Correlation of vibratory quantitative sensory testing and nerve conduction studies in patients with diabetes

Monitoring the course of diabetic peripheral neuropathy (DPN) remains a challenge. Besides clinical examination, nerve conduction studies (NCS) and quantitative sensory testing (QST) are the most commonly used methods for evaluating peripheral nerve function in clinical trials and population studies. In this study the correlation between vibratory QST and NCS was determined. Patients (N = 227) with diabetes mellitus participated in this multicenter, single-visit, cross-sectional study. QST of vibration measured with the CASE IV system was compared with a composite score of peroneal motor and tibial motor NCS and with individual attributes of peroneal, tibial, and sural nerves. The correlation between QST and composite score of NCS was 0.234 (Pearson correlation coefficient, P = 0.001). The correlations between QST and individual attributes of NCS ranged from 0.189 to 0.480 (Pearson correlation coefficients, P < 0.001). The low to moderate correlation between QST and NCS suggests that these tests cannot replace each other but are complementary.     

糖尿病患者周围神经传导速度的研究

目的:通过周围神经传导速度(NCV)的研究,早期诊断糖尿病(DM)患者的糖尿病性周围神经病变。方法:应用上海海军医学研究所NDI-200F神经电检诊仪,对DM组95例患者行尺神经、正中神经、胫神经和腓神经运动传导速度(MCV)及尺神经、正中神经、腓肠神经感觉传导速度(SCV)检测与30例健康人组对照。结果:DM组95例, NCV异常率为77.89%(74/95)。共检测665条神经,MCV380条,异常率55.26%,SCV285条,异常率50.88%,差异无显著性意义(P>0.05)。上肢检测380条神经,异常率45.53%,下肢检测285条神经,异常率63.86%,差异有显著性意义(P<0.05)。DM组SCV波幅减低率为53.66%。DM组按病程分为三组,<5年,30例,异常率28.10%;≥5年,31 例,异常率为54.84%;≥10年,34例,异常率74.37%,组间差异均有非常显著性意义(P<0.01)。DM组中29例无周围神经病变症状与体征,NCV异常11例(37.93%)。结论:周围神经传导速度检测不但可以早期诊断糖尿病患者的糖尿病性周围神经病变,而且此方法可靠、简便、无创。     

Ischemia and sensory nerve conduction in diabetes mellitus

Sensory conduction along the median nerve was evaluated during 30 minutes of ischemia in patients with diabetes mellitus. There was abnormal persistence of the sensory evoked potential in 19 of 22 diabetic patients, but not in normal controls, patients with nonmetabolic neuropathies, or 5 of 6 patients with motor neuron diseases. There was an excellent correlation between ischemic resistance and effective control of glucose metabolism, as manifested by Hb A1C levels. These data suggest that abnormal ischemic resistance in diabetes may be the most sensitive indicator of peripheral neural dysfunction even when there are no other electrophysiologic or clinical abnormalities.     

F-wave latency,the most sensitive nerve conduction parameter in patients with diabetes mellitus

In this study we examined the diagnostic sensitivity of minimal F-wave latency, F-wave persistence, motor nerve conduction velocity (MCV), and amplitude of the compound motor action potential (CMAP) of the median, ulnar, tibial, and peroneal nerves, and of sensory conduction velocity (SCV) and sensory nerve action potential (SNAP) amplitude of the sural nerve in 82 diabetic patients. For the median, ulnar, and tibial nerves the Z scores of the minimal F-wave latency were significantly larger than those of the MCV, and for all four motor nerves the Z scores of the minimal F-wave latency were significantly larger than those of the amplitude of the CMAP. The Z scores of the peroneal minimal F-wave latency exceeded those of peroneal MCV, sural SCV, and sural SNAP. F-wave persistence did not differ significantly from the reference values. In conclusion, minimal F-wave latency is the most sensitive measure for detection of nerve pathology and should be considered in electrophysiological studies of diabetic patients. © 1997 John Wiley & Sons, Inc. Muscle Nerve 20: 1296–1302, 1997     

Resistance to ischaemic nerve-fibre block in diabetes mellitus and in mitochondrial encephalomyopathies

