The difference in nerve ultrasound and motor nerve conduction studies between autoimmune nodopathy and chronic inflammatory demyelinating polyneuropathy.

INTRODUCTION/AIMS: Nerve enlargement has been described in autoimmune nodopathy and chronic inflammatory demyelinating polyneuropathy (CIDP). However, comparisons of the distribution of enlargement between autoimmune nodopathy and CIDP have not been well characterized. To fill this gap, we explored differences in the ultrasonographic and electrophysiological features between autoimmune nodopathy and CIDP. METHODS: Between March 2015 and June 2023, patients fulfilling diagnostic criteria for CIDP were enrolled; among them, those with positive antibodies against nodal-paranodal cell-adhesion molecules were distinguished as autoimmune nodopathy. Nerve ultrasound and nerve conduction studies (NCS) were performed. RESULTS: Overall, 114 CIDP patients and 13 patients with autoimmune nodopathy were recruited. Cross-sectional areas (CSA) at all sites were larger in patients with CIDP and autoimmune nodopathy than in healthy controls. CSAs at the roots and trunks of the brachial plexus were significantly larger in patients with anti-neurofascin-155 (NF155), anti-contactin-1 (CNTN1), and anti-contactin-associated protein 1 (CASPR1) antibodies than in CIDP patients. The patients with anti-NF186 antibody did not have enlargement in the brachial plexus. NCS showed more frequent probable conduction block at Erb's point in autoimmune nodopathy than in CIDP (61.9% vs. 36.6% for median nerve, 52.4% vs. 39.5% for ulnar nerve). Markedly prolonged distal motor latencies were also present in autoimmune nodopathy. DISCUSSION: Patients with autoimmune nodopathies had distinct distributions of peripheral nerve enlargement revealed by ultrasound, as well as distinct NCS patterns, which were different from CIDP. This suggests the potential utility of nerve ultrasound and NCS to supplement clinical characteristics for distinguishing nodopathies from CIDP.

Characteristics of after-discharges following compound muscle action potential or F-wave in primary peripheral nerve hyperexcitability syndrome.

INTRODUCTION/AIMS: F-wave testing frequently reveals after-discharges of varied morphologies in patients with primary peripheral nerve hyperexcitability syndrome (PNHS), although reports are scant. This study aimed to explore the morphological characteristics of the after-discharges during F-wave tests in PNHS, and to assess the association between after-discharges and the disease classification. METHODS: We conducted a retrospective analysis of patients diagnosed with PNHS between 2014 and 2022. The morphological characteristic and duration of after-discharges during F-wave tests were analyzed. After-discharges in the Morvan syndrome group were compared with those in non-Morvan group, and between groups with positive or negative voltage-gated potassium channel (VGKC) complex antibodies. RESULTS: Twenty-nine patients were included in the study, of which 25 exhibited after-discharges. All after-discharges in Morvan patients occurred following compound muscle action potential (CMAP). In non-Morvan patients, after-discharges occurred following F-wave (32%) and CMAP (47%). The durations of after-discharges following CMAP were significantly prolonged in Morvan (54.2 ± 18.8 ms) compared to non-Morvan patients (34.5 ± 15.0 ms). The majority of antibody-positive patients (18/20) exhibited after-discharges following CMAP, whereas 67% of antibody-negative patients (6/9) showed after-discharges following F-wave. DISCUSSION: The varying presentations of after-discharges, including their location (after CMAP or F-wave) and the duration of after-discharge can assist in clinically classifying PNHS.

Treatment of primary progressive aphasia by repetitive transcranial magnetic stimulation: a randomized, double-blind, placebo-controlled study.

