Assessing fall risk and equilibrium function in patients with age-related macular degeneration and glaucoma: An observational study.

BACKGROUND: Falls in older adults are a significant public health concern, and age-related macular degeneration (AMD) and glaucoma have been identified as potential visual risk factors. This study was designed to assess equilibrium function, fall risk, and fall-related self-efficacy (an individual's belief in their capacity to act in ways necessary to reach specific goals) in patients with AMD and glaucoma. METHODS: This observational study was performed at the Otorhinolaryngology Department of Shinseikai Toyama Hospital. The cohort comprised 60 participants (AMD; n = 30; median age, 76.0 years; and glaucoma; n = 30; median age, 64.5 years). Visual acuity and visual fields were assessed using the decimal best-corrected visual acuity and Humphrey visual field tests, respectively. The evaluation metrics included pathological eye movement analysis, bedside head impulse test, single-leg upright test, eye-tracking test, optokinetic nystagmus, and posturography. Furthermore, we administered questionnaires for fall risk determinants including the Dizziness Handicap Inventory, Activities-Specific Balance Confidence Scale, Falls Efficacy Scale-International, and Hospital Anxiety and Depression Scale. The collected data were analyzed using descriptive statistics, and Spearman's correlation analysis was employed to examine the interrelations among the equilibrium function, fall risk, and other pertinent variables. RESULTS: Most participants exhibited standard outcomes in equilibrium function evaluations. Visual acuity and field deficits had a minimal impact on subjective dizziness manifestations, degree of disability, and fall-related self-efficacy. Both groups predominantly showed high self-efficacy. No significant correlation was observed between visual acuity or field deficits and body equilibrium function or fall risk. However, greater peripheral visual field impairment was associated with a tendency for sensory reweighting from visual to somatosensory. CONCLUSION: Self-efficacy was higher and fall risk was relatively lower among patients with mild-to-moderate visual impairment, with a tendency for sensory reweighting from visual to somatosensory in those with greater peripheral visual field impairment. Further studies are required to validate these findings.

Performance of GPT-4V in Answering the Japanese Otolaryngology Board Certification Examination Questions: Evaluation Study.

BACKGROUND: Artificial intelligence models can learn from medical literature and clinical cases and generate answers that rival human experts. However, challenges remain in the analysis of complex data containing images and diagrams. OBJECTIVE: This study aims to assess the answering capabilities and accuracy of ChatGPT-4 Vision (GPT-4V) for a set of 100 questions, including image-based questions, from the 2023 otolaryngology board certification examination. METHODS: Answers to 100 questions from the 2023 otolaryngology board certification examination, including image-based questions, were generated using GPT-4V. The accuracy rate was evaluated using different prompts, and the presence of images, clinical area of the questions, and variations in the answer content were examined. RESULTS: The accuracy rate for text-only input was, on average, 24.7% but improved to 47.3% with the addition of English translation and prompts (P<.001). The average nonresponse rate for text-only input was 46.3%; this decreased to 2.7% with the addition of English translation and prompts (P<.001). The accuracy rate was lower for image-based questions than for text-only questions across all types of input, with a relatively high nonresponse rate. General questions and questions from the fields of head and neck allergies and nasal allergies had relatively high accuracy rates, which increased with the addition of translation and prompts. In terms of content, questions related to anatomy had the highest accuracy rate. For all content types, the addition of translation and prompts increased the accuracy rate. As for the performance based on image-based questions, the average of correct answer rate with text-only input was 30.4%, and that with text-plus-image input was 41.3% (P=.02). CONCLUSIONS: Examination of artificial intelligence's answering capabilities for the otolaryngology board certification examination improves our understanding of its potential and limitations in this field. Although the improvement was noted with the addition of translation and prompts, the accuracy rate for image-based questions was lower than that for text-based questions, suggesting room for improvement in GPT-4V at this stage. Furthermore, text-plus-image input answers a higher rate in image-based questions. Our findings imply the usefulness and potential of GPT-4V in medicine; however, future consideration of safe use methods is needed.

Development of a Prototype Video Head Impulse Test System Using an iPhone for Screening of Peripheral Vestibular Dysfunction.

