .

Depth of resection predicts loss of tongue tip sensation after partial glossectomy in oral tongue cancer: A pilot study

Objective(s)To characterize the change in sensory function following partial glossectomy for oral tongue cancer (OTC) and to identify predictors of loss of tongue-tip sensation (LoTTS). Materials and methodsPatients with at least three months follow-up after partial glossectomy for primary OTC were included. All patients underwent a qualitative tongue sensation assessment and an objective tongue sensory exam of the native tongue tip. Additional details regarding the oncologic resection, surgical reconstruction, and pathological stage were collected. Multiple linear and logistic regressions were used for statistical analysis. ResultsSixty-four patients were enrolled, including 34 (53%) men with a median age of 65 at enrollment. Ten (15%) patients reported LoTTS. Increased depth of resection (DOR) was an independent predictor of LoTTS on multivariate analysis, with an increased risk at a threshold of 1.3 cm. LoTTS was also associated with worse subjective quality of life and perceptive speech performance in our qualitative tongue assessment. ConclusionsIn this pilot study, we found that DOR is a critical prognostic factor in predicting post treatment function. Patients with an increased DOR, particularly above 1.3 cm, are at greatest risk of LoTTS and associated morbidity. These findings may be used to predict post-operative sensory deficits, manage patients’ expectations, and optimize the reconstructive approach. Future studies are needed to validate and replicate our results.

Ontogenetic shifts in olfactory rosette morphology of the sockeye salmon, Oncorhynchus nerka.

Sockeye salmon, Oncorhynchus nerka, are anadromous, semelparous fish that breed in freshwater-typically in streams, and juveniles in most populations feed in lakes for 1 or 2years, then migrate to sea to feed for 2or 3 additional years, before returning to their natal sites to spawn and die. This species undergoes important changes in behavior, habitat, and morphology through these multiple life history stages. However, the sensory systems that mediate these migratory patterns are not fully understood, and few studies have explored changes in sensory function and specialization throughout ontogeny. This study investigates changes in the olfactory rosette of sockeye salmon across four different life stages (fry, parr, smolt, and adult). Development of the olfactory rosette was assessed by comparing total rosette size (RS), lamellae number, and lamellae complexity from scanning electron microscopyimages across life stages, as a proxy for olfactory capacity. Olfactory RS increased linearly with lamellae number and body size (p < .001).The complexity of the rosette, including the distribution of sensory and nonsensory epithelia and the appearance of secondary lamellar folding, varied between fry and adult life stages. These differences in epithelial structure may indicate variation in odor-processing capacity between juveniles imprinting on their natal stream and adults using those odor memories in the final stages of homing to natal breeding sites. These findings improve our understanding of the development of the olfactory system throughout life in this species, highlighting that ontogenetic shifts in behavior and habitat may coincide with shifts in nervous system development.

Differences and Similarities in Spontaneous Activity Between Animal Models of Cancer-Induced Pain and Neuropathic Pain.

BackgroundClinical data on cancer-induced pain (CIP) demonstrate widespread changes in sensory function. It is characterized in humans not only by stimulus-invoked pain, but also by spontaneous pain. In our previous studies in an animal model of CIP, we observed changes in intrinsic membrane properties and excitability of dorsal root ganglion (DRG) sensory neurons corresponding to mechanical allodynia and hyperalgesia, of which abnormal activities of Aβ-fiber sensory neurons are consistent in a rat model of peripheral neuropathic pain (NEP).ObjectiveTo investigate whether there are related peripheral neural mechanisms between the CIP and NEP models of spontaneous pain, we compared the electrophysiological properties of DRG sensory neurons at 2–3 weeks after CIP and NEP model induction.MethodsCIP models were induced with metastasis tumour-1 rat breast cancer cells implanted into the distal epiphysis of the femur. NEP models were induced with a polyethylene cuff implanted around the sciatic nerve. Spontaneous pain in animals is measured by spontaneous foot lifting (SFL). After measurement of SFL, the animals were prepared for electrophysiological recordings of spontaneous activity (SA) in DRG neurons in vivo.ResultsOur data showed that SFL and SA occurred in both models. The proportion of SFL and SA of C-fiber sensory neurons in CIP was more significantly increased than in NEP models. There was no difference in duration of SFL and the rate of SA between the two models. The duration of SFL is related to the rate of SA in C-fiber in both models.ConclusionThus, SFL may result from SA activity in C-fiber neurons in CIP and NEP rats. The differences and similarities in spontaneous pain between CIP and NEP rats is related to the proportion and rate of SA in C-fibers, respectively.

