Differentiated pattern of complement system activation between MOG-IgG-associated disease and AQP4-IgG-positive neuromyelitis optica spectrum disorder.

Background: Myelin oligodendrocyte glycoprotein antibody (MOG) immunoglobulin G (IgG)-associated disease (MOGAD) has clinical and pathophysiological features that are similar to but distinct from those of aquaporin-4 antibody (AQP4-IgG)-positive neuromyelitis optica spectrum disorders (AQP4-NMOSD). MOG-IgG and AQP4-IgG, mostly of the IgG1 subtype, can both activate the complement system. Therefore, we investigated whether the levels of serum complement components, regulators, and activation products differ between MOGAD and AQP4-NMOSD, and if complement analytes can be utilized to differentiate between these diseases. Methods: The sera of patients with MOGAD (from during an attack and remission; N=19 and N=9, respectively) and AQP4-NMOSD (N=35 and N=17), and healthy controls (N=38) were analyzed for C1q-binding circulating immune complex (CIC-C1q), C1 inhibitor (C1-INH), factor H (FH), C3, iC3b, and soluble terminal complement complex (sC5b-9). Results: In attack samples, the levels of C1-INH, FH, and iC3b were higher in the MOGAD group than in the NMOSD group (all, p<0.001), while the level of sC5b-9 was increased only in the NMOSD group. In MOGAD, there were no differences in the concentrations of complement analytes based on disease status. However, within AQP4-NMOSD, remission samples indicated a higher C1-INH level than attack samples (p=0.003). Notably, AQP4-NMOSD patients on medications during attack showed lower levels of iC3b (p<0.001) and higher levels of C3 (p=0.008), C1-INH (p=0.004), and sC5b-9 (p<0.001) compared to those not on medication. Among patients not on medication at the time of attack sampling, serum MOG-IgG cell-based assay (CBA) score had a positive correlation with iC3b and C1-INH levels (rho=0.764 and p=0.010, and rho=0.629 and p=0.049, respectively), and AQP4-IgG CBA score had a positive correlation with C1-INH level (rho=0.836, p=0.003). Conclusions: This study indicates a higher prominence of complement pathway activation and subsequent C3 degradation in MOGAD compared to AQP4-NMOSD. On the other hand, the production of terminal complement complexes (TCC) was found to be more substantial in AQP4-NMOSD than in MOGAD. These findings suggest a strong regulation of the complement system, implying its potential involvement in the pathogenesis of MOGAD through mechanisms that extend beyond TCC formation.

Sympathetic dysfunction as an early indicator of autonomic involvement in Parkinson's disease.

PURPOSE: The specific characteristics of autonomic involvement in patients with early Parkinson's disease (PD) are unclear. This study aimed to evaluate the characteristics of autonomic dysfunction in drug-naïve patients with early-stage PD without orthostatic hypotension (OH) by analyzing Valsalva maneuver (VM) parameters. METHODS: We retrospectively analyzed drug-naïve patients without orthostatic hypotension (n = 61) and controls (n = 20). The patients were subcategorized into early PD (n = 35) and mid-PD (n = 26) groups on the basis of the Hoehn and Yahr staging. VM parameters, including changes in systolic blood pressure at late phase 2 (∆SBPVM2), ∆HRVM3, Valsalva ratio (VR), pressure recovery time, adrenergic baroreflex sensitivity, and vagal baroreflex sensitivity, were assessed. RESULTS: In the early PD group, ∆SBPVM2, a marker of sympathetic function, was significantly lower compared with that in controls (risk ratio = 0.95, P = 0.027). Receiver operating characteristic (ROC) curve analysis showed an optimal cut-off value of -10 mmHg for ∆SBPVM2 [P = 0.002, area under the curve (AUC): 0.737]. VR exhibited an inverse relationship with Unified Parkinson's Disease Rating Scale Part 3 scores in the multivariable regression analysis (VR: P = 0.038, ß = -28.61), whereas age showed a positive relationship (age: P = 0.027, ß = 0.35). CONCLUSION: The ∆BPVM2 parameter of the VM may help detect autonomic nervous system involvement in early-PD without OH. Our results suggest that sympathetic dysfunction is an early manifestation of autonomic dysfunction in patients with PD.

Serial Nerve Conduction Studies in Guillain-Barré Syndrome: Its Usefulness and Precise Timing.