To evaluate the efficacy of high-frequency repetitive transcranial magnetic stimulation (rTMS) in patients with primary progressive aphasia (PPA). In this randomized, double-blind trial in a single center, patients who were diagnosed with PPA were randomly assigned to receive either real rTMS or sham rTMS treatment. High-frequency rTMS was delivered to the dorsolateral prefrontal cortex (DLPFC). The primary outcome was the change in Boston Naming Test (BNT) score at each follow-up compared to the baseline. The secondary outcomes included change in CAL (Communicative Activity Log) and WAB (Western Aphasia Battery) compared to baseline and neuropsychological assessments. Forty patients (16 with nonfluent, 12 with semantic and 12 with logopenic variant PPA) were enrolled and randomly assigned to the rTMS or sham rTMS group, with 20 patients in each group. Thirty-five patients (87.5%) completed a 6-month follow-up. Compared to the sham rTMS group, the BNT improvement and WAB improvement in the real rTMS group were significantly higher. These significant improvements could be observed throughout the entire 6-month follow-up. At 1 month and 3 months after treatment, CAL improvements of real rTMS were significantly higher than sham rTMS. The improvements in BNT, CAL and WAB did not significantly differ among PPA variants. No significant improvement in neuropsychological assessments was observed. High-frequency rTMS delivered to DLPFC improved language functions in patients with different PPA variants. The efficacy was still observed after 6 months of treatment. Trial registration: NCT04431401 ( https://clinicaltrials.gov/ct2/show/NCT04431401 ).

Nerve ultrasound may help predicting response to immune treatment in chronic inflammatory demyelinating polyradiculoneuropathy.

BACKGROUNDS: Nerve ultrasound has been proven to be an accurate tool in diagnosing chronic inflammatory demyelinating polyradiculoneuropathy (CIDP). However, its value in guiding treatment has not been well evaluated. The aim of this study was to explore whether nerve ultrasound and its changing trend could predict the response to immune treatment in CIDP. METHODS: Eighty-nine therapy-naive CIDP patients were recruited prospectively and treated with steroids and/or intravenous immunoglobulin (IVIG). Ultrasonographic and electrophysiological studies were performed on the median and ulnar nerves before treatment in all patients and followed up in 45 patients. The cross-sectional area (CSA) was measured at ten sites on both the median and ulnar nerves. RESULTS: The response rate to steroids (95%) was significantly higher than that to IVIG (70%) (P = 0.001) in patients with normal or moderately enlarged CSA, while there was no significant difference in the response rate between steroid therapy (84%) and IVIG (75%) (P = 0.653) in patients with markedly enlarged CSA. CSAs decreased in 15 patients during follow-up, most of whom had good IVIG and steroid responses (83%) and no need for immune suppressant treatment (82%). CONCLUSIONS: Nerve ultrasonography could help guide treatment strategies in patients with CIDP. Patients with normal or moderately enlarged CSA may respond better to steroids than to IVIG. The decrease in CSA after treatment may also indicate better prognosis.

Nerve ultrasound studies in POEMS syndrome.

INTRODUCTION: The aim of our study was to assess the ultrasonographic features of peripheral nerves in patients with POEMS (polyneuropathy, organomegaly, endocrinopathy, M protein, and skin changes) syndrome. METHOD: 34 POEMS syndrome patients and 26 healthy control (HC) participants were recruited prospectively. Cross-sectional area (CSA) was measured in nerves of limbs, trunks of brachial plexus, and cervical nerve roots RESULTS: The CSAs were mildly enlarged at the arm segment of median nerve, elbow segment of ulnar nerve and upper trunk, moderately enlarged at the forearm segment of both median and ulnar nerve, upper trunk of brachial plexus, and C6, C7 cervical nerve roots, and markedly enlarged at the arm segment of ulnar nerve, middle and lower trunk of brachial plexus, as well as C5 cervical root. DISCUSSION: The CSAs of upper limb nerves were larger in POEMS syndrome patients than in HCs, and the enlargements were most prominent proximally.

Sensitivity and specificity of single and combined clouds analyses compared with quantitative motor unit potential analysis.

