Quantification of vestibular perception during caloric test

Perioperative vestibular assessment and testing

Frontoparietal function and underlying structure reflect capacity for motor skill acquisition during healthy aging

BackgroundOne candidate biomarker for Alzheimer's Disease (AD) is the hyperexcitability of the hippocampus in presymptomatic stages or Mild Cognitive Impairment that transforms into hypoactivation with disease progression. A potential tool to measure this neural shift is repetition suppression, defined as the neural tuning over repeated information during memory formation. Yet, to establish such a neural biomarker, it is important to characterize the aging effects on repetition suppression in the hippocampus. By leveraging high temporal and spatial properties of magnetoencephalography (MEG), we examined distinct neural activation profiles in the hippocampus associated with repetition suppression in healthy young versus older adults, aiming to identify a promising avenue for a neural biomarker for AD.MethodsWe collected MEG recordings from 53 participants, 27 healthy young (F=20, Age=18‐34) and 26 older adults (F=17, Age=60+), while they viewed series of scenes, where some images repeated after variable (2 to 8 item) lags. We aligned participant‐specific MEG data with their structural images and localized hippocampal signals through beamformer analyses. Repetition suppression was computed as the oscillatory difference between the novel and the repeated presentation of the images. In each group, we characterized the clusters of neural synchronies with time‐frequency analyses. We compared the probability of significant synchrony differences between the two groups against a null distribution in a permutation test.ResultsHealthy older adults exhibited significant clusters of hippocampal alpha (8‐12Hz) and beta (13‐30Hz) desynchronizations for the repeated images in comparison to the novel (p <0.001), indicating more neural activity. The desynchronization of the hippocampus for the repeated images was not as pronounced in healthy young adults. In fact, permutation testing revealed that the extent of beta desynchronization for the repeated presentation was significantly greater in the hippocampus of healthy older adults than young (p <0.05).ConclusionNeural tuning of the hippocampus during memory formation, namely repetition suppression, changes with age; expressed as greater neural activation in healthy older adults. Characterizing the aging effects on repetition suppression may offer a promising avenue for examination of hippocampal hyperexcitability as a potential biomarker for AD.

With great interest, we read the letter to the editor of Dr Bulent Mamikoglu in response to our paper “The Differences in Caloric Test and vHIT Results Between Menière’s Disease and Vestibular Migraine: A Systematic Review and Meta-Analysis.” The author of this letter seems to conclude that VM is a disorder of central network modulation that is susceptible to peripheral perturbations, including pressure-coupled perilymph changes and otolith dysregulation, in subsets of patients. This model aligns with (1) CSF–perilymph literature, (2) pressure-linked oval-window mechanics, (3) BPPV comorbidity, and (4) IIH-spectrum associations. The assertion that disorders unrelated to vestibular migraine (VM) or migraine in general provide evidence for vestibular migraine being a peripheral disorder is not supported by current clinical or pathophysiological data. Multiple lines of evidence indicate that vestibular migraine is primarily a disorder of central origin, involving sensitization and altered processing within central vestibular pathways. Functional neuroimaging studies have suggested abnormal connectivity and activity in brain regions responsible for multisensory vestibular integration and sensorimotor control in patients with vestibular migraine, supporting a central mechanism rather than a peripheral vestibulopathy.1,2 Clinical studies have shown that vestibular migraine patients exhibit abnormal sensitivity to vestibular stimuli that implicates central canal-otolith integration, rather than isolated peripheral vestibular dysfunction.3 The overlap between migraine circuits and central vestibular pathways further reinforces the central origin, with the trigeminovascular system and brainstem nuclei playing key roles in symptom generation.4 Regarding the definition of vestibular migraine, there is substantial heterogeneity in clinical presentations. The diagnostic criteria jointly proposed by the Bárány Society and the International Headache Society require a history of migraine and vestibular symptoms that are temporally associated with migraine features; however, they do not, for example, distinguish between separate vestibular episodes in patients with a history of migraine and vestibular complaints occurring during the migraine aura or headache phase.5 Recent cluster analyses and large cohort studies have identified multiple subgroups within vestibular migraine, with variable symptom profiles, attack durations, and associated features, indicating that the current diagnostic entity likely encompasses a heterogeneous group of patients with different underlying mechanisms.6,7 This heterogeneity complicates both diagnosis and management, and underscores the need for further research to refine the classification and understanding of vestibular migraine. In summary, disorders unrelated to vestibular migraine do not provide evidence for a peripheral origin of vestibular migraine, and the current definition likely includes a diverse patient population with both central and peripheral features, but with predominant central pathophysiology.