PURPOSE: Nerve conduction study (NCS) is essential for subclassifying Guillain-Barré syndrome (GBS). It is well known that the GBS subclassification can change through serial NCSs. However, the usefulness of serial NCSs is debatable, especially in patients with early stage GBS. METHODS: Follow-up NCS data within 3 weeks (early followed NCS, EFN) and within 3 to 10 weeks (late-followed NCS, LFN) were collected from 60 patients with GBS who underwent their first NCS (FN) within 10 days after symptom onset. Each NCS was classified into five subtypes (normal, demyelinating, axonal, inexcitable, and equivocal), according to Hadden's and Rajabally's criteria. We analyzed the frequency of significant changes in classification (SCCs) comprising electrodiagnostic aggravation and subtype shifts between demyelinating and axonal types according to follow-up timing. RESULTS: Between FN and EFN, 33.3% of patients with Hadden's criteria and 18.3% with Rajabally's criteria showed SCCs. Between FN and LFN, 23.3% of patients with Hadden's criteria and 21.7% with Rajabally's criteria showed SCCs, of which 71.4% (Hadden's criteria) and 46.2% (Rajabally's criteria) already showed SCCs from the EFN. The conditions of delayed SCCs between EFN and LFN were very early FN, mild symptoms at the FN, or persistent electrophysiological deterioration 3 weeks after symptom onset. CONCLUSIONS: A substantial proportion of patients with GBS showed significant changes in neurophysiological classification at the early stage. Serial NCS may be helpful for precise neurophysiological classification. This study suggests that follow-up NCSs should be performed within 3 weeks of symptom onset in patients with GBS in whom FN was performed within 10 days of symptom onset.

Prognostic factors of first-onset optic neuritis based on diagnostic criteria and antibody status: a multicentre analysis of 427 eyes.

BACKGROUND: Optic neuritis (ON) prognosis is influenced by various factors including attack severity, underlying aetiologies, treatments and consequences of previous episodes. This study, conducted on a large cohort of first ON episodes, aimed to identify unique prognostic factors for each ON subtype, while excluding any potential influence from pre-existing sequelae. METHODS: Patients experiencing their first ON episodes, with complete aquaporin-4 (AQP4) and myelin oligodendrocyte glycoprotein (MOG) antibody testing, and clinical data for applying multiple sclerosis (MS) diagnostic criteria, were enrolled. 427 eyes from 355 patients from 10 hospitals were categorised into four subgroups: neuromyelitis optica with AQP4 IgG (NMOSD-ON), MOG antibody-associated disease (MOGAD-ON), ON in MS (MS-ON) or idiopathic ON (ION). Prognostic factors linked to complete recovery (regaining 20/20 visual acuity (VA)) or moderate recovery (regaining 20/40 VA) were assessed through multivariable Cox regression analysis. RESULTS: VA at nadir emerged as a robust prognostic factor for both complete and moderate recovery, spanning all ON subtypes. Early intravenous methylprednisolone (IVMP) was associated with enhanced complete recovery in NMOSD-ON and MOGAD-ON, but not in MS-ON or ION. Interestingly, in NMOSD-ON, even a slight IVMP delay in IVMP by >3 days had a significant negative impact, whereas a moderate delay up to 7-9 days was permissible in MOGAD-ON. Female sex predicted poor recovery in MOGAD-ON, while older age hindered moderate recovery in NMOSD-ON and ION. CONCLUSION: This comprehensive multicentre analysis on first-onset ON unveils subtype-specific prognostic factors. These insights will assist tailored treatment strategies and patient counselling for ON.

Dynamic suprahyoid muscle ultrasound in assessing oropharyngeal dysphagia in neurological disorders.