INTRODUCTION: Turns-amplitude, number of small segments (NSS)-activity, and envelope-activity clouds are three methods of electromyography (EMG) interference pattern analysis. Our objective was to evaluate the sensitivity and specificity of each individual cloud analysis and combined clouds analysis to compare with that of quantitative motor unit potential (QMUP) analysis. METHODS: A total of 379 muscles from 100 patients were analyzed by both QMUP and clouds analyses. Calculation of sensitivity and specificity was based on the clinical diagnosis as the "gold standard." RESULTS: For discrimination of abnormal vs normal and neuropathic vs non-neuropathic, combined clouds analysis had greater sensitivity than QMUP analysis and any single cloud analysis, but there were no differences in specificity. For discrimination of myopathic vs non-myopathic, combined clouds analysis and single cloud analysis had greater sensitivity than QMUP analysis, but there were no differences in specificity. DISCUSSION: Combined clouds analysis was superior to QMUP and each single cloud analysis for distinguishing normal, myopathic, and neuropathic muscles.

Cross-sectional area reference values for sonography of nerves in the upper extremities.

INTRODUCTION: Detailed morphological features of the peripheral nerves could improve the diagnostic sensitivity in some polyneuropathies. In this study we aimed to establish multiple-site, cross-sectional area (CSA) reference values for peripheral nerves of upper extremities in a healthy Chinese population. METHODS: One hundred eleven healthy subjects, 15 to 70 years of age, were prospectively recruited. CSA at predetermined sites of the median, ulnar, radial nerves, and brachial plexus was measured bilaterally. Ten consecutive sites were studied along the median/ulnar nerves. RESULTS: The CSA at ten sites of the median nerve ranged from 5.59 ± 0.89 to 8.43 ± 1.30 mm2 , and for the ulnar nerve from 2.94 ± 0.57 to 5.63 ± 1.08 mm2 . Both age and gender correlated with nerve CSA at most sites. DISCUSSION: CSA was not uniform along the length of the median and ulnar nerves. The multiple-site reference values could be helpful for investigating polyneuropathies in the Asian population.

Serial nerve ultrasound and motor nerve conduction studies in chronic inflammatory demyelinating polyradiculoneuropathy.

INTRODUCTION: The objective of this study was to evaluate the correlation between cross-sectional area (CSA) and nerve conduction studies (NCS) in chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) and to determine how CSA changes over time after standard treatment. METHODS: Fifty-four patients with CIDP were recruited prospectively, and 21 patients were followed for more than 6 months. Ultrasonography and motor NCS were performed in the median and ulnar nerves. RESULTS: No or weak correlation was observed between the maximum CSA and motor conduction velocity. There were segmental nerve enlargements at 61% of sites with conduction block or temporal dispersion. Among 19 patients with clinical improvement after immunotherapy, CSA decreased to normal in 5, increased in 10, and were unchanged in 4. DISCUSSION: Different patterns of CSA and motor NCS changes after immune treatment may indicate different CIDP pathologic mechanisms. Exploration of these pathologic mechanisms could guide treatment choices in the future. Muscle Nerve, 2019.

Excessive daytime sleepiness in Chinese patients with sporadic amyotrophic lateral sclerosis and its association with cognitive and behavioural impairments.

OBJECTIVE: To examine the frequency and clinical features of excessive daytime sleepiness (EDS) and its association with cognitive and behavioural impairments in patients with amyotrophic lateral sclerosis (ALS). METHODS: We conducted a cross-sectional investigation to explore the frequency and clinical features of EDS in a group of 121 Chinese patients with ALS compared with 121 age-matched and sex-matched healthy subjects. EDS was diagnosed using the Epworth Sleepiness Scale (ESS). Other characteristics of patients with ALS including sleep quality, REM sleep behaviour disorder (RBD), restless legs syndrome (RLS), cognition, behaviour, depression and anxiety were also evaluated. RESULTS: EDS was significantly more frequent in patients with ALS than in controls (26.4% vs 8.3%; p<0.05). Patients with ALS with EDS scored lower scores on the revised ALS Functional Rating Scale (ALSFRS-R), Mini-Mental State Examination (MMSE), Montreal Cognitive Assessment (MoCA) and MMSE and MoCA delayed memory subitems and higher on the Frontal Behavioural Inventory (FBI) than patients with ALS without EDS. ESS scores correlated with global ALSFRS-R, FBI, MMSE and MoCA scores and MMSE and MoCA delayed memory scores. RLS and global ALSFRS-R scores were independently associated with EDS in patients with ALS. CONCLUSIONS: We identified a high frequency of EDS symptoms in Chinese patients with ALS, and these patients might have more serious physical, cognitive and frontal behaviour impairment. Patients with ALS might improve quality of life from the timely recognition and optimised management of EDS symptoms. Our results further suggest that ALS is a heterogeneous disease that might exhibit abnormal sleep-wake patterns.