Objective:Hand and arm functions have been associated with cognition in healthy young and older adults (Vasylenko et al., 2018) and in patients with Parkinson's disease (Bezdicek et al., 2014). Music training has been proposed to integrate motor and cognitive functions by engaging motoric, sensory, perceptual, and various cognitive domains (Wan &amp; Schlaug, 2010). In this study, we examined if performance on fine and gross motor tasks is predicted by cognitive measures of memory, attention, and executive functions, and whether this relationship varies by the extent of musical training in healthy young participants.Participants and Methods:Forty five healthy young participants were recruited (M = 22.32, SD = 4.10; 78% female). Participants completed fine (Grooved pegboard) and gross motor (Box and Blocks) measures as well as cognitive measures (Rey auditory verbal learning test, Stroop, Trail making, and D2 cancellation), and the musical training subscale of the Goldsmith Musical Sophistication Index. Two multiple regression models were conducted assessing cognitive measures as predictors of fine and gross motor functions, with musical training as a covariate in both models.Results:Musical training was normally distributed across participants (M = 23.47, SD = 10.28). The results of the first model assessing the role of cognitive measures as predictors of fine motor function indicate a moderate fit (F(5,36) = 3.32, R = 0.55, explaining .32 of variance, p &lt; .05), with memory (B = 2.75, SE = 0.82, p &lt; .005) and sustained attention (B = 0.09, SE = 0.03, p &lt; .01) as moderate predictors. These cognitive measures were also found to predict gross motor function (F(5,36) = 3.06, p &lt; .05, R = 0.55, explaining .30 of the variance), with memory retention (B = 2.49, SE = 0.83, p &lt; .001) and sustained attention (B = 0.07, SE = 0.03, p &lt; .05) as moderate predictors. In both models, musical training was not a significant predictor.Conclusions:We found that both fine and gross hand motor functions are predicted by cognitive measures of memory retention and sustained attention. Our results support previous findings associating cognition and motor function, with attention being relevant in young adults and memory a predictor in older adults (Vasylenko et al., 2018). We corroborate these findings for hand function, but did not find executive functions to be implicated, which were previously reported as a predictor only for older adults. While musical training has been suggested to enhance the cognitive-motor relationship as it involves motor skills as well as engages various cognitive domains (Wan &amp; Schlaug, 2010), prior musical training was not found to affect this relationship. While music background did not predict better hand motor function, it did account for more interpersonal variance. The results suggest that for most amateur musicians, including those with years of experience, musical training may not affect the association between cognition and both fine and gross hand motor skill. The current findings indicate that while musical training can be an enriching experience, it may not (exclusively) enhance motor-cognitive integration. Different outcomes may be found with more extreme levels of music training, or a different age group.

Analysis of video head impulse test saccades data in patients with vestibular migraine or probable vestibular migraine

BackgroundLung cancer patients have low survival rates resulting in over 131,000 deaths in the US in 2021. Muscle health decline from sarcopenia and cachexia increases the risk of death among patients with lung cancer. Though muscle mass is often used for sarcopenia diagnosis and non‐tissue specific weight loss is typically used for cachexia diagnosis, both conditions have no consensus definitions. Therefore, the need for quantitative biomarkers that reflect muscle health changes due to aging and weight loss is critical to mitigate sarcopenia and cachexia. We propose using highly accurate MRI‐based proton density fat fraction (PDFF) as a reference measure of muscle health to develop bedside ultrasound measures as biomarkers of muscle health. We hypothesized that PDFF is associated with ultrasound‐based echointensity (EI) and shear wave elastography (SWE), and that all three modalities are sensitive to muscle health differences between healthy young, healthy older, and older adults undergoing treatment for lung cancer.MethodsWe compared muscle health operationalized as myosteatosis in the mid‐thigh of the rectus femoris using ultrasound‐based brightness‐mode for EI, ultrasound‐based SWE for tissue elasticity, and MRI‐based PDFF for percent fat, which was the reference measure. We compared the 3 measures among young healthy (n=10), older healthy (n=10), and older adults with non‐small cell lung cancer (n=10) in a cross‐sectional pilot study. We also compared non‐myosteatosis measures including subcutaneous adipose tissue thickness and rectus femoris thickness via ultrasound, whole‐leg cross‐sectional area via MRI, and BMI between groups and between myosteatosis measures. We used ANOVAs with Tukey post‐hoc comparisons to assess muscle health between groups and Pearson correlations to determine muscle health measure associations between imaging modalities.ResultsWe found young healthy adults had significantly lower PDFF than older healthy adults and older adults with lung cancer (0.33% vs 2.83% vs 2.93%, respectively; p=0.001). Young adults also had significantly lower EI than older healthy adults, but not older adults with cancer (48.58 vs 81.81 vs 75.35; p=0.008). When comparing between measures, PDFF was highly associated with EI (r=0.62, p&lt;0.001) and moderately inversely associated with SWE (r=‐0.41, p=0.025) but not BMI, rectus femoris thickness, or rectus femoris cross‐sectional area.ConclusionPDFF was sensitive to myosteatosis differences between young and both older adult groups. EI was less sensitive to myosteatosis differences between groups, yet EI was highly associated with PDFF unlike BMI. Our results suggest that the ultrasound measures could serve to determine muscle health at the bedside and are more sensitive to muscle health differences than BMI, which could improve interventions for cachexia and patient outcomes.