Thermal thresholds were measured during ischaemic compression block in the left forearms of 26 healthy subjects, 10 patients with diabetes mellitus and 6 patients suffering from different kinds of mitochondrial disorders. Cold and warm thresholds in the 6 patients with deficiencies in the respiratory chain increased earlier than in normals. When cold perception was impaired, cold stimuli were perceived as warmth and pinprick perception attenuated. In diabetics cold thresholds were less elevated during ischaemic block than in controls. This was paralleled by tingling paraesthesiae in all groups. The findings show that higher resistance to ischaemic nerve-fibre block in diabetes mellitus is not exclusively based on increased anaerobic metabolism.     

Resistance to hypoxic conduction block in sciatic nerves of rats with streptozotocin-induced diabetes mellitus

This study describes the electrophysiological responses of endoneurial preparations derived from rat sciatic nerve to acute hypoxia in vitro. Preparations from control rats exhibited a marked decline in compound action potential (CAP) amplitude coupled with an increase in latency, during 40 minutes exposure to 8% O2. In contrast, preparations from 4 week streptozotocin-diabetic rats showed a greatly reduced decline in CAP amplitude, with an increase in latency. Twice-daily insulin treatment of diabetic rats resulted in a pattern of CAP amplitude decline that initially resembled that of untreated diabetics but by 40 min was similar to controls, with latency again increasing during hypoxia. Nerves were also maintained in 25 mmol/l glucose, rather than the 5 mmol/l glucose of the above studies. Under such conditions the performance of nerves from diabetic rats was unaltered. Nerves from control rats exhibited an initial resistance to hypoxia but by 40 min CAP had declined to values of control rats maintained in 5 mmol/l glucose. An increase in latency during hypoxia was also noted in preparations from control or diabetic rats maintained in 25 mmol/l glucose. The maintenance of CAP amplitude during hypoxia by diabetic preparations is initially related to increased substrate availability, with an additional component that is not related to external glucose levels in vitro, and is absent after insulin treatment of diabetic rats.     

Altered tibial nerve biomechanics in patients with diabetes mellitus

Introduction: Hyperglycemia associated with diabetes mellitus (DM) has adverse impacts on peripheral nerve connective tissue structure, and there is preliminary evidence that nerve biomechanics may be altered. Methods: Ultrasound imaging was utilized to quantify the magnitude and timing of tibial nerve excursion during ankle dorsiflexion in patients with DM and matched healthy controls. Results: Tibial nerve longitudinal excursion at the ankle and knee was reduced, and timing was delayed at the ankle in the DM group. Severity of neuropathy was correlated with larger reductions in longitudinal excursion. Nerve cross‐sectional area was increased at the ankle in the DM group. Conclusions: Larger tibial nerve size within the tarsal tunnel in patients with DM may restrict longitudinal excursion, which was most evident with more severe neuropathy. It is hypothesized that these alterations may be related to painful symptoms during functional activities that utilize similar physiological motions through various biomechanical and physiological mechanisms. Muscle Nerve 50:216–223, 2014     

