Search Results (46)

Motivation: Benign paroxysmal positional vertigo (BPPV) is characterized by torsional nystagmus induced by changes in head position, where accurate quantitative assessment of subtle torsional eye movements is essential for precise diagnosis. Conventional videonystagmography (VNG) techniques face challenges in accurately capturing the rotational components of pupil movements, and existing automated methods typically exhibit limited performance in identifying torsional nystagmus. Methodology: The objective of this study was to develop an automated system capable of accurately and quantitatively detecting torsional nystagmus. We introduce the Torsion Transformer model, designed to directly estimate torsion angles from iris images. This model employs a self-supervised learning framework comprising two main components: a Decoder module, which learns rotational transformations from image data, and a Finder module, which subsequently estimates the torsion angle. The resulting torsion angle data, represented as time-series, are then analyzed using a 1-dimensional convolutional neural network (1D-CNN) classifier to detect the presence of nystagmus. The performance of the proposed method was evaluated using video recordings from 127 patients diagnosed with BPPV. Findings: Our Torsion Transformer model demonstrated robust performance, achieving a sensitivity of 89.99%, specificity of 86.36%, an F1-score of 88.82%, and an area under the receiver operating characteristic curve (AUROC) of 87.93%. These results indicate that the proposed model effectively quantifies torsional nystagmus, with performance levels comparable to established methods for detecting horizontal and vertical nystagmus. Thus, the Torsion Transformer shows considerable promise as a clinical decision support tool in the diagnosis of BPPV. Key Findings: Technical performance improvement in torsional nystagmus detection; System to support clinical decision-making for healthcare professionals. Full article

Objective: To investigate the inter-method agreement between in-person consultations and video recordings when diagnosing BPPV. Methods: Two experienced vestibular clinicians (clinician A and B) evaluated patients for the presence and type of BPPV, using the TRV chair (Interacoustics, Middlefart, DK), at a tertiary referral center. During these in-person consultations, diagnostic maneuvers and eye movements were recorded, and a diagnosis was made. Both clinicians independently evaluated their cases again, during two video review sessions (Video Review 1 and Video Review 2). These sessions were conducted one month apart. Both clinicians were blinded to patient information and medical history during the analysis and did not have access to sound recordings. They were asked to provide a new diagnosis, based on the videos alone. Inter-method and intra-observer agreement for BPPV diagnoses between in-person consultations and video reviews were assessed using the percentage of agreement and Cohen’s kappa. An independent analysis of all patients’ eye movements was conducted to identify patterns that might have influenced agreement between in-person consultation diagnoses and the two video reviews by clinicians. Results: During the in-person consultations, each clinician evaluated 100 patients. Clinician A diagnosed BPPV in 40% of the cases, while clinician B diagnosed it in 19% of the cases. Considering the inter-method agreement, clinician A agreed on 81% (95% CI (73, 89)) and 77% (95% CI (69, 85)) of the cases with associated kappa coefficients of 0.67 (95% CI (0.55, 0.79)) and 0.63 (95% CI (0.51, 0.75)) between in-person consultations and Video Reviews 1 and 2, respectively. For clinician B, the percentages of agreement were, respectively, 86% (95% CI (79, 93)) and 84% (95% CI (77, 91)), with corresponding kappa coefficients of 0.55 (95% CI (0.36, 0.74)) and 0.51 (95% CI (0.32, 0.70)). As for the intra-observer agreement, clinician A achieved an intra-observer agreement of 84% (95% CI (77, 91)) with kappa = 0.74 (95% CI (0.63, 0.85)), while clinician B achieved a slightly higher intra-observer agreement of 90% (95% CI (84, 96)) with kappa = 0.67 (95% CI (0.51, 0.83)). Descriptive analysis of the eye movement revealed that both clinicians showed high diagnostic consistency for “no BPPV” in cases without provoked nystagmus (78/86, 91%) even when spontaneous nystagmus was present, and for posterior canal BPPV (37/78, 47%) when characteristic nystagmus was observed. However, disagreement was noted for horizontal canal BPPV (15 cases) and in scenarios with subjective BPPV (2 cases) or purely vertical nystagmus (11/31 cases, 35%). Conclusions: This study showed the feasibility of using video recordings when diagnosing BPPV. It demonstrates that BPPV might be reliably diagnosed in a telemedicine setting. However, careful consideration must be given to certain factors during the protocol’s design to improve the diagnostic process. Full article

Dr. Epley has been instrumental in defining the mechanisms and treatment of BPPV variants, including those of the horizontal canals. Cupulolithiasis is a horizontal canal BPPV variant usually defined as direction-changing apogeotropic nystagmus. In recent years, the favored cupulolithiasis mechanism of otoconia adhering persistently to the cupula has been called into question. Epley was the first to propose mechanistic theories which better match the most recent evidence. From the beginning, he has demonstrated mastery over the semicircular canal pathology and otoconial mechanics. Full article