The head-impulse test (HIT) is an important test for examining unilateral vestibular hypofunction. The new video-head-impulse test (vHIT) is more sensitive and specific than the clinical bedside-head-impulse test (bHIT). Alternatively, one can test for vestibular hypofunction with the caloric irrigation test. Various studies showed that both tests may not always identify vestibular hypofunction; instead, the results of the tests might be contradictory. To evaluate the diagnostic value of these tests, we routinely measured patients exhibiting vertigo or dizziness at our community hospital with bithermal caloric irrigation, the bHIT and the vHIT. Only those patients (n = 172) with a pathological caloric irrigation test of more than 25 % unilateral weakness in the Jongkee's formula were included. Out of these patients, 41 % had a pathologic vHIT. Among the subgroup with acute symptoms (symptom onset within 5 days), 63 % had a pathological video-head-impulse, whereas only 33 % of the non-acute group (symptom onset more than 5 days) tested pathological. A pathological HIT depended on the disease stage, the amount of unilateral weakness in caloric examination and on the test itself.

The purposes of this study was to elucidate the clinical characteristics of patients suffering from migraine-associated vertigo (MAV) including results of cervical vestibular evoked myogenic potential (cVEMP) and ocular VEMP (oVEMP). Thirty patients diagnosed as having MAV based on the diagnostic criteria by Sakata et al. were enrolled. We performed a retrospective chart review. These patients underwent medical history taking and examinations including cVEMP, oVEMP and a caloric test. All examinations were performed during a symptom-free interval. Twenty one patients (70%) experienced rotatory vertigo, 5 patients (17%) had floating dizziness and 4 patients (13%) had both. Twenty six patients (87%) reported tinnitus and/or aural fullness unilaterally or bilaterally. Their vertigo or dizziness lasted under 60 minutes in 10 patients (34%), 1 hour to 24 hours in 14 patients (46%), and over one day in 5 patients (17%). Canal paresis in the caloric test was observed in 5 patients (17%). Concerning cVEMP, 4 of the 30 patients (13%) showed absent cVEMPs bilaterally, 2 patients (7%) showed absent cVEMPs reflexes unilaterally, and one (3%) demonstrated decreased cVEMP amplitudes unilaterally. Only one patient showed prolonged cVEMP latencies. Concerning oVEMP, 6 of the 30 patients (20%) had absent oVEMP reflexes bilaterally, 2 (7%) had absent oVEMP reflexes unilaterally, and one (3%) had decreased oVEMP amplitudes unilaterally. In 2 patients prolonged oVEMP latencies were observed. No significant correlation was observed among cVEMP, oVEMP and the caloric test. This study showed abnormal vestibular reflexes could be shown by oVEMP as well as the caloric test and cVEMP. It was suggested that a portion of those patients with MAV have abnormal otolith-ocular reflexes.