Loss of Enrichment Induces Widespread Muscle Mechanical Hypersensitivity and Enhances Pain Related Behaviors after Ischemia with Reperfusion Injury via Macrophage Dependent Mechanisms

The development of chronic musculoskeletal pain is frequently associated with the presence of high levels of psychological stress. Multiple animal studies have shown that a variety of stress paradigms are effective at inducing deep tissue hyperalgesia and enhanced behavioral responses to subthreshold stimuli or injury. Nevertheless, the mechanisms behind stress-induced hyperalgesia are not clearly understood. Many of the current paradigms induce stress in rodents using physical stimuli that are known to induce changes in sensory function, such as repeated cold exposure or electrical shock. Non-invasive strategies to induce stress in animal models may uncover new mechanisms that drive stress related hyperalgesia. To address this issue, our lab has adapted a stress paradigm that utilizes environmental enhancement and subsequent loss of enrichment (LOE) to induce stress in mice, paired with fore limb ischemia/reperfusion injury (I/R) as a model of muscle hypersensitivity. After LOE, mice developed prolonged immobility time in a forced swimming test and presented with increased weight gain, suggesting increased stress/anxiety-like behaviors. At baseline (1 week after LOE), the mice also developed a bilateral decrease in mechanical withdrawal thresholds to plantar muscle squeezing, indicating stress related hypersensitivity. Immunohistochemical analysis of the plantar muscles showed increased macrophage infiltration one week after LOE. Mice exposed to LOE and I/R injury displayed a prolonged recovery time, compared to normal housing controls. Systemic ablation of macrophages only during the stress period facilitated the recovery after I/R. Our results suggests that LOE can significantly enhance the development of muscle pain after I/R. Together with our immunocytochemical data, results suggest that macrophages could play a role in the development of pain after LOE. These findings highlight the importance of stress in the development of long-lasting pain and may shed light in potential mechanisms behind chronic widespread muscle pain conditions like fibromyalgia. Grant Support from Anesthesia Innovation and Pilot (AIP) Program at Cincinnati Children's Hospital (LFQ) R01NS113965 and R01NS105715 (MPJ).

Combined Effects of Thyroxine with Vitamin B12 on Electrophysiological Changes in Sensory Functions of Sural Nerve of Newly Diagnosed Hypothyroid Female Patients

Background: Combination of thyroxine with vitamin B12 can improve the electrophysiological status of sensory function of sural nerve in newly diagnosed hypothyroid patients. Objectives: To observe the combined effects of thyroxine with vitamin B12 on electrophysiological changes in sensory function of sural nerve of newly diagnosed hypothyroid female. Materials and Methods: This prospective interventional study was carried out in the Department of Physiology, Sir Salimullah Medical College (SSMC) between July’ 2015 to June’ 2016 on 40 newly diagnosed hypothyroid female patients. Among them, 20 hypothyroid patients received only thyroxine (HT-T4) and another 20 hypothyroid patients received combined therapy of thyroxine with vitamin B12 (HT-C) for 90 consecutive days. Nerve conduction parameters of sensory functions of sural nerve were studied to observe the electrophysiological status and vitamin B12 level was also estimated to observe its level by using standard method. The statistical analysis was done by ANOVA test, paired, independent sample ‘t’ test and Chi-square (χ2) test. Results: In this study, latency was significantly decreased, amplitude and NCV were significantly increased in sensory functions of sural nerve of hypothyroid patients after 90 days supplementation of combined therapy of thyroxine with vitamin B12 in comparison to those of their pre-supplemented state and also to those of patients with only thyroxine treatment. Conclusion: The present study revealed the combination of thyroxine with vitamin B12 can reduce the symptoms of hypothyroid and accelerate the nerve conduction velocity of sensory functions of sural nerve more efficiently than the treatment with thyroxine alone. KYAMC Journal. 2022;12(04): 208-212

Identifying Sensory Preferences in People with Changes in Cognition: The SPACE Tool