Rehabilitation after stroke in patients with diabetes mellitus

Diabetes mellitus is not only one of the fundamental risk factors for stroke, but it may also constitute a significant impediment and limitation of rehabilitation process in diabetic patients after stroke. Insufficiently controlled diabetes or insufficient insulin therapy inadequately carried out, especially during the period of acute cerebrovascular complications, may increase the risk of repeated stroke or increase the size of ischaemic area. In patients suffering from diabetes the course of stroke is more severe, cerebral oedema appears more often and mortality is higher. In the present paper methods of rehabilitation and results achieved in a group of patients with stroke and a group of patients with stroke and diabetes mellitus are described, as well as effects of rehabilitation in both those groups. Fifty one (20%), out of 251 patients with cerebral stroke in the past who were rehabilitated in a Rehabilitation Department in 1997, had diabetes mellitus lasting, on average, 21 years. Individual rehabilitation programme for each patient was arranged collectively, taking into consideration restrictions necessary in the course of diabetes, including education of patients. Multidirectional assessment of initial condition and condition after termination of the rehabilitation was carried out taking into consideration the scale of lesions (the Brunnstrom stages), functional scales and the quality of life index (the Barthel index). More objective parameters, i.e. the index of symmetry of loading of lower extremities and walking speed, were also applied. All the patients with both stroke and diabetes mellitus completed the planned rehabilitation programme, although the initial condition of patients with concomitant diabetes was worse than that of patients with stroke only, as far as most of the applied parameters of assessment were concerned. Also improvement achieved in diabetic patients was not observed in each of the parameters examined and differed from that achieved in the group of patients with stroke alone. We found, that in-hospital rehabilitation of patients with stroke and concomitant diabetes mellitus (even long lasting) resulted in a measurable and significant improvement of their condition evaluated multidirectionally, and that diabetes mellitus coexisting with stroke is not a contraindication to in-hospital rehabilitation. In patients with concomitant diabetes mellitus significant disturbances of during the rehabilitation were not found course diabetes mellitus. However they all required meticulous care and monitoring of carbohydrate metabolism, and the average time of their hospitalisation was longer by about 3 days.     

Determinants of nerve conduction recovery after nerve injuries: Compression duration and nerve fiber types

Introduction: The aims of this study were to determine the influences of: (1) timing of nerve decompression; and (2) nerve fiber types on the patterns of nerve conduction studies (NCS) after nerve injury. Methods: Nerve conduction studies (NCS) were performed on 3 models of nerve injury: (1) crush injury due to transient nerve compression (crush group); (2) chronic constriction injury (CCI), or permanent compression (CCI group); and (3) CCI with removal of ligatures, or delayed nerve decompression (De‐CCI group). Results: There were distinct patterns of NCS recovery. The crush and De‐CCI groups achieved similar motor nerve recovery, better than that of the CCI group. In contrast, recovery of sensory nerves was limited in the CCI and De‐CCI groups and was lower than in the crush group. Conclusions: Immediate relief of compression resulted in the best recovery of motor and sensory nerve conduction. In contrast, delayed decompression restored only motor nerve conduction. Muscle Nerve 52 : 107–112, 2015     

200例2型糖尿病患者神经传导速度检测分析

目的:探讨2型糖尿病(DM)患者周围神经病变的客观神经电生理特点。方法:分别对200例DM患者,其中有周围神经损害临床表现组(DM-I)100例和无周围神经损害临床表现组(DM-Ⅱ)100例,与50例正常成人进行运动神经传导速度(MCV)、感觉神经传导速度(SCV)、复合肌肉动作电位(CMAP)、感觉神经动作电位(SNAP)进行测定。结果:两组患者所测的MCV、SCV、CMAP、SNAP与正常对照组比较有显著差异,而DM-I组与DM-II所测的MCV、SCW、CMAP、SNAP比较亦有显著差异,下肢神经的4个参数总异常率高于上肢。结论:(1)神经传导速度的检测有助于糖尿病周围神经病的早期诊断。(2)DM并发周围神经损害在临床症状出现之前已有神经传导速度的改变。(3)下肢神经的总异常率高于上肢。     

Abnormality of peripheral nerve conduction velocity associated with illness course, symptoms and fasting blood glucose in patients with type 2 diabetes mellitus