BACKGROUND: Appropriate evaluation and management of dysphagia are essential in neurological disorders. However, there is currently a lack of a simple yet reliable method for dysphagia evaluation. AIM: This study aimed to investigate the usefulness of new dynamic M-mode ultrasonography (US) parameters of suprahyoid muscle (SHM) to evaluate dysphagia. DESIGN: Prospective observational, cross-sectional study. SETTING: Inpatient setting at neurology department of tertiary medical center. POPULATION: A total of 89 patients with dysphagia and 175 healthy volunteers were enrolled in the study. Patients were subdivided into mild and severe dysphagia groups depending on the need for dietary changes and disease classification, which included amyotrophic lateral sclerosis, peripheral neuromuscular diseases, and stroke. METHODS: Dynamic M-mode US was performed during swallowing to obtain the SHM thickness (the baseline thickness of the SHM), SHM displacement (peak-to-peak amplitude of SHM movement), SHM difference (SHM displacement - SHM thickness), SHM ratio (SHM displacement/SHM thickness), peak-to-peak time, and total duration. A videofluoroscopic swallowing study (VFSS) was performed. RESULTS: Significant differences were found in SHM displacement and SHM difference according to dysphagia severity (P<0.001). The SHM ratio, total duration (P<0.001), and peak-to-peak time (P=0.001) differed significantly according to the patients' underlying diseases. The pharyngeal delay time and penetration-aspiration scale from the VFSS demonstrated significant negative correlations with SHM displacement and difference (P<0.001). By combining SHM difference and total duration, patients with dysphagia could be distinguished from healthy controls, with the highest negative predictive value of 95.6%. CONCLUSIONS: Dynamic M-mode US of the SHM provided added value in evaluating the severity of dysphagia and differentiating swallowing mechanics of dysphagia related to underlying neurological disorders. CLINICAL REHABILITATION IMPACT: Dynamic M-mode US of the SHM can serve as a supportive tool for rapid screening and repetitive follow-up of patients with dysphagia, which would contribute to dysphagia rehabilitation in patients with various neurological disorders.

The semicircular canal function is preserved with little impact on falls in patients with mild Parkinson's disease.

INTRODUCTION: Postural instability is a cardinal symptom of Parkinson's disease (PD), which suggests the vestibular system may be affected in PD. This study aimed to determine whether vestibular dysfunction is associated with the risk of falls in PD. METHODS: We prospectively recruited patients with de-novo PD at a tertiary medical center between December 2019 and March 2023. During initial assessment, each patient was queried about falls within the preceding year. All patients underwent evaluation of video head-impulse tests (video-HITs), motion analysis, mini-mental state examination (MMSE), and Montreal Cognitive Assessment (MOCA). We determined whether head impulse gain of the vestibulo-ocular reflex (VOR) was associated with clinical severity of PD or risk of falls. RESULTS: Overall, 133 patients (mean age ± SD = 68 ± 10, 59 men) were recruited. The median Movement Disorder Society-Unified Parkinson's Disease Rating Scale motor part (MDS-UPDRS-III) was 23 (interquartile range = 16-31), and 81 patients (61 %) scored 2 or less on the Hoehn and Yahr scale. Fallers were older (p = 0.001), had longer disease duration (p = 0.001), slower gait velocity (p = 0.009), higher MDS-UPDRS-III (p < 0.001) and H&Y scale (p < 0.001), lower MMSE (p = 0.018) and MOCA scores (p = 0.001) than non-fallers. Multiple logistic regression showed that MDS-UPDRS-III had a positive association with falling (p = 0.004). Falling was not associated with VOR gain (p = 0.405). The VOR gain for each semicircular canal showed no correlation with the MDS-UPDRS-III or disease duration. CONCLUSIONS: The semicircular canal function, as determined by video-HITs, is relatively spared and has little effect on the risk of falls in patients with mild-to-moderate PD.

Effects of pupil size in video head-impulse tests.

The results of video head impulse tests (video-HITs) may be confounded by data artifacts of various origins, including pupil size and eyelid obstruction of the pupil. This study aimed to determine the effect of these factors on the results of video-HITs. We simulated ptosis by adopting pharmacological dilatation of the pupil in 21 healthy participants (11 women; age 24-58 years). Each participant underwent video-HITs before and after pupillary dilatation using 0.5% tropicamide. We assessed the changes in the vestibulo-ocular reflex (VOR) gain, corrective saccade amplitude, and frequency of eyelid flicks. After pupillary dilatation, the VOR gain decreased for both right (RAC; 1.12 [Formula: see text] 0.12 vs. 1.01 [Formula: see text] 0.16, p = 0.011) and left anterior canals (LACs; 1.15 [Formula: see text] 0.13 vs. 0.96 [Formula: see text] 0.14, p < 0.001), and right posterior canal (RPC, 1.10 [Formula: see text] 0.13 vs. 0.98 [Formula: see text] 0.09, p = 0.001). The corrective saccade amplitudes also decreased significantly for all four vertical canals. The frequency of eyelid flicks, however, did not change. The changes of VOR gain were positively correlated with the lid excursion in RPC (r = 0.629, p = 0.002) and LPC (r = 0.549, p = 0.010). Our study indicates that eyelid position and pupil size should be considered when interpreting the results of video-HITs, especially for the vertical canals. Pupils should be shrunk in a very well-lit room, and artifacts should be prevented by taping or lifting the eyelids as required during video-HITs.

