Objective:To explore the feasibility of shortening the time of long exercise test (LET) from 120 to 60 minutes by analyzing the positive rate within 60 minutes among periodic paralysis (PP) patients who were positive in 120-minute test.Methods:The data of patients undergoing 120-minute LET from January 2015 to October 2021 in Beijing Tiantan Hospital, Capital Medical University were retrospectively analyzed, with 30%, 33%, and 40% as diagnostic cut-off values, respectively. PP patients with positive results within 120 minutes after exercise were enrolled in the study. The positive rate within 30 minutes and 60 minutes after exercise was calculated. The change rates of compound muscle action potential (CMAP) amplitude and the sensitivity and specificity of LET at 30 minutes, 60 minutes, and 120 minutes after exercise were analyzed. The change rate of CMAP amplitude in PP patients who did not show positive results within 60 minutes was further calculated.Results:A total of 254 patients were examined, including 114 PP patients. With 30%, 33%, and 40% as diagnostic cut-off values, the results showed that there were 88, 88, and 82 positive PP patients, respectively. Under each diagnostic cut-off values, the age of positive PP patients was (32±10) years, with a male proportion of 98% (86/88), 98% (86/88), and 99% (81/82), respectively; the positive rate of PP patients within 30 minutes after exercise was 60% (53/88), 58% (51/88), and 41% (34/82), respectively; the positive rate of PP patients within 60 minutes after exercise was 91% (80/88), 86% (76/88), and 83% (68/82), respectively. At the cut-off values of 30%, 33% and 40%, the change rate of CMAP amplitude at 30 minutes [-36% (-49%, -23%), -36% (-49%, -23%), -37% (-51%, -24%)], 60 minutes [-51% (-66%, -40%), -51% (-66%, -40%), -53% (-66%, -42%)] and 120 minutes [-57% (-67%, -45%), -57% (-67%, -45%), -58% (-67%, -46%)] after exercise showed statistically significant difference among 3 time points ( H=57.764, 57.764, 59.616, respectively, all P<0.001); the further comparison between time points showed that there was statistically significant difference in the change rate of CMAP amplitude between 60 minutes ( Z=5.419, 5.419, 5.531, respectively, all P<0.001), 120 minutes ( Z=7.325, 7.325, 7.431, respectively, all P<0.001) and 30 minutes after exercise, but there was no statistically significant difference in the change rate of CMAP amplitude between 120 minutes and 60 minutes after exercise ( Z=1.906, 1.906, 1.899, respectively, all P>0.05); the sensitivity of LET for the diagnosis of PP at 60 minutes after exercise was 70.2% (80/114), 66.7% (76/114) and 59.6% (68/114), and the specificity of LET for the diagnosis of PP was 77.9% (109/140), 84.3% (118/140) and 91.4%(128/140), respectively. When 30%, 33% and 40% were used as the diagnostic cut-off values, and the change rate of CMAP amplitude at 60 minutes after exercise fell below these cut-off values but showed a decline of ≥20%, ≥22% and ≥24%, respectively, the detection time should be extended to 120 minutes. Conclusions:Whether using 30%, 33%, or 40% as diagnostic cut-off values, it is feasible to shorten the LET time from 120 minutes to 60 minutes. The 60-minute LET has good sensitivity and specificity for the diagnosis of PP. It is recommended to extend the detection time to 120 minutes for patients with a ≥20%, ≥22%, or ≥24% decline in CMAP amplitude at 60 minutes after exercise while falling short of corresponding diagnostic cut-off values when 30%, 33%, and 40% are used as diagnostic cut-off values. This method can not only improve the examination efficiency of LET, but also minimize the missed diagnosis as much as possible.