Background and ObjectivesZZThe purpose of this study was to verify if high vestibulo-ocular reflex (VOR) gain in slow harmonic acceleration (SHA) test can be considered as a hallmark of a distinct disease entity. We hypothesized that patients with high VOR gain in the SHA test can be classified as a distinct disease group and looked for evidence that can support this hypothesis. Subjects and MethodZZFor this study, 306 patients who had undergone a rotation chair test were enrolled. We checked other VOR measurements (caloric test and step velocity) and clinical manifestation of the patients with high gain in SHA (HG group). The data were compared to those of the migraine associated vertigo (MAV), benign recurrent vertigo (BRV) and psychogenic dizziness (PsyD). ResultsZZAn abnormally long time constant and a large response to the caloric test were found more frequently in the patient group with high gain in SHA. The incidence of high gain in SHA was significantly higher in MAV, BRV and PsyD. The clinical manifestation of HG group was not distinguishable from the effects of BRV and PsyD. But MAV was different from HG group. ConclusionZZWe failed to find any evidence that the patients with high gain in the SHA could be classified as a distinct disease group. It seems that high gain is not merely a non-specific or incidental finding but a reproducible finding that reflects an aspect of the subject’s vestibular function. Also, the high gain in SHA is more suggestive of BRV or PsyD than MAV. Korean J Otorhinolaryngol-Head Neck Surg 2009;52:874-9 Key WordsZZHigh gain·Vestibulo-ocular reflex·Rotation chair test·Sinusoidal harmonic acceleration test.

Differences in vestibulo-ocular reflex time constants in patients with vestibular migraine versus vestibular neuritis/labyrinthitis

Multiomics Characterization of Normal CD34+ Hematopoietic Progenitor Cells (HPC) and Blasts in the Bone Marrow (BM) and Peripheral Blood (PB) of Patients with Acute Myeloid Leukemia (AML)

Despite growing evidence on the effectiveness of vestibular rehabilitation (VR) in several vestibular pathologies, data on its impact in patients with vestibular migraine (VM) remain relatively limited. The aim of this study was to evaluate the effects of VR on balance, dizziness severity, sleep quality and quality of life in patients diagnosed with VM. Forty eight patients diagnosed with VM were randomized into two groups: a control group receiving routine medical treatment and an intervention group receiving medical treatment plus an eight-week structured VR program. Participants were assessed for dizziness severity using a Visual Analog Scale (VAS), for balance using balance tests, for sleep quality using the Pittsburgh Sleep Quality Index (PSQI), and for handicap-related quality of life using the Dizziness Handicap Inventory (DHI), at baseline and at the end of the 8-week treatment. A total of 40 VM patients completed the study. The majority of the participants were female (85%). The intervention group showed significant improvements in static and dynamic balance tests, PSQI, dizziness-related DHI, and dizziness severity (VAS) from baseline to post-intervention (p < 0.05), whereas the control group showed no meaningful changes. Repeated measures ANOVA revealed significant group × time interactions across balance, functional mobility (TUG), sleep quality, and dizziness outcomes (p < 0.05), indicating greater improvements in the intervention group compared with controls. An eight-week structured VR program combined with routine medical treatment significantly improved balance, reduced dizziness severity and dizziness-related disability, and enhanced sleep quality in patients with VM.

The purpose of this study is to investigate characteristics of nystagmus during attacks of vestibular migraine (VM), and to find a distinct clinical feature compared to other migraine and peripheral vestibular disorders. Methods: This study is a retrospective chart review of 82 patients satisfied with VM criteria, which is formulated by the new Brny Society. Spontaneous and positional nystagmus provoked by various head positions were examined with video-nystagmography in all patients. Bithermal caloric test and cervical vestibular evoked myogenic potential test (cVEMP) were also performed. The direction and peak slow-phase velocity (SPV) of nystagmus, unilateral caloric weakness and interaural difference of cVEMP were analyzed. Control groups were lesion side in acute VN for nystagmus results and healthy side in the patients with benign paroxysmal positional vertigo of posterior semicircular canal for caloric and cVEMP results. Chi-square test and Mann-Whitney U-test were used for statistical analysis. Results: During the acute attack, nystagmus was seen in 71.9% (59 of 82) of patients. Horizontal nystagmus was the predominant type. Peak SPV in VM patients was much slower than in the control group (2.371.73 /sec vs. 17.0512.69 /sec, p0.0001). There was no significant difference on the result of both caloric and cVEMP test, compared to those of control groups. Conclusion: Nystagmus with horizontal directions and low SPV was dominant form in the attack of VM. Close observation of nystagmus can be helpful to make a correct diagnosis and to understand the pathomechanism of vertigo in VM.

Video Analysis of Sagittal Spinal Posture in Healthy Young and Older Adults