Introduction: Head impulse, nystagmus, and test of skew (HINTS) is more accurate for the early diagnosis of occipital fossa stroke than magnetic resonance imaging. However, the head impulse test (HIT) is relatively challenging to perform, as it is subjective. Herein, we developed a prototype video HIT (vHIT) system using an iPhone (Apple, Cupertino, CA, USA) that is compact, easy to operate, and analyzable by our iPhone application. Methods: The iPhone-vHIT and a vHIT using EyeSeeCam (Interacoustics, Eden Prairie, NM, USA) were performed on a healthy man in his 30s and on a patient with vestibular neuritis who visited the Mejiro University Ear Institute Clinic. For the iPhone-vHIT, eye movements were detected by analyzing high-speed videos captured using an iPhone camera, and head movements were followed using an iPhone gyro sensor. An iPhone fixation brace was used to capture the video without any blurring. Results: The iPhone-vHIT system obtained vHIT waveforms similar to those of the EyeSeeCam-vHIT system in the healthy man and the patient with vestibular neuritis. The iPhone-vHIT system effectively detected the reduced vestibulo-ocular reflex gain in patients with vestibular neuritis. The iPhone-vHIT system at 120 frames per second was less sensitive to catch-up saccades than the EyeSeeCam. Conclusion: vHIT systems using a smartphone have been reported but are currently unavailable. At present, the iPhone-vHIT application in this study is the only available smartphone-based vHIT system for screening of peripheral vestibular dysfunction. We believe that the prototype iPhone-vHIT with a high-speed camera will be clinically used to perform the vHIT, even though it only examines the lateral semicircular canal.

Smartphone-Assisted Medical Care for Vestibular Dysfunction as a Telehealth Strategy for Digital Therapy Beyond COVID-19: Scoping Review.

BACKGROUND: Dizziness and vertigo can be caused by various factors, such as peripheral vestibular and central disorders. Although consultations with specialists are advisable when necessary, patients with severe vertigo symptoms may have limited mobility, which may interfere with hospital visits. The spread of COVID-19 has further limited the number of hospital visits for patients with dizziness; therefore, a method of medical care that enables more accurate treatment under time and geographical constraints is needed. Telemedicine has become widespread, owing to the popularity of smartphone and tablet devices in recent years, and the use of devices and systems has made it possible to provide efficient medical care. However, no previous scoping review has mapped existing studies on telemedicine for vertigo and dizziness, and no recommendations have been made regarding which devices and systems should be used for specific diseases. OBJECTIVE: The aim of this review was to map and assess previous studies on the use of information communications technology, smartphones, and apps for treating patients with vertigo and discuss the added value of introducing telemedicine to improve the quality of medical care and create an environment that builds security and trust among patients. METHODS: A scoping review was conducted with the methodological framework of Arksey and O'Malley and in accordance with the of the PRISMA-ScR (Preferred Reporting Items for Systematic Reviews and Meta-Analysis extension for Scoping Reviews) guidelines. The PubMed, MEDLINE, and Cochrane Library databases were searched to retrieve previous reports on smartphone-assisted telemedicine treatment for vertigo published between January 2000 and May 2023. Two authors independently assessed eligibility and extracted data. RESULTS: This review included 20 papers that reported devices or systems for telemedicine for vestibular dysfunction. Among studies that reported the use of a device or app, 2 were related to anamnesis and subjective symptoms, 12 were related to objective examination, 7 were related to remote diagnosis, and 7 were related to treatment and rehabilitation. CONCLUSIONS: With the advancement of technology, the use of telemedicine in patients with dizziness may be feasible. In the future, it will be necessary to consider how telemedicine can be used in dizziness treatment and develop an effective treatment system combining in-person medical care and the effective use of devices for the management of severe vertigo and related diseases. The smooth introduction of telemedicine in vertigo treatment is expected to improve the quality of treatment, increase opportunities for patients to receive medical care, and reduce time and travel costs, leading to a sense of security and trust among patients.

Effects of Early Vestibular Rehabilitation in Patients With Acute Vestibular Disorder: A Systematic Review and Meta-Analysis.