Single-fiber EMG with concentric electrodes in lambert-eaton myasthenia.

INTRODUCTION: We analyzed jitter recordings made with concentric needle electrode (CNE) single-fiber electromyography (SFEMG) in Lambert-Eaton myasthenia (LEM). METHODS: Fifteen subjects diagnosed with LEM were studied using CNE-SFEMG in the extensor digitorum (ED) and tibialis anterior (TA) muscles. CNE-SFEMG in the ED and TA was also used to evaluate 12 and 10 healthy controls (HCs), respectively. RESULTS: Ten men and 5 women were diagnosed with LEM based on an increase of 100% in compound muscle action potential amplitude during 50 Hz repetitive nerve stimulation. All patients exhibited markedly greater jitter in the ED (88.8 ± 23.2 µs) and TA (92.2 ± 30.2 µs) than HCs (28.3 ± 3.4 µs and 30.9 ± 5.1 µs, respectively). CONCLUSIONS: CNE-SFEMG is sensitive for discovering abnormalities in neuromuscular transmission in LEM. Muscle Nerve 56: 253-257, 2017.

Synthesis and characterization of microencapsulated paraffin with melamine-urea-formaldehyde shell modified with lignin.

The study aims to fabricate MUF/paraffin microcapsules with lignin nanoparticles (LNPs)/ melamine-urea-formaldehyde (MUF) resin as hybrid shell material with different LNPs addition were synthesized in oil-in-water emulsion stabilized synergistically by styrene/maleic anhydride (SMA) and LNPs. The morphological characterization of LNPs was observed by transmission electron microscopy (TEM). The particle size of LNPs, the mean particle size and ξ potentials of SMA/LNPs mixture at pH =4.5 were investigated by zeta potential measurement. Field emission scanning electron microscopy (FE-SEM), Fourier-transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), thermogravimetric analyzer (TGA), and differential scanning calorimetry (DSC) were characterized the morphologies, crystallography, chemical component, thermal stability and phase change properties of MUF/paraffin microcapsules with different LNPs addition. The results showed that MUF/paraffin microcapsules were spherical. The LNPs did not influence the chemical structure or crystal type of MUF/paraffin microcapsules. When the LNPs addition was 0.15 g, the melting enthalpy and crystallization enthalpy is respectively 130.03 and 121.92 J/g and the encapsulation efficiency of MicroC-15 is 61.04 %.

Effects of Processing Conditions on the Properties of Monoammonium Phosphate Microcapsules with Melamine-Formaldehyde Resin Shell.

To develop monoammonium phosphate (MAP) as a novel acid source for durable intumescent fire retardants (IFR), MAP microcapsules (MCMAPs) containing MAP as the internal core and melamine-formaldehyde (MF) as the external shell were prepared by in situ polymerization in this study. The influences of synthesis conditions (including reaction temperature, polymerization time, and reaction pH value) on the properties of obtained MCMAPs (MAP content, yield, morphologies, and thermal properties) were then investigated systematically. The morphologies, chemical structures, and thermal properties were characterized by optical microscopy, scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), Fourier transform infrared (FTIR) spectroscopy, and thermogravimetry analyzer (TGA). The results show that MAP was well encapsulated by MF resin. No microcapsules are obtained at <55 °C or with polymerization times <1 h. Optimal preparation conditions of reaction temperature, polymerization time, and reaction pH value are 75 °C, 3 h, and 5.5, respectively. Those results provide process reference and theoretical basis for preparing MCMAPs and could promote the application of MAP microcapsules in wood flame-retardant materials.

Uncovering the true features of dystrophin gene rearrangement and improving the molecular diagnosis of Duchenne and Becker muscular dystrophies.