ABSTRACT People with changes in cognition and changes in sensory function often feel uncomfortable in hospital and residential care home environments. Understanding the person’s sensory preferences and aversions is important in providing high-quality care but current assessments have limitations. Our objective was to develop a tool to identify the sensory preferences and aversions of people experiencing cognitive changes while staying in hospital or residential care homes. The working group developed a tool comprising 11 items, which was named the “Sensory Preferences and Aversions questionnaire for the Care of older adults with dementia in residential Environments” (SPACE) tool. The tool was administered with 56 people with cognitive changes (mean age 78, mean MMSE score 16/30). Data elicited from the tool revealed the varied preferences of individuals, which demonstrates the importance of eliciting this information. For example, while 82% of participants liked listening to music, the remainder did not. Information elicited from the tool was useful in guiding care planning including identifying activities that may be of interest to the person. It was able to effectively elicit information about preferences, aversions, and strategies that could be applied when the person became distressed.

Age-Related Changes in the Response of Finger Skin Blood Flow during a Braille Character Discrimination Task.

We hypothesized that age-related changes in sensory function might be reflected by a modulation of the blood flow response associated with tactile sensation. The aim of the present study was to clarify how the blood flow response of the fingers during concentrated finger perception is affected by aging. We measured the tactile-pressure threshold of the distal palmar pad of the index finger and skin blood flow in the finger (SBF) during Braille reading performed under blind conditions in young (n = 27) and older (n = 37) subjects. As a result, the tactile-pressure threshold was higher in older subjects (2.99 ± 0.37 log10 0.1 mg) than in young subjects (2.76 ± 0.24 log10 0.1 mg) (p < 0.01). On the other hand, the SBF response was markedly smaller in older subjects (−4.9 ± 7.0%) than in young subjects (−25.8 ± 15.4%) (p < 0.01). Moreover, the peak response arrival times to Braille reading in older and young subjects were 12.5 ± 3.1 s and 8.8 ± 3.6 s, respectively (p < 0.01). A decline in tactile sensitivity occurs with aging. Blood flow responses associated with tactile sensation are also affected by aging, as represented by a decrease in blood flow and a delay in the reaction time.

頚椎椎弓形成術前後における知覚・運動機能， 心理面および患者立脚型評価の経時的変化

頚椎椎弓形成術前後における知覚・運動機能， 心理面および患者立脚型評価の経時的変化

Doxepin prevents the Expression and Development of Paclitaxel-Induced Neuropathic Pain.

Background:Peripheral neurotoxicity is a common side effect of many anticancer chemotherapy drugs, including paclitaxel. Peripheral neurotoxicity may present as changes in sensory function and mild paresthesia that, in turn, can lead to alleviation of the prescribed dose of the medication. The aim of this study was to evaluate the effectiveness of acute and chronic doxepin administration on development and expression of neuropathic pain during the treatment of cancer with paclitaxel.Materials and Methods:Neuropathic pain was induced in mice by paclitaxel (2 mg/kg, intraperitoneally [i.p.,] once daily from day 1 to day 5) that caused mechanical and cold allodynia. Doxepin was administrated every day from day 6 to 10 (10 and 15 mg/kg i.p.). Mechanical and cold allodynia was evaluated on day 11 of the experiment in both the test and the control group.Results:Daily administration of doxepin (2.5, 5, and 10 mg/kg i.p.) from day 1 to 5 significantly inhibited the development of cold and mechanical allodynia. As well doxepin administration (5 and 10 mg/kg i.p.) from the 6th day, to 10th day significantly inhibited cold and mechanical allodynia expression. To address the concerns associated with the effectiveness of chemotherapy agents on the tumor, we evaluated paclitaxel cytotoxicity effect in combination with doxepin. Our observations indicate that doxepin even at high concentrations (1 and 10 μg/ml) does not interfere with the cytotoxic effect of paclitaxel (0.05 μg/ml).Conclusions:These results indicate that doxepin, when administered during chemotherapy, can prevent the development and expression of paclitaxel-induced neuropathic pain.

Progress in clinical trials of cell transplantation for the treatment of spinal cord injury: how many questions remain unanswered?