Objective:To explore the feasibility of shortening the time of long exercise test (LET) from 120 to 60 minutes by analyzing the positive rate within 60 minutes among periodic paralysis (PP) patients who were positive in 120-minute test.Methods:The data of patients undergoing 120-minute LET from January 2015 to October 2021 in Beijing Tiantan Hospital, Capital Medical University were retrospectively analyzed, with 30%, 33%, and 40% as diagnostic cut-off values, respectively. PP patients with positive results within 120 minutes after exercise were enrolled in the study. The positive rate within 30 minutes and 60 minutes after exercise was calculated. The change rates of compound muscle action potential (CMAP) amplitude and the sensitivity and specificity of LET at 30 minutes, 60 minutes, and 120 minutes after exercise were analyzed. The change rate of CMAP amplitude in PP patients who did not show positive results within 60 minutes was further calculated.Results:A total of 254 patients were examined, including 114 PP patients. With 30%, 33%, and 40% as diagnostic cut-off values, the results showed that there were 88, 88, and 82 positive PP patients, respectively. Under each diagnostic cut-off values, the age of positive PP patients was (32±10) years, with a male proportion of 98% (86/88), 98% (86/88), and 99% (81/82), respectively; the positive rate of PP patients within 30 minutes after exercise was 60% (53/88), 58% (51/88), and 41% (34/82), respectively; the positive rate of PP patients within 60 minutes after exercise was 91% (80/88), 86% (76/88), and 83% (68/82), respectively. At the cut-off values of 30%, 33% and 40%, the change rate of CMAP amplitude at 30 minutes [-36% (-49%, -23%), -36% (-49%, -23%), -37% (-51%, -24%)], 60 minutes [-51% (-66%, -40%), -51% (-66%, -40%), -53% (-66%, -42%)] and 120 minutes [-57% (-67%, -45%), -57% (-67%, -45%), -58% (-67%, -46%)] after exercise showed statistically significant difference among 3 time points ( H=57.764, 57.764, 59.616, respectively, all P<0.001); the further comparison between time points showed that there was statistically significant difference in the change rate of CMAP amplitude between 60 minutes ( Z=5.419, 5.419, 5.531, respectively, all P<0.001), 120 minutes ( Z=7.325, 7.325, 7.431, respectively, all P<0.001) and 30 minutes after exercise, but there was no statistically significant difference in the change rate of CMAP amplitude between 120 minutes and 60 minutes after exercise ( Z=1.906, 1.906, 1.899, respectively, all P>0.05); the sensitivity of LET for the diagnosis of PP at 60 minutes after exercise was 70.2% (80/114), 66.7% (76/114) and 59.6% (68/114), and the specificity of LET for the diagnosis of PP was 77.9% (109/140), 84.3% (118/140) and 91.4%(128/140), respectively. When 30%, 33% and 40% were used as the diagnostic cut-off values, and the change rate of CMAP amplitude at 60 minutes after exercise fell below these cut-off values but showed a decline of ≥20%, ≥22% and ≥24%, respectively, the detection time should be extended to 120 minutes. Conclusions:Whether using 30%, 33%, or 40% as diagnostic cut-off values, it is feasible to shorten the LET time from 120 minutes to 60 minutes. The 60-minute LET has good sensitivity and specificity for the diagnosis of PP. It is recommended to extend the detection time to 120 minutes for patients with a ≥20%, ≥22%, or ≥24% decline in CMAP amplitude at 60 minutes after exercise while falling short of corresponding diagnostic cut-off values when 30%, 33%, and 40% are used as diagnostic cut-off values. This method can not only improve the examination efficiency of LET, but also minimize the missed diagnosis as much as possible.

Objective:To explore the clinical and electrophysiological characteristics of peripheral neuropathy in prediabetic patients.Methods:Subjects aged 20-65 years with high-risk factors of impaired glycemia enrolled in Beijing Tiantan Hospital, Capital Medical University from 2019 to 2022 were recruited to conduct oral glucose tolerance test, after excluding other causes of neuropathy or radiculopathy. Patients with impaired fasting glucose or impaired glucose tolerance were defined by American Diabetes Association criteria. These patients were divided into clinical polyneuropathy (PN) and clinical non-PN groups, according to the 2010 Toronto consensus criteria and the presence of PN symptoms and signs or not. Nerve conduction studies (NCS), F wave, sympathetic skin response (SSR), R-R interval variation (RRIV) and current perception thresholds (CPT) were performed and the abnormal rate was compared between different electrodiagnostic methods and between clinical subgroups.Results:Among the 73 prediabetic patients ultimately enrolled, only 20 (27.4%) can be diagnosed as clinical PN according to the Toronto consensus criteria. The abnormal rate of CPT (68.5%, 50/73) was significantly higher than those of F wave (2.7%, 2/73), lower limb NCS (0, 0/73), upper limb NCS changes of carpal tunnel syndrome (26.0%, 19/73), SSR (6.8%, 5/73) and RRIV (5.5%, 4/73; McNemar test, all P<0.001). With sinusoid-waveform current stimuli at frequencies of 2 000 Hz, 250 Hz and 5 Hz, the CPT device was used to measure cutaneous sensory thresholds of large myelinated, small myelinated and small unmyelinated sensory fibers respectively. CPT revealed a 21.9% (16/73) abnormal rate of unmyelinated C fiber in the hands of prediabetic patients, significantly higher than that of large myelinated Aβ fibers [8.2% (6/73), χ2=5.352, P=0.021]. Both abnormal rates of small myelinated Aδ [42.5% (31/73)] and unmyelinated C fibers [39.7% (29/73)] in the feet of prediabetic patients were significantly higher than that of large myelinated Aβ fibers [11.0% (8/73), χ2=18.508, 15.965, both P<0.001]. Compared with the clinical non-PN group, the abnormal rates of CPT [90.0% (18/20) vs 60.4% (32/53), χ2=5.904, P=0.015] and SSR [20.0% (4/20) vs 1.9% (1/53), P=0.016) were significantly higher in the clinical PN group. Conclusions:Peripheral neuropathies in prediabetic patients are usually asymptomatic or subclinical, and predispose to affect unmyelinated and small myelinated sensory fibers. Selective electrodiagnostic measurements of small fibers help to detect prediabetic neuropathies in the earliest stages of the disease.