OBJECTIVES: To investigate the effect of early vestibular rehabilitation on physical function and dizziness in patients with acute vestibular disorders. DATABASES REVIEWED: The electronic databases examined included PubMed (MEDLINE), Cochrane Central Register of Controlled Trials (CENTRAL), EMBASE (via Dialog), and PEDro. METHODS: The inclusion criteria in terms of the study participants were patients 20 years and older with an acute unilateral peripheral vestibular disorder. We included individual randomized controlled trials (RCTs), cluster-RCTs, quasi-RCTs, and crossover trials. The outcomes were gait, balance (eyes open, eyes close), activities of daily living, dizziness, and vestibular function. Early vestibular rehabilitation was defined as rehabilitation within 14 days of vestibular disorder onset or surgery. Main outcome measures were gait, balance (eyes open, eyes close), activities of daily living, dizziness, and vestibular function. RESULTS: Twelve trials involving 542 participants were included. Early vestibular rehabilitation improved the Dizziness Handicap Inventory by -7.18 (95% confidence interval [CI], -10.48 to -3.88), balance during eyes close by -1.40 (95% CI, -2.42 to -0.39), and dizziness by -1.47 (95% CI, -2.74 to -0.21) compared with no intervention or placebo. CONCLUSION: The present study demonstrated that early vestibular rehabilitation improved the Dizziness Handicap Inventory, balance (eyes close), and subjective dizziness in a patient with acute vestibular disorders. This result indicates that early vestibular rehabilitation can promote vestibular compensation.

A new portable Fresnel magnifying loupe for nystagmus observation: a clinical education and clinical practice setting study.

BACKGROUND: Dizziness is a common complaint of patients treated by primary care physicians. It is predominantly caused by peripheral vestibular disorders; however, central nervous system disorders should be excluded. Examination of the eye movements and nystagmus can help differentiate the disorders of the central nervous system from the peripheral vestibular disorders; however, it is often not performed appropriately. In medical education practice, nystagmus observation may facilitate an understanding of vestibular function and nystagmus characteristics. Thus, we proposed a medical education practice to master nystagmus observation using a recently developed portable Fresnel magnifying loupe that could be shielded by one eye. METHODS: Thirty-three students from the Department of Physical Therapy and the Department of Speech, Language, and Hearing Therapy of the Mejiro University participated in this study. Postrotatory nystagmus was measured and compared using the new loupe and control methods, namely the naked eye and Frenzel goggles; we rated the ease of visibility using a five-point scale. RESULTS: The number of detected cases of nystagmus was significantly higher with the new loupe than with the naked eye (p = 0.001). In addition, there were no significant differences in the nystagmus counts between the observations using the new loupe and Frenzel goggles (p = 0.087). No significant difference was observed in the visibility of eye movements between the loupe and naked eye (p = 1.00). The Frenzel goggles provided better visibility compared to that by the loupe (p = 0.034); however, none of the participants reported poor visibility using any of these methods. CONCLUSIONS: Our newly developed Fresnel loupe allows for the observation of nystagmus counts a level of reduction in fixation suppression similar to that of Frenzel goggles in an educational practice setting. Furthermore, it enables the detection of significantly more nystagmus counts compared to that by the naked eye. It offers several advantages over Frenzel goggles, including its lightweight, thin, durable, and portable design. Additionally, the loupe does not rely on a power source and can be used under normal room lighting conditions. TRIAL REGISTRATION: This study was approved by the Medical Research Ethics Committee of Mejiro University (approval number: 21medicine-021).

Clinical features of persistent postural-perceptual dizziness with isolated otolith dysfunction as revealed by VEMP and vHIT findings.

Background: Persistent postural-perceptual dizziness (PPPD) is a relatively new disease entity, with diagnostic criteria published by the Bárány Society. PPPD is often preceded by a peripheral or central vestibular disorder. It is not clear how coexisting deficits due to preceding vestibular disorders affect PPPD symptoms. Objective: This study aimed to characterize the clinical features of PPPD with or without isolated otolith dysfunction using vestibular function tests. Methods: The study included 43 patients (12 males and 31 females) who were diagnosed with PPPD and completed oculomotor-vestibular function tests. The Dizziness Handicap Inventory (DHI), Hospital Anxiety and Depression Scale (HADS), Niigata PPPD Questionnaire (NPQ), and Romberg test for stabilometry were examined. The 43 patients with PPPD were classified into four categories based on vestibular evoked myogenic potential (VEMP) and video head impulse test (vHIT) results: normal function for both semicircular canals and otoliths (normal), isolated otolith dysfunction (iOtoDys), isolated semicircular canal dysfunction (iCanalDys), and dysfunction of both otoliths and semicircular canals (OtoCanalDys). Results: Among the 43 patients with PPPD, the iOtoDys group was the largest (44.2%), followed by the normal group (37.2%), iCanalDys group (9.3%), and OtoCanalDys group (9.3%). Eight of the 19 iOtoDys patients showed both abnormal cVEMP and oVEMP responses unilaterally or bilaterally (both sacculus and utriculus damage type), whereas 11 showed either an abnormal cVEMP or an abnormal oVEMP response (either sacculus or utriculus damage type). In a three-group comparison of the both sacculus and utriculus damage type, the either sacculus or utriculus damage type, and the normal group, the mean total, functional, and emotional DHI scores were significantly higher for the both sacculus and utriculus damage type than for the either sacculus or utriculus damage type. The Romberg ratio, a measure of stabilometry, was significantly higher for the normal group than for the both sacculus and utriculus damage type and the sacculus or utriculus damage type in the iOtoDys group. Conclusions: The coexistence of sacculus and utriculus damage may exacerbate dizziness symptoms in patients with PPPD. Determining the presence and extent of otolith damage in PPPD may provide useful information on the pathophysiology and treatment strategies of PPPD.

