神经定量感觉测量

在 19世纪 ,随着神经物理学和各种监测仪器的发展 ,人们开始定量地评估感觉的程度 ,测量各种感觉的阈值 (包括温度觉和振动觉 )、耐受能力 ,并绘制阈上刺激反应曲线。神经物理学的先辈们发现刺激的频率及其他特性是神经电兴奋性的重要参数 ;其研究对定量感觉测量 (ｑｕａｎｔｉｔａｔｉｖｅｓｅｎｓｏｒｙｔｅｓｔｉｎｇ,ＱＳＴ)的发展起重要的推动作用。电子计算机的飞速发展 ,使原本复杂的原理得以应用于临床工作之中。现在 ,人们可方便地借助于电子仪器来自动设定刺激参数 ,采集信号 ,分析结果。近 2 0年来 ,ＱＳＴ愈来愈广泛地应用于科…     

神经定量感觉检查及临床应用

1　理论基础与方法神经定量感觉检查 (ＱＳＴ)作为近二十年才发展起来的检查项目在国外已获得了迅速的发展 ,而我国于近两年才引入该项检查 ,目前国内尚无神经定量感觉检查 (ＱＳＴ)的研究报告。我们知道 ,临床上对于周围神经病的诊断已开展了多种检查技术 ,诸如神经肌电图、诱发电位、Ｆ波、Ｈ反射等等 ,但这些检查都是针对粗神经纤维的 ,而ＱＳＴ则是针对细神经纤维 (Ａδ、Ｃ类 )功能的。相比传统的检查而言 ,ＱＳＴ具有无创性及无任何不舒服的感觉 ,特别适合于监测和长期观察感觉功能[2 ] 。原理 :ＱＳＴ技术主要通过对皮肤的温度觉、冷…     

感觉电流阈值在糖尿病周围神经病变诊断中的临床应用

目的:探讨感觉电流阈值(CPT)在糖尿病周围神经病变(DPN)诊断中的价值.方法:选取符合入选条件的52例2型糖尿病( T2DM)患者和50例健康人的感觉电流阈值.以神经传导速度检查( NCV)为诊断糖尿病周围神经病变的“金标准”,使用X 2检验评价电流感觉阈值的灵敏度、特异度、阳性预测值、阴性预测值及Kappa值.结果:以NCV为标准,电流感觉阈值的灵敏度61.1％,特异度62.5％,阳性预测值78.6％,阴性预测值41.7％,Kappa值0.207.结论:电流感觉阈值能评估个体感觉通路功能,有助于筛查DPN患者.     

定量感觉测定对有感觉异常的焦虑症患者的研究

目的：观察定量感觉测定（QST）在有感觉异常的焦虑症患者中的应用价值。方法：用QST检测有主观感觉障碍的20例焦虑症患者和20例正常对照组的感觉阈值,包括四肢的冷觉（CS）、温觉（WS）、冷痛觉（CP）、热痛觉（HP）的值进行分析,并作比较。结果：焦虑症组中的四肢的CP、HP异常较CS、WS更明显,焦虑症组中CS、WS、CP、WP的异常率分别是10％,15％,51％,53％。结论：焦虑组的QST的感觉阈值改变,说明焦虑症所产生的感觉障碍可能与周围和中枢神经敏感性增高有关。     

60例正常人不同部位皮肤的温度觉差异

目的：探讨正常人不同部位皮肤的温度觉阈值的差异性。方法：对60例正常人进行大鱼际肌、食指、脚背皮肤的冷觉、热觉、冷痛觉、热痛觉神经定量感觉测试（QST）并进行比较分析。结果：在冷觉、热觉、热痛觉方面大鱼际肌的感觉比脚更加敏感，而冷痛觉则无明显差异；大鱼际肌皮肤温度觉比食指皮肤更敏感。结论：人体不同部位皮肤的温度觉存在差异性，但同一部位左右两侧相比则差异不明显。     