Duchenne and Becker muscular dystrophies (DMD/BMD) are caused by complex mutations in the dystrophin gene (DMD). Currently, there is no integrative method for the precise detection of all potential DMD variants, a gap which we aimed to address using long-read sequencing. The captured long-read sequencing panel developed in this study was applied to 129 subjects, including 11 who had previously unsolved cases. The results showed that this method accurately detected DMD mutations, ranging from single-nucleotide variations to structural variations. Furthermore, our findings revealed that continuous exon duplication/deletion in the DMD/BMD cohort may be attributed to complex segmental rearrangements and that noncontiguous duplication/deletion is generally attributed to intragenic inversion or interchromosome translocation. Mutations in the deep introns were confirmed to produce a pseudoexon. Moreover, variations in female carriers were precisely identified. The integrated and precise DMD gene screening method proposed in this study could improve the molecular diagnosis of DMD/BMD.

Nerve Ultrasound Performances in Differentiating POEMS Syndrome from CIDP.

Chronic inflammatory demyelinating polyneuropathy (CIDP) and polyneuropathy, organomegaly, endocrinopathy, M-protein, and skin changes (POEMS) syndrome are both acquired demyelinating polyneuropathies. We aim to explore the different features of ultrasonographic changes between CIDP and POEMS syndrome. Nerve ultrasonographic studies were performed in 120 patients with CIDP and 34 patients with POEMS syndrome. Cross-sectional areas (CSAs) were measured on the bilateral median nerve, ulnar nerve, and brachial plexus. Nerve conduction studies were performed on median and ulnar nerves to detect motor conduction blocks (CBs). CSAs at all sites were larger in patients with CIDP and POEMS syndrome than in healthy controls. Maximal CSA (median (min to max)) was 14 (6-194) mm2 for median nerve, 9 (4-92) mm2 for ulnar nerve, and 14 (7-199) mm2 for brachial plexus in CIDP and 11 (8-16) mm2 for median nerve, 8.5 (6-13) mm2 for ulnar nerve, and 14 (10-20) mm2 for brachial plexus in POEMS syndrome. The ratio of maximum/minimum CSA of the median nerve was significantly larger in CIDP (2.8 ± 2.8) than in POEMS syndrome (1.7 ± 0.3). CBs or probable CBs were detected in 60 out of 120 CIDP patients but in none of the POEMS syndromes. For distinguishing CIDP and POEMS syndrome, a two-step protocol using CB and maximum/minimum CSA of the median nerve yields a sensitivity of 93% and a specificity of 79%. In conclusion, compared with CIDP, nerve CSA enlargement was more homogeneous along the same nerve in individual POEMS patients, as well as among different POEMS patients. The addition of nerve ultrasound to nerve conduction studies significantly improves the differential diagnosis between the two diseases.

Reference values for lower limb nerve ultrasound and its diagnostic sensitivity.

We aimed to establish the cross-sectional area (CSA) reference values for peripheral nerves of lower extremities in a healthy Chinese population, and to determine their diagnostic values for chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) and Charcot-Marie-Tooth disease type1A (CMT1A). One hundred eleven healthy subjects, 15-70 years of age, as well as 104 CIDP patients and 26 CMT1A patients were recruited. CSA at predetermined sites of the tibial, fibular, sciatic and sural nerves was measured. The CSA of the tibial nerve ranged from 10.2 ± 1.9 to 20.7 ± 3.6 mm2, and for fibular nerve from 8.4 ± 1.8 to 9.5 ± 1.9 mm2. 86% CIDP patients had upper limb nerve enlargement, while only 67% had lower limb nerve enlargement. In CIDP patients with normal upper limb ultrasound, 56% (5/9) would have lower limb nerve enlargement. All CMT1A patients had both upper and lower limb nerve enlargement. Addition of lower limb nerve ultrasound showed no added value in diagnosis of CMT1A, but could be supplementary for CIDP when upper limb ultrasound is normal.

Corticospinal Tract Impairment of Patients With Parkinson's Disease: Triple Stimulation Technique Findings.