Scale for Ocular Motor Disorders in Ataxia (SODA) in Patients with Multiple System Atrophy.

A clinical scale fully dedicated to evaluating ocular motor abnormalities is required for now. We investigated the utility of a recently developed Scale for Ocular motor Disorders in Ataxia (SODA) in patients with multiple system atrophy (MSA). We prospectively assessed SODA in consecutive patients with MSA between August 2021 and August 2023 at the Korea University Medical Center. The results of the clinical exam-based SODA were compared with those measured using video-oculography (VOG-guided SODA). We also compared the findings with other established clinical scales targeting patients with MSA, including the Unified Multiple System Atrophy Rating Scale (UMSARS) I-II, Movement Disorder Society-Unified Parkinson's Disease Rating Scale motor part (UPDRS-III), Scale for Assessment of Rating of Ataxia (SARA), Composite Autonomic Symptom Score-31 (COMPASS-31), and Composite Autonomic Severity Score (CASS). Twenty patients were enrolled in our study (17 with cerebellar-type MSA and three with Parkinson-type MSA). Scores ranged from 1 to 14 (median [interquartile range (IQR)] = 8 [5-10]). Among the subscales, saccades had a median score of 2.5 (IQR = 1-3), followed by ocular pursuit (1 [0-1]), nystagmus (1 [0-2]), saccadic intrusions (1 [0-1]), vestibulo-ocular reflex (VOR) (0.5 [0-1]), ocular alignment (0 [0-1]), and VOR cancellation (1 [0-1]). The clinical-exam-based SODA (p = 0.020) and VOG-guided SODA (p = 0.034) positively correlated with disease duration. No correlation was found between clinical exam-based SODA and other scales. Skew deviation, gaze-evoked nystagmus, VOR cancellation, and smooth pursuit had the highest precision among the items. Ocular misalignment and spontaneous and positional nystagmus were frequently false positive and were poorly detected with clinical exam-based SODA. Six patients with repeated evaluation exhibited higher scores, along with deterioration documented on other clinical scales. The SODA can reliably predict neurodegeneration as an additional clinical surrogate in MSA.

Serum neurofilament and glial fibrillary acidic protein in idiopathic and seropositive transverse myelitis.

BACKGROUND: Serum levels of neurofilament light chain (NfL) and glial fibrillary acidic protein (GFAP) reflect the disease activity and disability in central nervous system (CNS) demyelinating diseases. However, the clinical significance of NfL and GFAP in idiopathic transverse myelitis (iTM), an inflammatory spinal cord disease with unknown underlying causes, remains unclear. This study aimed to investigate NfL and GFAP levels in iTM and their association with the clinical parameters compared with those in TM with disease-specific antibodies such as anti-aquaporin 4 or myelin oligodendrocyte glycoprotein antibodies (sTM). METHODS: We collected serum and clinical data of 365 patients with CNS inflammatory diseases from 12 hospitals. The serum NfL and GFAP levels were measured in patients with iTM (n = 37) and sTM (n = 39) using ultrasensitive single-molecule array assays. Regression analysis was performed to investigate the associations between serum levels of NfL and GFAP and the clinical parameters such as higher EDSS scores (EDSS ≥ 4.0). RESULTS: Mean NfL levels were not significantly different between iTM (50.29 pg/ml) and sTM (63.18 pg/ml) (p = 0.824). GFAP levels were significantly lower in iTM (112.34 pg/ml) than in sTM (3814.20 pg/ml) (p = 0.006). NfL levels correlated with expanded disability status scale (EDSS) scores in sTM (p = 0.001) but not in iTM (p = 0.824). Disease duration also correlated with higher EDSS scores in sTM (p = 0.017). CONCLUSION: NfL levels and disease duration correlated with EDSS scores in sTM, and GFAP levels could be a promising biomarker to differentiate iTM from sTM.

Clinical Features and Neurotologic Findings in Patients With Acute Unilateral Peripheral Vestibulopathy Associated With Antiganglioside Antibody.