电流感觉阈值对糖尿病足风险的预测研究

目的应用感觉神经定量检测仪检测糖尿病足患者周围感觉神经,探讨电流感觉阈值(CPT)在糖尿病足发生风险的预测价值。方法测定48例糖尿病足(糖尿病足组)及212例未合并足病的糖尿病患者(非糖尿病足组)的正中神经、腓肠神经于2000Hz、250Hz、5Hz的CPT,并检测患者踝肱指数(ABI)及血糖等代谢指标,记录高血压、冠心病等病史及糖尿病并发症情况。结果与非糖尿病足组患者比较,糖尿病足组患者CPT明显升高,其中5Hz(P<0.01)最为明显;糖尿病足组合并高血压、冠心病、脑梗死、糖尿病肾病、糖尿病视网膜病变的发生率均高于非糖尿病足组(P<0.01);糖尿病足组较非糖尿病足组ABI明显降低,在各分度组差异均有统计学意义(P<0.01)。ABI与5HzCPT及250HzCPT均呈负相关(r=-0.454,P<0.01;r=-0.342,P<0.05)。结论糖尿病神经病变的发生与血管病变有关,ABI低、CPT高的患者糖尿病足较单独ABI低的患者糖尿病足发生风险增加,CPT联合ABI较单独检测ABI对于糖尿病足的发生更加有预测价值。     

感觉定量和神经传导速度联合检测对糖尿病周围神经病的诊断价值

目的:探讨感觉定量检测(QST)、神经传导速度检测(NCV)联合应用对糖尿病(DM)周围神经病(PNP)的诊断价值。方法:对37例DM患者进行常规NCV检测;并且对这37例DM患者和20例正常人进行QST检测。结果:在37例DM患者中,QST异常32例(86％),与对照组比较差异有极显著意义(P<0．001);NCV检测异常23例(62％),与正常值对照差异有极显著意义(P<0．001)。这两种检测方法阳性率对比,差异亦有统计学意义(P<0．05)。结论:NCV可作为DM-PNP的常规检测方法,但NCV仅能反映粗有髓神经纤维的功能,阳性率低,而QST可反映细神经纤维的功能,且操作简便,无创伤,无痛苦,老年人易接受。两种方法联合使用可提高DM患者PNP的检出率,为DM-PNP的诊断提供有力依据,也可作为治疗及预后观察的客观指标。     

带状疱疹后遗神经痛患者的感觉定量测定

目的：研究不同临床表现的带状疱疹后遗神经痛（PHN）的发病机制。方法：用感觉定量分析仪对25例PHN患者的疼痛区及对侧镜象区进行定量感觉测试，并用视觉类比量表评价疼痛的强度。结果：自发性疼痛组（8例）感觉缺失值大于触觉异常性疼痛组（17例）；在触觉异常性疼痛组，感觉缺失程度与疼痛评分成负相关，而在自发性疼痛组，二者间未见显著相关性。结论：触觉异常性疼痛与感觉传入小纤维的活性增高、异常放电有关，而自发性疼痛与脊髓神经元的自发性痫样放电有关。     

糖尿病性周围神经病的定量感觉检查

目的:探讨定量感觉检查(QST)对糖尿病性周围神经病(DPN)诊断的临床应用价值.方法:应用QST仪检测118名正常人与136例DPN病人的冷觉(CS)、热觉(WS)和振动觉(VS)阈值及神经传导速度(NCV).结果:DPN组和单纯糖尿病(DM)组与正常对照组比较,手指和足背QST的CS、WS、VS阈值差异均有统计学意义(P＜0.05).DPN组和单纯DM组之间比较,手指和足背CS、WS、VS阈值差异也有统计学意义(P＜0.05).DPN组和单纯DM组之间比较手指和足背不同部位的CS、WS、VS阈值差异均有显著意义(P＜0.05).DPN组CS、WS、VS的异常率高于运动神经传导速度(MCV)、感觉神经传导速度(SCV)的异常率(P＜0.05),CS、WS的异常率高于VS的异常率(P＜0.05);DPN组患者的MCV、SCV、CS、WS和VS异常率均高于单纯DM组的异常率,其间差异有显著意义(P＜0.01);病程＞5年组的MCV、SCV、CS、WS和VS的异常率均高于病程≤5年组的异常率,其间差异亦有显著意义(P＜0.01);HbAlC正常组和HbAlC异常组MCV、SCV、CS、WS和VS异常率之间比较差异均无统计学意义(P＞0.05).结论:QST能为DPN的早期诊断提供可靠依据,是常规NCV检查的必要补充.     