Spinal cord injury can lead to severe motor, sensory and autonomic nervous dysfunctions. However, there is currently no effective treatment for spinal cord injury. Neural stem cells and progenitor cells, bone marrow mesenchymal stem cells, olfactory ensheathing cells, umbilical cord blood stem cells, adipose stem cells, hematopoietic stem cells, oligodendrocyte precursor cells, macrophages and Schwann cells have been studied as potential treatments for spinal cord injury. These treatments were mainly performed in animals. However, subtle changes in sensory function, nerve root movement and pain cannot be fully investigated with animal studies. Although these cell types have shown excellent safety and effectiveness in various animal models, sufficient evidence of efficacy for clinical translation is still lacking. Cell transplantation should be combined with tissue engineering scaffolds, local drug delivery systems, postoperative adjuvant therapy and physical rehabilitation training as part of a comprehensive treatment plan to provide the possibility for patients with SCI to return to normal life. This review summarizes and analyzes the clinical trials of cell transplantation therapy in spinal cord injury, with the aim of providing a rational foundation for the development of clinical treatments for spinal cord injury.

Changes in Sensory Functions in Response to Living in an Extreme Underwater Saturation Environment

The present challenges of long duration spaceflight and other missions in extreme environments include changes of sensory functions, including vision impairment and changes in taste perception. In order to monitor and improve astronaut health and performance during long duration spaceflight and future spaceflight missions we studied sensory functions in response to living in an extreme environment during the NASA Extreme Environment Mission Operation (NEEMO) 23. The Aquarius Reef Base is located at 20 m (66 ft) with 2.6 atm (air) pressure inside the habitat, while levels of CO2 are elevated similarly to the International Space Station.This study assessed the changes in visual acuity and taste perception in 6 NEEMO 23 subjects (2 males, 4 females) 1 day before the mission, during the mission at half time and 1 day post mission. Visual changes were assessed using the NIH Toolbox protocol, while changes in taste perception were measured using solutions containing concentrations of either salty, sweet and bitter flavors in three different concetrations on the side of the tongue and in full mouth.We observed a trend of decreased salty and bitter taste sensation in the habitat and post mission, compared to baseline, while the sweet taste sensation did not change. When testing the full mouth, the salty taste sensation significantly decreased post mission, compared to baseline at low or medium concentration. Bitter taste sensation significantly decreased at low concentration in habitat and post mission, compared to baseline. At medium concentration the bitter taste sensation significantly decreased post mission, compared to baseline and in‐habitat, while at high concentration it significantly decreased post mission, compared to baseline. There was a signifcant reduction in the Overall Raw and in Overall Uncorrected Vision Scores between baseline and post mission indicating a significant reduction in visual acuity during the 9 days mission that was not restored immediately after the mission.Living in a saturation environment decreases certain sensory modalities that may persist for an unknown length of time after the exposure. Diminished sensitivity to taste can alter nutritional status and chemosensory changes may also relate to space sickness, stress and psychological factors, while changes in vision may impair operational tasks. These data indicate that mitigation strategies need to be developed and tested in space analog environments.Support or Funding InformationKetone Technologies LLC provided partial funding for the study. SIFT provided partial salary for CA.

Current aspects of vertigo and dizziness in advanced age

Vertigo and dizziness in advanced age are common complaints in daily clinical practice. The otorhinolaryngologist holds a central position in the differential diagnostic clarification. Age-related disorders (e.g. benign positional vertigo, presbyvestibulopathy, otholith functional disorders) arise due to a physiological, individually distinct and objectively detectable reduction in the sensitivity of sensory and extrasensory elements of the vestibular system. They may reach pathological significance if these dysfunctions affect the physical and emotional well-being (e.g. gait disturbances and falls with subsequent morbidity). Disorders accompanying aging (e.g. neurological, cardiovascular or psychiatric) can occur simultaneously with age-related changes in sensory function. The identification, especially with respect to the risk of falling in older people and the development of individual therapeutic strategies is an interdisciplinary task. Besides a causative therapy, strength, coordination and balance training contribute to the treatment of equilibrium disorders and falls from the perspective of evidence-based medicine.

The Association between Self-Reported Sensory Impairment and Cognitive Function among Korean Older Adults: Results from the 2017 National Survey of the Living Conditions and Welfare Needs of Older Koreans