BACKGROUND AND OBJECTIVES: Anecdotal studies have reported the presence of antiganglioside antibodies in acute unilateral peripheral vestibulopathy (AUPV). This study aimed to determine the prevalence, clinical characteristics, and neurotologic findings of AUPV associated with antiganglioside antibodies. METHODS: Serum antigangliosides were measured in consecutive patients with AUPV according to the Bárány Society criteria during the acute and recovery phases in a referral-based university hospital in South Korea from September 2019 to January 2023. Clinical characteristics and neurotologic findings were compared between those with and without antiganglioside antibodies. The results of video-oculography, video head impulse and bithermal caloric tests, and other neurotologic evaluations including ocular and cervical vestibular-evoked myogenic potentials and subjective visual vertical were compared between the 2. MRIs dedicated to the inner ear were also conducted when considered necessary. RESULTS: One hundred five patients (mean age ± SD = 60 ± 13 years, 57 male) were included for analyses. During the acute phase, 12 patients (12/105, 11%) were tested positive for serum antiganglioside antibodies, including anti-GQ1b immunoglobulin (Ig) G (n = 5) or IgM (n = 4), anti-GM1 IgM (n = 3), and anti-GD1a IgG (n = 1, including 1 patient with a positive anti-GQ1b antibody). Patients with antiganglioside antibodies showed lesser intensity of spontaneous nystagmus (median [interquartile range] = 1.8 [1.2-2.1] vs 3.4 [1.5-9.5], p = 0.003) and a lesser degree of canal paresis (30 [17-47] vs 58 [34-79], p = 0.028) and gain asymmetry of the vestibulo-ocular reflex for the horizontal semicircular canal during head impulse tests (0.07 [-0.04 to 0.61] vs 0.36 [0.18-0.47], p = 0.032) than those without antibodies. Negative conversion of antibodies and vestibular recovery were observed in most patients (6/8, 75%). Among 30 patients with AUPV with 4-hour delayed 3D fluid-attenuated inversion recovery dedicated to the inner ear, gadolinium enhancement was observed in 18 (18/30, 60%), either in the vestibule (n = 9), semicircular canal (n = 6), or vestibular nerve (n = 5). The positivity rates based on specific antibodies could not be determined due to limited sample sizes. DISCUSSION: The association between antiganglioside antibodies and AUPV suggests an immune-mediated mechanism in acute vestibular failure and extends the clinical spectrum of antiganglioside antibody syndrome.

Surface Electromyography-Driven Parameters for Representing Muscle Mass and Strength.

The need for developing a simple and effective assessment tool for muscle mass has been increasing in a rapidly aging society. This study aimed to evaluate the feasibility of the surface electromyography (sEMG) parameters for estimating muscle mass. Overall, 212 healthy volunteers participated in this study. Maximal voluntary contraction (MVC) strength and root mean square (RMS) values of motor unit potentials from surface electrodes on each muscle (biceps brachii, triceps brachii, biceps femoris, rectus femoris) during isometric exercises of elbow flexion (EF), elbow extension (EE), knee flexion (KF), knee extension (KE) were acquired. New variables (MeanRMS, MaxRMS, and RatioRMS) were calculated from RMS values according to each exercise. Bioimpedance analysis (BIA) was performed to determine the segmental lean mass (SLM), segmental fat mass (SFM), and appendicular skeletal muscle mass (ASM). Muscle thicknesses were measured using ultrasonography (US). sEMG parameters showed positive correlations with MVC strength, SLM, ASM, and muscle thickness measured by US, but showed negative correlations with SFM. An equation was developed for ASM: ASM = -26.04 + 20.345 × Height + 0.178 × weight - 2.065 × (1, if female; 0, if male) + 0.327 × RatioRMS(KF) + 0.965 × MeanRMS(EE) (SEE = 1.167, adjusted R2 = 0.934). sEMG parameters in controlled conditions may represent overall muscle strength and muscle mass in healthy individuals.

Augmented ocular vestibular-evoked myogenic potentials in postural orthostatic tachycardia syndrome.