BACKGROUND: Corticospinal tract impairment is no longer an absolute exclusion in the updated Movement Disorder Society Parkinson's disease criteria. Triple stimulation technique (TST) is an accurate method to quantitatively assess the integrity and impairment of corticospinal pathway in a variety of neurological diseases. This study aims to evaluate the corticospinal tract impairment in Parkinson's disease (PD) patients using TST. METHODS: Ten PD patients, 19 multiple-system atrophy parkinsonian variant (MSA-P) patients, and 12 healthy controls (HC) were sequentially recruited in this study. Information of age, disease duration, pyramidal signs, and Hoehn and Yahr (H&Y) stage was obtained from all patients. The TST was assessed at right abductor digiti minimi for HCs and both sides for patients. The Chi-square test was used for categorical variables, and variance analysis was performed for continuous variables in comparing the difference among PD, MSA-P, and HC, plus the post hoc tests for pairwise comparisons. RESULTS: All subjects were age and gender matched. There was no significant difference in disease duration (p = 0.855), H-Y stage (p = 0.067), and the percentage of pyramidal signs present (p = 0.581) between MSA-P and PD patients. The mean TST ratio was 55.5 ± 32.2%, 81.7 ± 19.8%, and 96.8 ± 3.0% for PD, MSA-P, and HCs, correspondingly. PD patients had a significant lower TST amplitude ratio than MSA-P and HCs. The TST ratio of MSA-P was lower than HCs, but there was no significant difference (p = 0.160). Additionally, it was significantly higher in percentage of abnormal TST ratio between PD patients and MSA-P (p = 0.010). CONCLUSION: Corticospinal tract impairment is not a rare manifestation in PD and can be quantitatively evaluated with TST. The result needs to be verified in amplified sample.

A prospective study on split-hand index as a biomarker for the diagnosis of amyotrophic lateral sclerosis.

OBJECTIVE: To determine the practical diagnostic utility of split-hand index (SI) values calculated from F-wave persistence (SIFP) and the F/M amplitude ratio (SIF/M) for differentiating patients with amyotrophic lateral sclerosis (ALS) from other conditions. Methods: This prospective study recruited consecutive patients from Peking Union Medical College Hospital, China, between June 2019 and December 2019. Patients 18-80 years old who had clinical neuromuscular symptoms affecting the upper limbs and required electrophysiological examinations to aid diagnosis were eligible. Compound muscle action potentials (CMAPs) and F-waves recorded from the abductor pollicis brevis (APB), first dorsal interosseous muscle (FDI), and abductor digiti minimi (ADM) were examined. SIFP and SIF/M were calculated as: SI = (APB × FDI)/ADM. The sensitivity and specificity of SIFP and SIF/M in differentiating ALS from non-ALS conditions were derived using receiver operating characteristic (ROC) curves. Results: A total of 309 participants, comprising 91 (29.4%) with ALS and 218 (70.6%) with other neuromuscular disorders, were enrolled after 54 were excluded. SIFP was significantly reduced and SIF/M increased in the ALS group compared with the non-ALS group (p < 0.001). By ROC curve analysis, an SIFP cutoff of 73.3 showed 85.7% sensitivity and 80.7% specificity for differentiating ALS from non-ALS. SIF/M and SICMAP showed lower sensitivity (67% and 75.8%, respectively, p < 0.001) than SIFP for ALS diagnosis. SIFP and SIF/M combined did not outperform SIFP alone. Conclusion: SIFP could be a sensitive, noninvasive neurophysiological diagnostic marker for ALS patients with affected upper limbs. In particular, an SIFP value of 73.3 might be the optimal cutoff for diagnosing ALS.

Vagus Nerve Ultrasound in Chronic Inflammatory Demyelinating Polyradiculoneuropathy and Charcot-Marie-Tooth Disease Type 1A.