본 연구는 한국 노인이 주관적으로 인식하는 감각장애와 인지기능 간의 관계 조사이다. 연구방법은 2017년 노인실태조사 자료를 활용하여 65세 이상 10,082명에 대한 주관적 감각장애에 대한 평가 자료와 MMSE-DS를 통한 인지기능 간 관계를 위계적 다중회귀분석과 로지스틱 회귀분석을 실시하였다. 연구결과 시력, 청력, 구강 기능에 대해 주관적 불편감을 보고할수록 인지기능 감소의 위험이 높게 나타났다. 또한 청력, 구강에 대한 불편감은 치매로 이어질 가능성이 높음을 발견하였다. 특히 다른 감각기능에 비해 청력 불편감이 치매의심 집단의 인지기능과 상관관계가 가장 높은 것으로 나타났다. 본 연구의 결과는 노인의 감각기능을 정부 차원에서 관리할 필요성이 있으며, 노인 스스로 감각기능의 신체적 변화를 지각하고 평가하기 위한 도구를 개발할 필요가 있음을 제안한다. 아울러 노인의 건강 증진을 위한 구체적인 방안을 위한 연구가 필요하다.The present study aims to examine the relationship between self-reported sensory impairment and cognitive function among older adults in Korea. Drawn from the 2017 Survey of Living Conditions and Welfare Needs Korean Older Persons, a total of 10,082 adults aged 65 and over were included in analyses. Results from hierarchial multiple regression analysis show that those who reported greater subjective discomfort about vision, hearing, and oral function were more likely to have poor cognitive function. Results from hierarchial logistic regression analysis show. Results from logistic regression analysis show that having hearing and oral discomfort increased the a risk for dementia. Findings suggest that it is necessary to manage sensory function of the elderly at the government level and to develop self-evaluation tools to monitor changes in sensory function for older adults. Future research should target finding effective ways to improve health of older adults.

Acute Vibration Induces Peripheral Nerve Sensitization in a Rat Tail Model: Possible Role of Oxidative Stress and Inflammation

Prolonged occupational exposure to hand-held vibrating tools leads to pain and reductions in tactile sensitivity, grip strength and manual dexterity. The goal of the current study was to use a rat-tail vibration model to determine how vibration frequency influences factors related to nerve injury and dysfunction. Rats were exposed to restraint, or restraint plus tail vibration at 62.5 Hz or 250 Hz. Nerve function was assessed using the current perception threshold (CPT) test. Exposure to vibration at 62.5 and 250 Hz, resulted in a reduction in the CPT at 2000 and 250-Hz electrical stimulation (i.e. increased Aβ and Aδ, nerve fiber sensitivity). Vibration exposure at 250 Hz also resulted in an increased sensitivity of C-fibers to electrical stimulation and thermal nociception. These changes in nerve fiber sensitivity were associated with increased expression of interleukin (IL)-1β and tumor necrosis factor (TNF)-α in ventral tail nerves, and increases in circulating concentrations of IL-1 β in rats exposed to 250-Hz vibration. There was an increase in glutathione, but no changes in other measures of oxidative activity in the peripheral nerve. However, measures of oxidative stress were increased in the dorsal root ganglia (DRG). These changes in pro-inflammatory factors and markers of oxidative stress in the peripheral nerve and DRG were associated with inflammation, and reductions in myelin basic protein and post-synaptic density protein (PSD)-95 gene expression, suggesting that vibration-induced changes in sensory function may be the result of changes at the exposed nerve, the DRG and/or the spinal cord.

The effect of disbudding age on healing and pain sensitivity in dairy calves

Hot-iron disbudding, a husbandry procedure performed in dairy calves in which horn bud growth is prevented through tissue cauterization, produces severe burns. Little is known about how long pain persists following disbudding or factors, such as age at the time of disbudding, that may influence animal welfare outcomes. Our objectives were (1) to evaluate whether disbudding age mediates healing, pain sensitivity, and weight gain in calves disbudded near birth (3 d) compared with at a later age (35 d); and (2) to examine how long wounds are sensitive during healing. Forty-eight calves were disbudded or sham-disbudded at 3 or 35 d of age (n = 12/treatment). We assessed pain sensitivity with a pressure algometer on d 3 and 7 after disbudding and then weekly thereafter until the wound had re-epithelialized. Sensitivity was measured at the lateral and caudal edges of each wound, as well as on the rump to test for systemic changes in sensory function. We evaluated healing by scoring the presence of 7 tissue types in the wound bed: attached necrotic tissue, detached necrotic tissue, burns outside the necrotic ring, exudate, granulation, crust, and epithelium. Tissue scores, surface temperature, and girth circumference as an estimate of weight gain were measured twice weekly until the wound had re-epithelialized. Disbudded tissue was more sensitive than nondisbudded tissue for at least 3 wk, after which time the sham calves were removed from the study to be disbudded. Wounds took 62 ± 10 d (mean ± SD) to re-epithelialize and were more painful than new epithelium throughout this time, regardless of whether the procedure occurred at 3 or 35 d of age. The surface temperature of disbudding wounds did not differ from that of non-disbudded tissue nor did disbudding affect weight gain at either age. Age at the time of disbudding did not affect latency to re-epithelialize or wound sensitivity. However, rump sensitivity was greater in calves disbudded at 3 versus 35 d of age on d 28, 42, and 56 after disbudding, in agreement with other studies showing increased pain sensitivity when painful procedures are performed at an early age. In conclusion, wounds remain painful throughout healing, raising animal welfare concerns about hot-iron disbudding. Performing the procedure near birth does not improve welfare outcomes; rather, some evidence suggests it may produce a generalized long-term increase in pain sensitivity.