It has shown that abnormality of peripheral nerve conduction velocity during onset of diabetes mellitus is not related to age and sex, but to symptoms, illness course and level of fasting blood glucose.OBJECTIVE: To measure correlation of abnormality of peripheral nerve conduction velocity with various illness courses, symptoms and levels of fasting blood glucose of patients with type 2 diabetes mellitus.DESIGN: Case analysis.SETTING: Department of Neurology, Central People‘s Hospital of Huizhou.PARTICIPANTS: A total of 128 patients who were diagnosed as type 2 diabetes mellitus were selected from Central People‘s Hospital of Huizhou from September 2001 to October 2005. There were 75 males and 53 females aged 32-83 years and the illness course ranged from 1 month to 20 years.METHODS: All 128 patients with type 2 diabetes mellitus received neuro-electrophysiological study and their clinical data were retrospectively analyzed to measure peripheral nerve conduction velocity and fasting blood glucose so as to investigate the correlation of peripheral nerve conduction velocity with clinical symptoms,illness course and levels of fasting blood glucose.MAIN OUTCOME MEASURES: Correlation of peripheral nerve conduction velocity with clinical symptoms, illness course and levels of fasting blood glucose.RESULTS: All 128 patients with type 2 diabetes mellitus were involved in the final analysis. ① Among 128patients, 114 patients had abnormality of peripheral nerve conduction velocity; 110 patients had clinical symptoms, including 102 patients having abnormality of peripheral nerve conduction velocity; 18 patients did not have clinical symptoms, including 12 patients having abnormality of peripheral nerve conduction velocity.There were significant differences between them (x2=8.275, P=0.04). ② Among 128 patients, illness course of 75 patients was equal to or less than 5 years, including 27 patients having abnormality of peripheral nerve conduction velocity; illness course of 53 patients was more than 5 years, including 35 patients having abnormality of peripheral nerve conduction velocity. There were significant differences between them (x2=11.469,P =0.003). ③ Among 128 patients, levels of fasting blood glucose of 75 patients was equal to or lower than 11 mmol/L, including 41 patients having abnormality of peripheral nerve conduction velocity; levels of fasting blood glucose of 53 patients was higher than 11 mmol/L, including 38 patients having abnormality of peripheral nerve conduction velocity. There were significant differences between them (x2=4.023, P =0.134).CONCLUSION: ① Abnormality of peripheral nerve conduction velocity of patients with type 2 diabetes mellitus is related to illness courses and clinical symptoms. The longer the illness course is, the severer the abnormality of peripheral nerve conduction velocity is. Abnormality of peripheral nerve conduction velocity always occurs on patients who have clinical symptoms. ② Abnormality of peripheral nerve conduction velocity is not related to levels of fasting blood glucose.     

Remyelination and recovery of conduction in cat optic nerve after demyelination by pressure

Pressure has been applied to the optic nerve of cats sufficient to block conduction in the large (Y) nerve fibers. The pressure block produces a mixture of axotomy and demyelination. By means of implanted electrodes, recovery of conduction in these fibers was monitored. There is a short-term recovery starting about 2 weeks after block induction and finishing at about 4 weeks. A later recovery starts at about 6-7 weeks and finishes at about 10-11 weeks. The remyelination has been monitored in the electron microscope by measurement of the myelin thickness and axon diameter of the large fibers. The remyelination follows a time course similar to the late phase of conduction recovery. By reference to the work of others, we surmise that the early recovery of conduction is due to the reorganization of microtubules disorganized by the pressure.     

Peripheral and central conduction abnormalities in diabetes mellitus

OBJECTIVES: To investigate peripheral and central somatosensory conduction in patients with diabetes. METHODS: The authors recorded sensory nerve action potentials and 5-channel somatosensory evoked potentials (SEPs) with noncephalic reference after median nerve stimulation in 55 patients with diabetes and 41 age- and height-matched normal subjects. The authors determined onset or peak latencies of the Erb's potential (N9) and the spinal N13-P13 and the cortical N20-P20 components, and obtained the central conduction time (CCT) by onset-to-onset and peak-to-peak measurements. RESULTS: Both onset and peak latencies of all SEP components were prolonged in patients with diabetes. The mean onset CCT in the diabetic group was 6.3 +/- 0.5 msec (mean +/- SD)-significantly longer than that in the control group (6.1 +/- 0.2 msec)-whereas no significant difference was found in the peak CCT. The amplitudes of N9 and N13-P13 components (but not N20-P20) were significantly smaller in the diabetic group. The peripheral sensory conduction velocity was also decreased in the diabetic group, but there was no significant correlation between peripheral conduction slowing and the onset of CCT prolongation. CONCLUSIONS: Diabetes affects conductive function in the central as well as peripheral somatosensory pathways. The CCT abnormality does not coincide with lowering of the peripheral sensory conduction. The current results do not favor a hypothesis that a central-peripheral distal axonopathy plays an important role in development of diabetic polyneuropathy.     