BACKGROUND AND PURPOSE: Both clinical autonomic dysfunction and involvement of autonomic nerves have been reported in a range of peripheral nerve disorders. We employed nerve ultrasound to assess the size of the vagus nerve in a serial study of patients with chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) and Charcot-Marie-Tooth type 1B (CMT1B) as compared to healthy controls (HCs). We correlated these findings with involvement of the median and ulnar nerves. METHODS: Forty-three patients with CIDP, 8 with CMT1A, and 105 HC were prospectively recruited. The cross-sectional areas (CSAs) of the vagus, median, and ulnar nerves were measured bilaterally. The alteration of CSA of those nerves was followed longitudinally in CIDP. RESULTS: The median (range) CSA of the vagus nerve was 2 (1-28) mm2 in CIDP, 3 (2-6) mm2 in CMT1A, and 1 (1-2) mm2 in HC. The vagus nerve CSA was positively correlated with the maximum CSA of median/ulnar nerve in CIDP and CMT1A. The alteration in vagus nerve CSA was positively correlated with the alteration in mean median/ulnar nerve CSA in CIDP during follow-up. CONCLUSIONS: The vagus nerve was involved to a similar extent as the median and ulnar nerves in CIDP and CMT1A, although no symptoms or signs of vagus nerve involvement were found. Further study should be performed to explore the clinical relevance of vagus nerve enlargement in these disorders.

Split-Hand Syndrome in Amyotrophic Lateral Sclerosis: Differences in Dysfunction of the FDI and ADM Spinal Motoneurons.

The F-wave test allows for the non-invasive assessment of spinal motoneuron excitability. We investigated the difference in spinal motoneuron dysfunction between the first dorsal interosseous (FDI) and abductor digit minimi (ADM) muscles by investigating F-waves and to assess the contribution of spinal mechanisms to split-hand syndrome in patients with amyotrophic lateral sclerosis (ALS). Sixty-five consecutive ALS patients and twenty age- and gender-matched healthy controls (HCs) were enrolled. Motor nerve conduction studies and F-waves were performed bilaterally on median and ulnar nerves in all subjects. HCs revealed prominently longer F-wave latencies, lower chronodispersion, mean F-wave amplitude, and mean and maximal F/M amplitude ratio (P < 0.001) in the FDI compared to the ADM. However, no significant differences in almost all F-wave parameters between the FDI and ADM were observed in ALS patients with affected hands except the minimal and mean F-wave latency. These data suggest that excitability is greatly changed in the spinal motoneurons innervating the FDI. Furthermore, the mean F-wave amplitude (r = 0.454, P = 0.002) of the FDI was significantly correlated with the FDI/ADM CMAP amplitude ratio in ALS patients with affected hands but not of the ADM. Our findings suggested that the dysfunction of spinal motoneurons between the FDI and ADM was different in ALS, and spinal motoneuron dysfunction was associated with development of the split-hand phenomenon.

Split-hand index in amyotrophic lateral sclerosis: an F-wave study.

Objective: Split-hand sign is a useful clinical and electrophysiological feature in the diagnosis of amyotrophic lateral sclerosis (ALS). We proposed a novel split-hand index (SI) using F-wave persistence (FP) and assessed its diagnostic utility in ALS. Methods: Eighty-three consecutive ALS patients were recruited, and 50 healthy, age-, and height-matched volunteers were used as a control group. Compound muscle action potentials (CMAP) and FP were recorded from the abductor pollicis brevis (APB), first dorsal interosseous (FDI), and the abductor digiti minimi (ADM) muscles. The SI derived from FP was calculated using the following formula: SIFP = (FPAPB ×FPFDI)/FPADM. The sensitivity and specificity of SIFP and SICMAP in differentiating ALS from healthy controls (HCs) were derived from receiver-operating characteristic (ROC) curve analysis. Results: Both SIFP and SICMAP were significantly reduced in ALS patients. The ROC curve analysis indicated that both SIFP and SICMAP reliably differentiated ALS from HCs [0.92 (95% CI: 0.88-0.95); 0.86 (95% CI: 0.82-0.91)], but SIFP showed better diagnostic accuracy than SICMAP (p = 0.04), with a high sensitivity (81.2%) and specificity (97%). In subgroup analyses, SIFP appeared to be a better variable than SICMAP for differentiation of ALS patients with normal CMAP from HCs, with an area under the curve of 0.87 (95% CI: 0.80-0.93), sensitivity of 69.4%, and specificity of 94%. Conclusion: The SIFP reliably distinguished ALS patients from HCs and may be more sensitive for determining the split-hand pattern of ALS than SICMAP, particularly in the early stage of the disease.