PURPOSE: To delineate the association between otolith function and changes in mean orthostatic blood pressure (BP) and heart rate (HR) in patients with postural orthostatic tachycardia syndrome (POTS). METHODS: Forty-nine patients with POTS were prospectively recruited. We analyzed the results of ocular vestibular-evoked myogenic potentials (oVEMPs) and cervical vestibular-evoked myogenic potentials (cVEMPs), as well as head-up tilt table tests using a Finometer. The oVEMP and cVEMP responses were obtained using tapping stimuli and 110 dB tone-burst sounds, respectively. We measured maximal changes in 5-s averaged systolic BP (SBP), diastolic BP (DBP), and heart rate (HR) within 15 s and during 10 min after tilting. We compared the results with those of 20 age- and sex-matched healthy participants. RESULTS: The n1-p1 amplitude of oVEMPs was larger in patients with POTS than in healthy participants (p = 0.001), whereas the n1 latency (p = 0.280) and interaural difference (p = 0.199) did not differ between the two. The n1-p1 amplitude was a positive predictor for POTS (odds ratio 1.07, 95% confidence interval 1.01-1.13, p = 0.025). Body weight (p = 0.007) and n1-p1 amplitude of oVEMP (p = 0.019) were positive predictors for ΔSBP15s in POTS, whereas aging was a negative predictor (p = 0.005). These findings were not observed in healthy participants. CONCLUSIONS: Augmented utricular inputs may be associated with a relative predominance of sympathetic over vagal control of BP and HR, especially for an early response during orthostasis in patients with POTS. Overt sympathoexcitation due to exaggerated utricular input and lack of readaptation may be associated with the pathomechanism of POTS.

Analyses of Head-Impulse Tests in Patients With Posterior Circulation Stroke and Vestibular Neuritis.

BACKGROUND AND OBJECTIVES: The interpretation of video head-impulse tests (video-HITs) can often be complicated, limiting their clinical utility in acute vestibular syndrome. We aimed to determine video-HIT findings in patients with posterior circulation strokes (PCSs) and vestibular neuritis (VN). METHODS: We retrospectively analyzed the results of video-HITs in 59 patients with PCS. Irrespective of the actual lesion revealed later on MRIs, ipsilateral and contralateral sides were assigned according to the direction of slow phase of spontaneous nystagmus (SN). Then, the patterns of video-HIT findings were classified according to the vestibulo-ocular reflex (VOR) gain for the horizontal canals; (1) ipsilaterally positive, (2) contralaterally positive, (3) bilaterally normal, and (4) bilaterally positive. The abnormal responses were further defined into (5) wrong-way saccades, (6) perverted, and (7) early acceleration followed by premature deceleration. We also analyzed the asymmetry of the corrective saccadic amplitude between the sides, calculated from the sum of cumulative saccadic amplitudes on both sides. The results were compared with video-HIT results from 71 patients with VN. RESULTS: Video-HITs were normal in 32 (54%), ipsilaterally positive in 11 (19%), bilaterally positive in 10 (17%), and contralaterally positive in 6 (10%) patients with PCS. Wrong-way saccades were more frequently observed in VN than in PCS (31/71 [44%] vs 5/59 [8%], p < 0.001). Saccadic amplitude asymmetry was greater in VN than in PCS (median 100% [interquartile range 82-144, 95% CI 109-160] vs 0% [-29 to 34, -10 to 22, p < 0.001]). When differentiating VN from PCS, the sensitivity was 81.7%, and specificity was 91.5% at the cutoff value of 71% for saccadic amplitude asymmetry with an area under the curve (AUC) of 0.91 (95% CI 0.86-0.97). The AUC for saccadic amplitude asymmetry was larger than that for the ipsilateral VOR gain (p = 0.041) and other parameters. DISCUSSION: Patients with PCS may show various head-impulse responses that deviate from the findings expected in VN, which include normal, contralaterally positive, and negative saccadic amplitude asymmetry (i.e., greater cumulative saccadic amplitude contralaterally). A thorough analysis of corrective saccades in video-HITs can improve the differentiation of PCS from VN even before MRIs.

Clinical application of functional near-infrared spectroscopy for burn assessment.