Symptom‐related changes in current perception threshold of restless legs syndrome

Few studies have investigated the mechanisms responsible for the symptoms of restless legs syndrome (RLS). However, these studies were mainly performed during the asymptomatic period and therefore their findings might not apply to changes in sensory processing that occur during the symptomatic period. The objective of this study was to investigate the function of sensory nerve fibres in RLS patients using the current perception threshold (CPT) test during the daytime and in the presence of symptoms. Ninety‐three patients with RLS and 34 healthy controls were included in the study. RLS patients were further divided into two subgroups, those who were experiencing RLS symptoms during the CPT test (symptom+) and those without symptoms (symptom?). Demographic data, RLS rating scale score and visual analogue scale were collected. Of the 127 enrolled subjects, CPT values were significantly lower in RLS patients than in controls for all three frequencies. Among the control and RLS subgroups (53 symptom+, 40 symptom?), symptom+ patients showed lower CPT values than controls. This finding indicates a relative hyperaesthetic state in the sensory afferents of peripheral nerves in symptom+ patients. There were no significant differences between the symptom? group and controls. The significantly lower CPT values for all three frequencies in symptom+ patients suggest that central sensory processing disturbance of sensory nerve fibres’ input may be involved in the development of symptoms in RLS patients.     

Measurement precision of a portable instrument to assess vibrotactile perception threshold

Summary The objective of the present study was to evaluate the reliability of a modified version of the commercially available Biothesiometer, and to examine vibrotactile perception thresholds with respect to age and gender. A standardized protocol for measuring vibrotactile perception threshold was administered to 80 subjects, once a week over 4 weeks. Inter-session variability was stable (analysis of variance for repeated measures; P>0.05) and correlations were high (Pearson's: 0.87r0.90; P0.001). For sites on both hands and feet, there was a significant increase with age (0.19r ²0.52; P0.001). Five factor analysis of variance model showed that vibrotactile perception threshold was significantly different with stimulus site, age category and gender; no differences were observed with alcohol consumption or smoking status. The findings indicate that the measurements from this device are highly reproducible and sensitive to expected threshold differences with age and gender. The authors attribute this to technical improvements of the original apparatus, rigid adherence to test protocol and maintenance of standard conditions. This type of instrument would be useful in assessing vibrotactile perception loss in occupational health studies.     

Experimental analysis of the human perception threshold of a DC electric field

To study the biological effects of extremely low frequency (ELF) electric fields, a fundamental study is conducted of the human perception threshold of an electric field. The perception threshold is measured with human subjects, and the results are analysed. It is clear that field perception is based on the movement of hair and not on other sensations. Variance in the perception threshold and its causes are investigated. The perception threshold decreases by almost 30% as the relative humidity increases from 50 to 90%. The perception threshold is also dependent on the physical condition (length and density) of the hair and the psychological condition (degree of awareness) of the subject. The dependence on these is much smaller than that on relative humidity. The cause of the gender difference in the threshold is ascribed to the difference in the physical condition of the hair. Through this study, some factors to be taken into account for the safety standard are made clear.     

Experimental analysis of the human perception threshold of a DC electric field

To study the biological effects of extremely low frequency (ELF) electric fields, a fundamental study is conducted of the human perception threshold of an electric field. The perception threshold is measured with human subjects, and the results are analysed. It is clear that field perception is based on the movement of hair and not on other sensations. Variance in the perception threshold and its causes are investigated. The perception threshold decreases by almost 30% as the relative humidity increases from 50 to 90%. The perception threshold is also dependent on the physical condition (length and density) of the hair and the psychological condition (degree of awareness) of the subject. The dependence on these is much smaller than that on relative humidity. The cause of the gender difference in the threshold is ascribed to the difference in the physical condition of the hair. Through this study, some factors to be taken into account for the safety standard are made clear.     

Collateral reinnervation of rat hindlimb skin does not depend on repeated sensory testing

After cutaneous nerve injury there is a tendency for afferents in neighboring cutaneous nerves to reinnervate the adjacent denervated zone. Diamond and collaborators have recently claimed [5, 8] that collateral sprouting of cutaneous afferents in the hindquarter of adult mammals is substantially accelerated by sensory testing (pinching) of the skin. We examined this claim in hindlimb skin of adult rats. All but the most medial part of the foot was rendered anesthetic by ligation and section of the sciatic nerve. The return of mechanosensation by functional spread of the intact saphenous nerve was examined behaviorally. We were unable to detect any effect of repeated sensory testing on this sensory recovery.     