Objective:To determine whether there is a correlation between the cross-sectional area (CSA) and the parameters as measured on nerve conduction studies.Methods:Twenty-one patients with neuromuscular diseases in Beijing Tiantan Hospital from March 3, 2022 to May 4, 2023 underwent ultrasound measurement of the CSA of the median nerves and ulnar nerves at the wrist, elbow and the upper arm, followed by nerve conduction studies (NCS). A linear regression model was performed to compare NCS and CSA.Results:A total of 180 sets of motor nerve conduction velocity (MCV) and CSA at the different sites including 102 sets of median nerve and 78 sets of ulnar nerve, 220 sets of compound muscle action potential (CMAP) amplitude and CSA at the different sites including 104 sets of median nerve and 116 sets of ulnar nerve, 60 sets of sensory nerve conduction velocity (SCV) and CSA and sensory nerve action potential (SNAP) amplitude and CSA at the wrist including 32 sets of median nerve and 28 sets of ulnar nerve were recorded. The linear correlation between MCV and CSA was statistically significant both in median nerve ( r2=0.10,adjusted r2=0.09, P=0.001) and in ulnar nerve ( r2=0.18,adjusted r2=0.17, P<0.001).When CSA>10 mm 2, the linear correlation between CMAP amplitude and CSA was statistically significant both in median nerve ( r2=0.09,adjusted r2=0.08, P=0.024) and ulnar nerve ( r2=0.19,adjusted r2=0.17, P=0.004). The correlation between CMAP and CSA was not statistically significant when CSA≤10 mm 2. And the correlations between SCV and CSA and between SNAP and CSA were not statistically significant. Conclusions:CSA can better show the characteristics of changes in motor nerve conduction especially in motor conduction velocity. It is suggested that its application prospect in demyelinating peripheral neuropathy with motor nerve damage may be more extensive.

Objective:To analyze the clinical, electromyographic and tremor characteristics in tremor patients with neuronal intranuclear inclusion disease (NIID).Methods:From May 2018 to April 2023, 34 patients with NIID diagnosed in the Department of Neurology, Beijing Tiantan Hospital of Capital Medical University were retrospectively included. Sixteen patients with tremor of at least one limb and (or) head were in tremor group, and 18 patients without tremor were in control group. The clinical, electromyogram and tremor data of all participants were summarized, the clinical features and electromyogram differences of the 2 groups were compared, and the tremor characteristics of patients with NIID were analyzed.Results:The proportion of female patients in the tremor group was higher than that in the non tremor group (12/16 vs 7/18, P=0.045). The proportion of upper and lower limb peripheral nerve damage in the tremor group was lower than that in the non tremor group (2/16 vs 9/18, P=0.030), with statistical significance. There was no significant difference between the 2 groups in higher cortex and autonomic nervous dysfunction. The amplitude of composite muscle action potential and sensory nerve action potential in all patients was normal or slightly decreased; some patients experienced a decrease in motor and sensory fiber conduction velocity. The proportion of motor and sensory nerve conduction velocity slowing in the non tremor group was higher than that in the tremor group [motor nerve:41.7%(30/72) vs 17.2%(11/64), χ 2=9.64, P=0.002;sensory nerve:38.9% (35/90) vs 20.0%(16/80), χ 2=7.19, P=0.007]. The number of cases of postural tremors in different parts among the 16 patients was as follows: 13 in the upper limbs, 7 in the lower limbs, and 6 in the head; static tremor: 8 cases in the upper limbs, 3 cases in the lower limbs, and 5 cases in the head. At rest, the frequency of tremors in different parts of the body was as follows: upper limb (5.3±1.1) Hz, lower limb (4.2±0.4) Hz, and head (3.9±0.6) Hz. The difference in tremor frequency among the 3 parts was statistically significant ( F=3.92, P=0.047); Pairwise comparison showed that the frequency of head tremor was lower than that of upper limb tremor, with a statistically significant difference ( P=0.020). In a postural state, tremor frequency in different parts was as follows: upper limb (5.4±0.9) Hz, lower limb (5.0±0.7) Hz, head (3.9±0.7) Hz. There was a statistically significant difference in tremor frequency among the 3 parts ( F=6.65, P=0.005). Further pairwise comparison revealed statistically significant differences in tremor frequency between the patient′s head, upper and lower limbs ( P=0.001, P=0.022). Synchronous tremor rhythm was predominant, with occasional alternations or synchronous+alternations. There was no harmonic tremor spectrum was observed. Conclusions:NIID patients with tremors were more common in female patients.The degree of peripheral nerve damage was milder than those without tremors. The site and form of tremor were diverse, with a dominant frequency of 4-6 Hz, mainly synchronous rhythm, and no harmonic spectrum. Postural tremors were common in the limbs.