Ultrasound therapy facilitates the recovery of acute pressure-induced conduction block of the median nerve in rabbits

Though the use of ultrasound for the treatment of carpal tunnel syndrome (CTS) or compression neuropathy has been described, its effect remains controversial. A test model of acute CTS was developed using rabbits. Acute median nerve compression was induced by the infusion of saline into the carpal tunnel under general anesthesia to elevate the intracarpal pressure. A reduction in the compound muscle action potential (CMAP) amplitude of the abductor pollicis was noted after intracarpal pressure increased. To investigate the efficacy of ultrasound in acute CTS, rabbits with acute median nerve compression were divided into 3 groups (10 each) and ultrasound was applied at different intensities to each group as follows: 1.5 W/cm(2) to group 1; 0.2 W/cm(2) to group 2; 0.0 W/cm(2) (sham) to group 3. A total of 10 treatment sessions were given over a period of 2 weeks. Following ultrasound application, the CMAP amplitudes showed significant improvement in group 1 compared to the other two groups (P < 0.05), indicating facilitated recovery from acute CTS in this pressure-induced median nerve compression rabbit model. The benefits of ultrasound application in a clinical setting must be verified by further clinical trials.     

Delayed auditory brainstem responses in diabetes mellitus

Diabetic patients have longer interpeak latencies in the brainstem auditory evoked responses than age-matched controls. The delay is not related to clinical hearing loss or blood glucose level at time of testing. Since waves I and II are normal in latency, the conduction velocity of the eighth nerve is not involved. The delay occurs between waves II and V, which would reflect altered transmission times in auditory brainstem and midbrain structures, and suggests the presence of a central neuropathy in patients with diabetes.     

Delayed somatosensory conduction in acute painful neuropathy of diabetes

We examined the peripheral–central sensory conduction by using somatosensory evoked potential (SEP) in a 48 year old diabetic patient with acute painful neuropathy. The sural, ulnar and median sensory nerve conduction and SEP elicited by wrist stimulation showed no abnormalities, nevertheless, the tibial nerve SEP revealed absent spinal N19 and a remarkable delay of the cortical arrival time. These findings suggest involvement of the dorsal roots or the dorsal column in the acute painful neuropathy of diabetes.     

Delayed post-traumatic bilateral abducens nerve palsy with complete recovery

Isolated bilateral abducens (sixth) nerve palsy is rare in the setting of trauma. To date, most cases have been reported in patients who sustain cranial fractures or have other acute intracranial pathologies, including acute hemorrhage. We describe the case of a 41-year-old man who presented with bilateral abducens nerve palsy in the setting of acute head trauma without evidence of cranial fractures or other acute intracranial pathology. Six months after the initial injury, he regained bilateral function of his abducens nerves with intact extraocular muscle movements. Full recovery is the natural history in the majority of traumatic abducens nerve palsies, and this is an important consideration when counseling patients with such injuries.     

Resistance to ischaemic conduction failure in chronic hypoxaemia and diabetes.

Median nerve function was studied in twelve diabetic subjects, six subjects with chronic hypoxaemia and ten control subjects. Resistance to ischaemic conduction failure (RICF), a characteristic electrophysiological feature of diabetic neuropathy, was assessed by measuring the decline in median nerve action potential amplitude at minute intervals for up to 20 minutes while the arm was rendered ischaemic. Initial nerve conduction velocity and action potential amplitude was similar in all three groups. Following the onset of ischaemia the time to a 50% reduction in action potential amplitude was prolonged in both diabetic subjects and hypoxaemic subjects compared with controls. After 20 minutes of ischaemia no control subject had persisting nerve function, while function remained in 5 (80%) of hypoxaemic subjects and 10 (83%) of diabetic subjects. The time to a 50% reduction in action potential amplitude during ischaemia correlated with the blood oxygen saturation among the hypoxic subjects and haemoglobin Alc among diabetic subjects. These results are consistent with the hypothesis that hypoxia has a role in the pathogenesis of resistance to ischaemic conduction failure in diabetes.