A system for selectively inactivating nerve fibres by a polarising,transient current

Summary A device that provides a versatile and easily controllable means of producing transient current waveforms for the selective inactivation of nerve-fibre groups is described. It is constructed from readily available components, such as integrated circuits and optically coupled isolators. Good separation between A-fibre and C-fibre responses in the rat saphenous nerve has been achieved.     

Simplification of the Research Diagnosis of HIV-Associated Sensory Neuropathy

Abstract

Peripheral neuropathy (PN) is the most common neurological complication of HIV infection,affecting over one third of patients. The research diagnosis of PN is complicated by the need for expensive, time-consuming, and noxious diagnostic tests. We investigated whether nerve conduction studies (NSC) and quantitative sensory tests (QST) provide added value for the diagnosis of PN for research purposes or whether the easily obtainable clinical measures (sensory and motor symptoms, sensitivity to pain and vibration, tendon reflexes, motor function) are sufficient.     

Comparison of heart rate as a non-invasive determinant of anaerobic threshold with the lactate threshold when cycling

Summary In 9 trained athletes and 4 sedentary subjects the anaerobic threshold was assessed on a cycle ergometer, using the deflection point of heart rate in a protocol in which the workload increased by 10 W every 45 s. The workload at which plasma lactate concentration equalled 4 mmol · l^–1 was assessed under steady state conditions on separate occasions. In addition, in 3 subjects the non-invasive anaerobic threshold and the 4 mmol · l^–1 lactate level under steady state conditions were assessed on a treadmill. On the cycle ergometer 6 subjects demonstrated a deflection point in the heart rate record, whereas the others failed to do so. The workload at which heart rate departed from linearity in the progressive protocol did not coincide with the steady state 4 mmol · l^–1 workload but occurred at a higher workload. On the treadmill no deflection in heart rate was observed. It is concluded that in cyclists a deflection in heart rate does not always occur, and when it does, it does not coincide with the anaerobic threshold determined under steady state conditions.     

Measurement of perception threshold to an electric stimulus using a phase-sensitive technique in normal and diabetic subjects

To evaluate the functional state of peripheral sensitivity we measured the perception threshold to an electrical stimulus applied deeply at the level of the lower limbs in both diabetic and nondiabetic patients. The data were obtained using a phase-sensitive technique with a sinusoidal applied voltage at 1592 Hz. The test signal applied through needle electrodes was monitored using a current-to-voltage convertor, the current being considered to have two components, one resistive (I_R) in phase with the voltage V across the electrodes, and the other capacitive (I_c) 90^o out of phase. A significantly (p<0·001) higher perception threshold was found in diabetic patients than in nondiabetic subjects with all three electrical variables measured: I_R, I_C and V.     

Stability of phantom limb phenomena after upper limb amputation: a longitudinal study

Amputees may experience stump pain (SP), phantom limb (PL) sensations, pain, and/or a general awareness of the missing limb. The mechanisms underlying these perceptions could involve nervous system neuroplasticity and be reflected in altered sensory function of the residual limb. Since little is known about the progression of post-amputation sensory phenomena over time, we longitudinally evaluated the stability of, and relationships among: 1) subjective reports of PL sensations, pain, awareness, and SP, 2) stump tactile and tactile spatial acuity thresholds, and 3) use of a functional vs. a cosmetic prosthesis in 11 otherwise healthy individuals with recent unilateral, traumatic upper-extremity amputation. Subjects were evaluated within 6 months and at 1-3 years after amputation. Processing of tactile sensory information from the stump remained stable over the study time period. PL awareness was frequent, stable over time, intense, and occurred with or without PL sensations. Functional prosthetic use correlated with stable vividness of PL awareness whereas subjects who used a cosmetic prosthesis had less vivid PL awareness at follow-up. Initial SP correlated with follow-up SP, the initial PL pain correlated with follow-up PL pain but neither initial nor follow-up SP appear to be related to follow-up PL pain after accounting for initial PL pain intensity. Neither limb temperature nor prosthesis-use correlated with the initial vs. follow-up change in PL pain intensity. These data provide evidence that PL pain described 1-3 years after an amputation is not related in any simple way to peripheral sensory function, SP, or limb temperature; and PL awareness but not PL pain may be influenced by the frequent use of a functional prosthesis.