CADASIL (cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy) is a hereditary small vessel disease originated from adult onset, which is caused by the mutation of NOTCH3 gene located in the region of chromosome 19p13. Its clinical features include recurrent ischemic stroke, progressive cognitive impairment, migraine and mental disorders. Recent studies have shown that the mutations in the EGFr region of NOTCH3 gene are associated with the course, clinical manifestations and imaging features of CADASIL. This article reviews the research progress of the NOTCH3 gene EGFr region mutation genotype, clinical phenotype of CADASIL and their correlation, hoping to provide ideas for the early diagnosis and pathogenesis of CADASIL.

Objective:To investigate the electrophysiological features of patients with anti-neurofascin 155 (NF155) IgG4 antibodies positive chronic inflammatory demyelinating polyradiculoneuropathy (CIDP).Methods:The electrophysiological data of 6 anti-NF155 IgG4 antibodies positive CIDP patients in Beijing Tiantan Hospital, Capital Medical University from September 2018 to May 2021 were retrospectively analyzed. Parameters studies included standard motor and sensory nerve conduction studies, electromyography (EMG) and F waves studies. Correlation analysis was made to explore the relationships between clinical indicators and electrophysiological data.Results:There was statistically significant difference in the motor nerve conduction study on abnormal rate of tibial nerve (χ 2=11.08, P=0.011). Motor nerve conduction abnormalities were presented in a majority of patients with decreased motor conduction velocity (MCV) and prolonged distal motor latency (DML). There was no statistically significant difference in the overall abnormal rate between lower limbs and upper limbs (30/32, 93.8% vs 22/22, 100.0%; χ 2=1.43, P=0.508), sensory nerve conduction and motor nerve conduction (52/54, 96.3% vs 42/42, 100.0%; χ 2=1.59, P=0.503). There was statistically significant difference in the overall abnormal rate in median nerve, ulnar nerve and sural nerve (χ 2=14.96, P=0.001;χ 2=10.00, P=0.007; χ 2=9.95, P=0.008),and absent sensory nerve action potential was the most common abnormality in sensory nerve conduction abnormalities. The abnormal rate of EMG was 9/14, which was constituted by upper limbs (4/8) and lower limbs (5/6), and the spontaneous activity accompanied with prolonged duration and increased amplitude of motor unit action potential was common. Significant negative correlations were established between disease duration and compound muscle action potential (CMAP) amplitude and negative area of ulnar nerve ( r=-0.84, P=0.036; r =-0.76, P=0.011), and the correlations between age and MCV of median nerve and ulnar nerve were also found ( r=0.89, P=0.019; r=0.95, P=0.003). The DML of median nerve was negatively correlated with CMAP amplitude ( r=-0.63, P=0.049). Moreover, the correlation analysis revealed associations of the F wave latency with the DML, CMAP amplitude and MCV of tibial nerve ( r= 0.90, P=0.039; r=-0.96, P=0.012; r=-0.96, P=0.010). Conclusions:The motor nerve and sensory nerve, the myelin sheath and axon of peripheral nerves in anti-NF155 IgG4 CIDP patients were largely affected. The CMAP amplitude and negative area of ulnar nerve might be of certain clinical value in reflecting the disease duration.The younger the patients, the more severe the demyelination degree of the upper limbs. The F wave latency of tibial nerve not only reflected the abnormal proximal conduction, but also the distal damage degree of myelin sheath and axon.