Effect of Vestibular Rehabilitation Program Using a Booklet in Patients with Chronic Peripheral Vestibular Hypofunction: A Randomized Controlled Trial.

Objectives: This study investigated the effects of a supervised home-based vestibular rehabilitation program using a booklet on gait function and dizziness in patients with chronic peripheral vestibular hypofunction. Methods: This was a non-blinded, randomized, controlled trial. Patients (n=42) with chronic peripheral vestibular hypofunction were randomly divided into the vestibular rehabilitation group (VR group; n=20) or the control group (n=22). Patients in the VR group received a supervised home-based vestibular rehabilitation program using a booklet in addition to physician care for 4 weeks. The physical therapist checked the home program when the VR group visited the outpatient clinic once a week. Patients in the control group received physician care only during the trial period. The primary outcome was functional gait assessment (FGA). The secondary outcomes were the dynamic gait index (DGI) and the dizziness handicap inventory (DHI). Results: Two-way repeated measures analysis of variance showed a significant interaction for FGA, DGI, DHI total, and DHI emotional scores (P<0.05) with the VR group improving more than the control group. No significant interactions were found for DHI physical and DHI functional scores (P≥0.05). Conclusions: The home-based vestibular rehabilitation program in this study was effective in improving gait function and dizziness in patients with chronic peripheral vestibular hypofunction. Regular supervision may have improved adherence to home exercise and contributed to the effectiveness of vestibular rehabilitation.

Efficacy of supervised vestibular rehabilitation on functional mobility in patients with chronic vestibular hypofunction.

[Purpose] This study aimed to compare the effects of different intervention frequencies on walking ability and balance in patients with chronic unilateral vestibular hypofunction. [Participants and Methods] Participants included in this case-control study were assigned to one of two groups: the multiple-intervention (once a week) and single-intervention groups. Results for the Timed Up and Go test, Dynamic Gait Index, Functional Gait Assessment, and Activities-specific Balance Confidence scale were determined at baseline and four weeks after initiating the vestibular rehabilitation program. Thereafter, intra- and inter-group differences in the rates of change of these parameters were determined. [Results] The Timed Up and Go test values, Dynamic Gait Index, and Functional Gait Assessment scores improved significantly after four weeks in the multiple-intervention group. The improvement rate in the Timed Up and Go test differed significantly between the two groups. The Activities-specific Balance Confidence scale scores did not significantly change in either group after four weeks. [Conclusion] Compared to a single intervention, multiple interventions by a physical therapist produced significantly greater benefits in a relatively shorter period of time in patients with chronic unilateral vestibular hypofunction.

Prevalence and Risk Factors of Sarcopenia in Patients with Dizziness.

OBJECTIVE: This study aimed to investigate the prevalence of sarcopenia and factors associated with sarcopenia in patients with dizziness. STUDY DESIGN: This is a cross-sectional study. PATIENTS: A total of 162 patients 65 years or older with the chief complaint of dizziness or vertigo (dizziness group) and 132 community-dwelling elderly (control group) were recruited during their visit to the otolaryngology clinic between May 2020 and October 2021. RESULTS: Of the 162 patients with dizziness (dizziness group), 53 (32.7%) were classified as sarcopenia according to the 2019 criteria of the Asian Working Group for Sarcopenia. There were significant differences in the prevalence of sarcopenia between the dizziness group and the control group ( p < 0.01). The factors that significantly affected the sarcopenia, in order of greater odds ratio, were HADS_A, age, and DHI_Total (odds ratio = 1.223, 1.130, and 1.022, respectively). CONCLUSIONS: The present study shows that (i) the prevalence of sarcopenia in patients with dizziness is higher than a community-dwelling elderly; (ii) patients with dizziness and sarcopenia have higher DHI_functional, DHI_emotional, DHI_total, and HADS_A compared with patients with dizziness but without sarcopenia; and (iii) age, HADS_A, and DHI were associated with sarcopenia in patients with dizziness.