Rat model of cancer-induced bone pain: changes in nonnociceptive sensory neurons in vivo.

Clinical data on cancer-induced bone pain (CIBP) suggest extensive changes in sensory function. In a previous investigation of an animal model of CIBP, we have observed that changes in intrinsic membrane properties and excitability of dorsal root ganglion (DRG) nociceptive neurons correspond to mechanical allodynia and hyperalgesia. To investigate the mechanisms underlying changes in nonnociceptive sensory neurons in this model, we have compared the electrophysiological properties of primary nonnociceptive sensory neurons at <1 and >2 weeks after CIBP model induction with properties in sham control animals. Copenhagen rats were injected with 106 MAT-LyLu rat prostate cancer cells into the distal femur epiphysis to generate a model of CIBP. After von Frey tactile measurement of mechanical withdrawal thresholds, the animals were prepared for acute electrophysiological recordings of mechanically sensitive neurons in the DRG in vivo. The mechanical withdrawal threshold progressively decreased in CIBP model rats. At <1 week after model induction, there were no changes observed in nonnociceptive Aβ-fiber DRG neurons between CIBP model rats and sham rats. However, at >2 weeks, the Aβ-fiber low-threshold mechanoreceptors (LTMs) in CIBP model rats exhibited a slowing of the dynamics of action potential (AP) genesis, including wider AP duration and lower AP amplitude compared with sham rats. Furthermore, enhanced excitability of Aβ-fiber LTM neurons was observed as an excitatory discharge in response to intracellular injection of depolarizing current into the soma. After induction of the CIBP model, Aβ-fiber LTMs at >2 weeks but not <1 week had undergone changes in electrophysiological properties. Importantly, changes observed are consistent with observations in models of peripheral neuropathy. Thus, Aβ-fiber nonnociceptive primary sensory neurons might be involved in the peripheral sensitization and tumor-induced tactile hypersensitivity in CIBP.

An Examination of Patellar Tendon Reflex Pre-Motor Conduction Velocity across the Adult Lifespan

It is known that aging is accompanied by a loss in muscle mass and motor units. However, the direct cause for the loss of motor units has not been identified. One possible mechanism could be related to changes in the sensory input motor neurons receive. Therefore, it is important to find objective measures to quantify sensory function that are sensitive to changes with aging. PURPOSE: To determine if the conduction velocity of a patellar tendon reflex is sensitive to aging. METHODS: One hundred and one volunteers participated in this study. Tendon taps were delivered to the patellar tendon of each subject while surface electromyographic (EMG) signals were recorded from the rectus femoris. The pre-motor reflex latency was calculated as the time from the onset of the hammer-strike to the onset of EMG activity. This latency (s) was adjusted for femur length (m) to instead provide a pre-motor conduction velocity (CV; m/s). The subjects were then grouped and averaged into intervals based on age as follows: 18 - 29 yrs. (n = 50), 30 - 39 (n = 10), 40 - 49 (n = 6), 50 - 59 (n = 16), 60 - 69 (n = 13) and > 70 (n = 6). Linear regression was applied across the mean age and pre-motor CV from each interval. RESULTS: Pre-motor CV was negatively related to age (r = - 0.799; p = 0.028). The resulting regression equation was y = -0.1113x + 24.216. The group averaged data as well as the line of best fit are shown in the figure below. CONCLUSION: Our findings show that the conduction velocity of a patellar tendon reflex is significantly related to age. Therefore, this variable may be useful in future studies that wish to track changes in sensory function across age.Figure