Objective:To report the clinical, pathological, electrophysiological and genic characteristics of a patient with familial amyloidosis Finnish type.Methods:The clinical characteristic of a 60-year-old female who admitted to Beijing Tiantan Hospital, Capital Medical University in June 2020 was analyzed. Meanwhile, the patient underwent electrophysiological examination, biopsy of labial gland, rectum and skin and gene sequencing analysis.Results:The patient presented left facial paralysis at the age of 50, right facial paralysis and thickening of lips at the age of 55, dysarthria and dysphagia at the age of 56. Physical examination of the patient showed signs of cranial nerves involvement and skin thinning and smoothness. Slit lamp showed corneal lattice dystrophy. Electrophysiological findings of the patient suggested bilateral carpal tunnel syndrome. Latencies were prolonged in bilateral visual evoked potential P100. The deep sensory conduction pathways in bilateral C 7 to biparietal and T 12 to biparietal cortex were abnormal. Pathology of the three biopsies of the patient showed the presence of amyloid deposition in the basement membrane around the glands. The heterozygous mutation of c.654 G>T in exon 4 of gelsolin (GSN) gene in the patient resulted in Asp187 Tyr mutation (p.D187Y). Conclusions:The patient with familial amyloidosis Finnish type was characterized by slowly progressive multiple group cranial neuropathy accompanied by corneal lattice dystrophy and skin changes. Optic nerve and spinal cord posterior funiculus sensory conduction pathway and D187Y mutation of GSN gene were involved.

Objective To investigate the diagnostic value of spontaneous activities in genioglossus of amyotrophic lateral sclerosis (ALS).Methods A retrospective analysis of 79 patients diagnosed with ALS from January 2014 to December 2015 in Beijing Tiantan Hospital Affiliated to Capital Medical University was made.The patients were divided into two groups according to the clinical examination:with (44 patients) or without bulbar symptoms (35 patients).The course of disease,spontaneous potentials and ALS-Functional Rating Scale (ALS-FRS) scores were discussed,together with the association between semi-quantitative evaluation of spontaneous potential of the genioglossus and ALS-FRS score.Results In ALS patients,the overall positive rate of glossal spontaneous potentials was 69.6％ (55/79),among which the positive rate was 82.9％ (29/35) in patients with bulbar symptoms and 59.1％ (26/44) in patients without bulbar symptoms,with statistically significant differences between the two groups (x2=5.206,P＜0.05).While the positive rate in sternocleidomastoid was only 13.9％ (11/79),and there was no statistically significant difference between patients with or without bulbar symptoms.Semi-quantitative evaluation of fibrillation potentials in genioglossus muscle was correlated with ALS-FRS score (r=-0.258,P＜0.05).Conclusion Compared with sternocleidomastoid muscle,genioglossus muscle has a higher positive rate of spontaneous potentials and a higher diagnostic value in patients with subclinical bulbar symptoms.

Objective To optimize the method to elicit the facial nerve F wave and to establish its reference values and its related parameters, in order to provide an electrophysiological basis for facial nerve assessment in patients with hemifacial spasm (HFS). Methods Thirty-six healthy volunteers and 22 patients with HFS underwent this project. Compound muscle action potentials (CAMP, or M waves) and F waves were elicited by stimulating the marginal mandibular branch of the facial nerve and recorded with needle electrodes placed in the mentalis muscle. The association between F parameters and Cohen Grading of the HFS patients were analyzed. Results There were no significant differences in F parameters between men and women or between the two sides in control subjects. Minimal latency of F wave (Fmin) and mean latency of F wave (Fmean) had positive correlations with head circumference (Fmin r=0.449, P=0.013; Fmean r=0.391, P=0.033), but had no correlations with age nor height. Patients with HFS had prolonged duration of F wave (Fdura) in spasm side, compared with normal side (13.1 ms vs. 9.5 ms, P<0.01) and healthy subjects (13.1 ms vs. 9.7 ms, P<0.001), and increased ratio of F-wave amplitude and M-wave amplitude (F/M) in spasm side, compared with normal side (6.9% vs. 3.8%, P<0.001) and healthy subjects (6.9% vs. 3.7%, P<0.001). F/M exhibited a positive correlation with Cohen Grading (r=0.538, P=0.001). Conclusion A clear facial nerve F wave can be achieved by stimulating the marginal mandibular branch of the facial nerve, which provides an objective basis for evaluation of the facial nerve function in HFS patients with increased F/M and prolonged Fdura.