Factors affecting the outcome of vestibular rehabilitation in patients with peripheral vestibular disorders.

OBJECTIVE: Previous studies have reported that developmental, environmental, medical, psychological, visual, and other sensory-related factors can influence the outcome of vestibular rehabilitation. However, only a few studies have used patient's daily lives as the main outcome. In addition, in some studies, rehabilitation was not supervised by a physical therapist. This study aimed to determine the factors associated with the outcome of physical-therapist-supervised vestibular rehabilitation in patients with peripheral vestibular disorders, with the impact of dizziness on quality of life as the main outcome. METHODS: This retrospective cohort study included 47 patients with peripheral vestibular disorders. A physical therapist provided 40 min of vestibular rehabilitation once a week for 4 weeks. Age, sex, disease duration, Dizziness Handicap Inventory (DHI), Timed Up-and-Go test (TUG), Dynamic Gait Index (DGI), Functional Gait Assessment (FGA), Activity-Specific Balance Confidence Scale (ABC scale), and Hospital Anxiety and Depression Scale (HADS) were investigated. Multiple regression analysis was performed, with the DHI rate of change before and after the intervention as the objective variable. RESULTS: Vestibular rehabilitation improved all outcomes. In the multiple regression analysis, the ABC scale was identified as a factor that significantly influenced the DHI rate of change (ß = -0.428, p < 0.01). CONCLUSION: A higher ABC scale score was associated with a lower DHI rate of change (i.e., better improvement). Therefore, it may be important to assess psychological aspects, especially confidence in balance, when implementing vestibular rehabilitation in patients with peripheral vestibular disorders.

The utilization and demographic characteristics of in-hospital rehabilitation for acute vestibular neuritis in Japan.

OBJECTIVE: To investigate the utilization and demographic characteristics of in-hospital rehabilitation for patients with acute vestibular neuritis using the Japan Medical Data Center (JMDC) database. METHODS: We gathered information on patients that were at least 20 years of age who were admitted with a diagnosis of VN (ICD-10 code: H81.2). We defined in-hospital rehabilitation service use as payment of insurance claims for at least one session of rehabilitation during admission. RESULTS: We identified 809 patients that were eligible for this study; among these, 59 patients (7.3%) received rehabilitation while 750 patients did not. The median total time spent and the median time per day in inpatient rehabilitation were 140 min and 11.7 min, respectively. Factors that significantly affected the rehabilitation service use, in order of greater odds, were primary care, internal medicine, and age in multivariate logistic regression analysis (odds ratio = 4.42, 2.17, 1.33, respectively). CONCLUSIONS: This study showed that (1) utilization of rehabilitation services by acute patients with VN was low; and (2) age, admission to internal medicine, and admission to primary care were associated with the use of rehabilitation services.

Relationship between physical activity and dizziness handicap inventory in patients with dizziness -A multivariate analysis.

OBJECTIVE: A few studies have analyzed the physical activity in patients with dizziness. Levels of physical activity using 3-axial accelerometer were reported to be lower in patients with chronic dizziness compared to healthy adults. However, the sample size was small and confounding factors were not adjusted in the study. As the age, balance, anxiety, and depression likely contribute to dizziness, the contribution of physical activity to dizziness should be evaluated after adjusting for these potential confounders. We investigated the relationship between physical activity, postural stability, anxiety, and handicap in patients with dizziness using multivariate analysis. METHODS: This cross-sectional study included 59 patients with dizziness. The physical activity was measured using a 3-axial accelerometer. We also assessed the Dizziness Handicap Inventory (DHI), Hospital and Anxiety and Depression Scale (HADS), and the total center of pressure path length eyes open and eyes closed (COP_EO, COP_EC). To be eligible for analysis, the participants were required to wear the accelerometer for at least four days, with at least 10 h/day of wear time each day. RESULTS: There were significant differences in the light physical activity (LPA) and moderate to vigorous intensity physical activity (MVPA) between the mild (DHI ≦30) and severe (DHI > 60) groups. Factors that significantly affected the DHI_T score, in order of greater ß, were LPA, COP_EC, female, and HADS_A (ß = -0.546, 0.459, 0.437, 0.239, respectively). CONCLUSIONS: The present study demonstrated that the patients in the severe group had shorter LPA and MVPA times than that of the patients in the mild group. Additionally, LPA was associated with DHI_T in patients with dizziness. Therefore, physical activity, especially LPA (e.g., activities of daily living), may need to be assessed in patients with dizziness.