Significance: Early assessment of local tissue oxygen saturation is essential for clinicians to determine the burn wound severity. Background: We assessed the burn extent and depth in the skin of the extremities using a custom-built 36-channel functional near-infrared spectroscopy system in patients with burns. Methods: A total of nine patients with burns were analyzed in this study. All second-degree burns were categorized as superficial, intermediate, and deep burns; non-burned skin on the burned side; and healthy skin on the contralateral non-burned side. Hemodynamic tissue signals from functional near-infrared spectroscopy attached to the burn site were measured during fNIRS using a blood pressure cuff. A nerve conduction study was conducted to check for nerve damage. Results: All second-degree burns were categorized into superficial, intermediate, and deep burns; non-burned skin on the burned side and healthy skin on the contralateral non-burned side showed a significant difference distinguishable using functional near-infrared spectroscopy. Hemodynamic measurements using functional near-infrared spectroscopy were more consistent with the diagnosis of burns 1 week later than that of the degree of burns diagnosed visually at the time of admission. Conclusion: Functional near-infrared spectroscopy may help with the early judgment of burn extent and depth by reflecting differences in the oxygen saturation levels in the skin.

Use of Valsalva Maneuver to Detect Late-Onset Delayed Orthostatic Hypotension.

BACKGROUND: Standard autonomic testing includes a 10-minute head-up tilt table test to detect orthostatic hypotension. Although this test can detect delayed orthostatic hypotension (dOH) between 3 and 10 minutes of standing, it cannot detect late-onset dOH after 10 minutes of standing. METHODS: To determine whether Valsalva maneuver responses can identify patients who would require prolonged head-up tilt table test to diagnose late-onset dOH; patients with immediate orthostatic hypotension (onset <3 minutes; n=176), early-onset dOH (onset between 3 and 10 minutes; n=68), and late-onset dOH (onset >10 minutes; n=32) were retrospectively compared with controls (n=114) with normal head-up tilt table test and composite autonomic scoring scale score of 0. RESULTS: Changes in baseline systolic blood pressure at late phase 2 (∆SBPVM2), heart rate difference between baseline and phase 3 (∆HRVM3), and Valsalva ratio were lower and pressure recovery time (PRT) at phase 4 was longer in late-onset dOH patients than in controls. Differences in PRT and ∆HRVM3 remained significant after correcting for age. A PRT ≥2.14 s and ∆HRVM3 ≤15 bpm distinguished late-onset dOH from age- and sex-matched controls. Patients with longer PRT (relative risk ratio, 2.189 [1.579-3.036]) and lower ∆HRVM3 (relative risk ratio, 0.897 [0.847-0.951]) were more likely to have late-onset dOH. Patients with longer PRT (relative risk ratio, 1.075 [1.012-1.133]) were more likely to have early-onset than late-onset dOH. CONCLUSIONS: Long PRT and short ∆HRVM3 can help to identify patients who require prolonged head-up tilt table test to diagnose late-onset dOH.

Usefulness of muscle ultrasound in appendicular skeletal muscle mass estimation for sarcopenia assessment.

The measurement of skeletal muscle mass is essential for the diagnosis of sarcopenia. Muscle ultrasonography has emerged as a useful tool for evaluating sarcopenia because it can be used to assess muscle quality and quantity. This study investigated whether muscle ultrasonography is effective for estimating appendicular skeletal muscle mass (ASM) and screening for sarcopenia. This study prospectively enrolled 212 healthy volunteers aged 40-80 years. ASM was measured using the bioelectrical impedance analysis. Muscle thickness (MT) and echo-intensity (EI) were measured in four muscles (biceps brachii, BB; triceps brachii, TB; rectus femoris, RF; biceps femoris, BF) on the dominant hand. A hold-out cross-validation method was used to develop and validate the ASM prediction equation. In the model development group, the ASM prediction equations were deduced as follows: estimated ASM for men (kg) = 0.167 × weight (kg) + 0.228 × height (cm) + 0.143 × MT of BF (mm)- 0.822 × EI to MT ratio of BB- 28.187 (R2 = 0.830) and estimated ASM for women (kg) = 0.115 × weight + 0.215 × height (cm) + 0.139 × MT of RF-0.638 × EI to MT ratio of BB- 23.502 (R2 = 0.859). In the cross-validation group, the estimated ASM did not significantly differ from the measured ASM in both men (p = 0.775; intraclass correlation coefficient [ICC] = 0.948) and women (p = 0.516; ICC = 0.973). In addition, multiple logistic regression analysis revealed that the ratios of EI to MT in the BF and RF muscles in men and MT in the BB muscle in women could be valuable parameters for sarcopenia screening. Therefore, our study suggests that muscle ultrasound could be an effective tool for estimating ASM and screening sarcopenia.