Dizziness in peri- and postmenopausal women is associated with anxiety: a cross-sectional study.

BACKGROUND: Although dizziness is one of the most common symptoms of menopause, the underlying mechanism is not precisely known. Therefore, this study aimed to investigate the prevalence of, and the factors associated with, dizziness in peri- and postmenopausal women. METHODS: We conducted a cross-sectional study in which we analyzed the first-visit records of 471 Japanese women aged 40 to 65 years who enrolled in a health and nutrition education program at a menopause clinic. The prevalence of dizziness was estimated according to the participants' responses to the Menopausal Health-Related Quality of Life Questionnaire. The background characteristics of age, menopause status, body composition, cardiovascular parameters, basal metabolism, and physical fitness; other menopausal symptoms, including vasomotor, insomnia, depression, and anxiety symptoms; and lifestyle characteristics were assessed for their associations with dizziness. RESULTS: The percentage of women who suffered from dizziness once a week or more frequently was 35.7%. Compared to the women without dizziness, those with the symptom were younger; had a higher body weight, body mass index, body fat percentage, muscle mass, and waist-to-hip ratio; had higher systolic pressure; were slower in reaction time; had higher physical and psychological symptom scores of menopause; exercised less regularly; and consumed less alcohol. A multivariate logistic regression analysis revealed that the anxiety symptom, which was evaluated by the Hospital Anxiety and Depression Scale, was the sole factor that was independently associated with dizziness (adjusted odds ratio 1.14; 95% confidence interval 1.08-1.20). CONCLUSIONS: Dizziness is highly prevalent in Japanese peri- and postmenopausal women and it is associated with anxiety. The treatment of anxiety in this population might improve the symptom.

Adaptation of the vertical vestibulo-ocular reflex in cats during low-frequency vertical rotation.

OBJECTIVE: We examined plastic changes in the vestibulo-ocular reflex (VOR) during low-frequency vertical head rotation, a condition under which otolith inputs from the vestibular system are essential for VOR generation. METHODS: For adaptive conditioning of the vertical VOR, 0.02Hz sinusoidal pitch rotation for one hour about the earth's horizontal axis was synchronized with out-of-phase vertical visual stimulation from a random dot pattern. RESULTS: A vertical VOR was well evoked when the upright animal rotated around the earth-horizontal axis (EHA) at low frequency due to the changing gravity stimulus and dynamic stimulation of the otoliths. After adaptive conditioning, the amplitude of the vertical VOR increased by an average of 32.1%. CONCLUSION: Our observations showing plasticity in the otolithic contribution to the VOR may provide a new strategy for visual-vestibular mismatch training in patients with otolithic disorders. This low-frequency vertical head rotation protocol also provides a model for investigating the mechanisms underlying the adaptation of VORs mediated by otolith activation.

Sleep-stage correlates of hippocampal electroencephalogram in primates.

It has been demonstrated in the rodent hippocampus that rhythmic slow activity (theta) predominantly occurs during rapid eye movement (REM) sleep, while sharp waves and associated ripples occur mainly during non-REM sleep. However, evidence is lacking for correlates of sleep stages with electroencephalogram (EEG) in the hippocampus of monkeys. In the present study, we recorded hippocampal EEG from the dentate gyrus in monkeys overnight under conditions of polysomnographical monitoring. As result, the hippocampal EEG changed in a manner similar to that of the surface EEG: during wakefulness, the hippocampal EEG showed fast, desynchronized waves, which were partly replaced with slower waves of intermediate amplitudes during the shallow stages of non-REM sleep. During the deep stages of non-REM sleep, continuous, slower oscillations (0.5-8 Hz) with high amplitudes were predominant. During REM sleep, the hippocampal EEG again showed fast, desynchronized waves similar to those found during wakefulness. These results indicate that in the monkey, hippocampal rhythmic slow activity rarely occurs during REM sleep, which is in clear contrast to that of rodents. In addition, the increase in the slower oscillations of hippocampal EEG during non-REM sleep, which resembled that of the surface EEG, may at least partly reflect cortical inputs to the dentate gyrus during this behavioral state.

A low-grade chondrosarcoma presenting as an unusual cervical mass in the hyoid bone: a case report.

INTRODUCTION: A chondrosarcoma originating from the hyoid bone is very rare. Here, we describe a case of low-grade chondrosarcoma of hyoid origin and discuss its preoperative imaging features, including those on positron emission tomography-computed tomography, and its recurrence rate. CASE PRESENTATION: A 42-year-old Japanese man noticed a mass in the right submandibular region of his neck. A hard 3.0 × 2.8 cm tumor was noted on the right side of his hyoid bone. The mass was immobile and moved with deglutition. CONCLUSION: Even though radiographic studies, including positron emission tomography-computed tomography, were inconclusive, the cartilaginous tumor was surgically removed en bloc, and the tumor was diagnosed based on the results of pathological investigations. Close follow-up is recommended in such cases due to the potential for recurrences, because local recurrence occurred in 50% of the reported cases of grade one chondrosarcomas.

Respiratory involvement in IgG4-related Mikulicz's disease.

'Immunoglobulin G4 (IgG4)-related disease' is a new clinical concept of multi-organ diseases, with Mikulicz's disease (MD) being a clinical phenotype of IgG4-related disease. To clarify the clinical characteristics of respiratory involvement associated with IgG4-related MD, we retrospectively assessed 25 patients with MD, 11 (44%) of whom had allergic symptoms, and 7 (28%) of whom complained of respiratory problems. Thirteen patients (52%) presented with pulmonary and/or mediastinal lesions (P-MD) on chest computed tomography (CT), and 11 (44%) had lesions limited to the lacrimal and/or salivary glands (L-MD). Mean serum total protein, IgG, and IgG4 concentrations were significantly higher and CH50 was significantly lower in the P-MD than in the L-MD group. Immune complex was present only in the P-MD group. Chest CT images showed bronchial wall thickening, consolidation, nodule(s), interlobular thickening, ground glass opacity, pleural thickening/effusion, and mediastinal lymphadenopathy. Five of seven patients who underwent histological examination of the lungs had abundant IgG4-positive plasma cell infiltrates (IgG4/IgG-positive plasma cells >40%), but the other two did not. These findings suggest that respiratory lesions are not rare in patients with IgG4-related MD, and that they present with various manifestations. IgG4-related MD should be differentiated from similar diseases, such as sarcoidosis, bronchial asthma, Sjögren's syndrome, and malignant lymphoma.

Short-term synaptic plasticity in the dentate gyrus of monkeys.

The hippocampus plays an important role in learning and memory. Synaptic plasticity in the hippocampus, short-term and long-term, is postulated to be a neural substrate of memory trace. Paired-pulse stimulation is a standard technique for evaluating a form of short-term synaptic plasticity in rodents. However, evidence is lacking for paired-pulse responses in the primate hippocampus. In the present study, we recorded paired-pulse responses in the dentate gyrus of monkeys while stimulating to the medial part of the perforant path at several inter-pulse intervals (IPIs) using low and high stimulus intensities. When the stimulus intensity was low, the first pulse produced early strong depression (at IPIs of 10-30 ms) and late slight depression (at IPIs of 100-1000 ms) of field excitatory postsynaptic potentials (fEPSPs) generated by the second pulse, interposing no depression IPIs (50-70 ms). When the stimulus intensity was high, fEPSPs generated by the second pulse were depressed by the first pulse at all IPIs except for the longest one (2000 ms). Population spikes (PSs) generated by the second pulse were completely blocked or strongly depressed at shorter IPIs (10-100 or 200 ms, respectively), while no depression or slight facilitation occurred at longer IPIs (500-2000 ms). Administration of diazepam slightly increased fEPSPs, while it decreased PSs produced by the first pulse. It also enhanced the facilitation of PSs produced by the second stimulation at longer IPIs. The present results, in comparison with previous studies using rodents, indicate that paired-pulse responses of fEPSPs in the monkey are basically similar to those of rodents, although paired-pulse responses of PSs in the monkey are more delayed than those in rodents and have a different sensitivity to diazepam.