Background/Objectives: To simplify diagnosing congenital and acquired nystagmus using fundus photographs. Methods: A retrospective study included patients with congenital or childhood-acquired nystagmus examined at a hospital-based ophthalmology clinic (September 2020–September 2023) with fundus photos taken. Exclusions were for incomplete data or low-quality images. Demographics, aetiology, orthoptic measurements, and ophthalmologic and neurological exams were reviewed. Two independent physicians graded fundus photos based on amplitude (distance between “ghost” images), the number of images visible, and the direction of nystagmus. Severity was rated on a 0–3 scale using qualitative and quantitative methods. Photographic findings were compared to clinical data, and statistical analysis used Mann-Whitney tests. Results: A total of 53 eyes from 29 patients (16 females, 13 males; mean age 12.5 years, range 3–65) were studied: 25 with binocular nystagmus and 3 with monocular nystagmus. Diagnoses included congenital (n = 15), latent-manifest (n = 3), neurologically associated (n = 2), and idiopathic (n = 9). Types observed were vertical (n = 5), horizontal (n = 23), rotatory (n = 10), and multidirectional (n = 15). Visual acuity ranged from 20/20 to no light perception. Fundus photos correlated with clinical diagnoses, aiding qualitative assessment of direction and amplitude and mitigating eye movement effects for clearer retinal detail visualization. Conclusions: Fundus photography effectively captures nystagmus characteristics and retinal details, even in young children, despite continuous eye movements. Integrating fundus cameras into routine practice may enhance nystagmus diagnosis and management, improving patient outcomes. Full article

Background/Objectives: Spontaneous nystagmus during vertigo attacks of Menière’s disease has been essentially described as horizontal, beating ipsilaterally (irritative type) or contralaterally (deficit type) to the hearing loss. Our main objective was to describe the characteristics of nystagmus during vertigo attacks. The second objective was to determine the feasibility of self-video recording of eye movements by a mobile phone. The third objective was to discuss the therapeutic implications of the observed nystagmus. Methods: We selected patients with definite Menière’s disease according to the Barany Society. Patients were video-recorded during their attacks by videonystagmoscopy (by the physician) and/or mobile phone (by the patient or immediate surroundings). Results: Seventeen patients were video-recorded by mobile phone (n = 8) or videonystagmoscopy (n = 8) or both (n = 1). The nystagmus was horizontal in 14 patients of the irritative type (n = 7) and of the deficit type (n = 5) or changed from the deficit to the irritative type (n = 2). The nystagmus was vertical in three patients, either down-beating (n = 2) or up-beating (n = 1). This vertical nystagmus changed to a more classical horizontal nystagmus in two patients. Conclusions: The direction of the nystagmus was variable and mostly horizontal, although it could be vertical and could change direction. Thus, the direction of the nystagmus has no value in deducing the affected side of Menière’s disease, which essentially relies on hearing dysfunction. The nystagmus could be video-recorded by a mobile phone, which was objective proof of the impact on daily life. This was a helpful therapeutic aid, particularly when chemical labyrinthectomy was considered. Full article

Introduction and Objectives: Skull vibration-induced nystagmus (SVIN) has become a validated tool for evaluating the vestibular function. The presence of SVIN is a useful indicator of the asymmetry of vestibular function between the two ears. In unilateral vestibular loss, a 100 Hz bone-conducted vibration given to either mastoid immediately causes a primarily horizontal nystagmus. The aim of this study is to review the usefulness of this tool in different clinical situations according to the results published. Methods: We performed an electronic search using PubMed and BVS. Eleven studies were discussed. Results: A progressive linear relationship has been identified between the slow-phase velocity (SPV) of SVIN determined using a 100 Hz skull vibrator and the gain difference (healthy ear/affected ear) measured by video head impulse test (vHIT). The SPV of SVIN may be more sensitive than vHIT in identifying the recovery of vestibular function following intratympanic gentamicin (ITG) administration. A link between a reduction in SPV and the likelihood of vertigo episodes in patients with MD who have been treated with intraympanic gentamicin (ITG) has been illustrated. SVIN in superior canal dehiscence (SCD) patients has greater sensitivity than the air-conducted Tullio phenomenon (ACTP) or the Hennebert sign. SVIN can be combined with vHIT to reveal vestibular asymmetry in nonprogressive vestibular schwannomas. An upbeating SVIN may reveal superior branch vestibular neuritis. Vibration-induced downbeat nystagmus should be added to the list of central vestibular signs and is likely due to cerebellar dysfunction. Conclusions: SVIN has become an interesting screening tool for diagnosing or during the follow-up of many different vestibular pathologies. Full article

Background: The SUPV3L1 gene encodes ATP-dependent RNA helicase SUPV3L1, which is a part of the mitochondrial degradosome complex or SUV3. SUPV3L1 unwinds secondary structures of mitochondrial RNA (mtRNA) and facilitates the degradation of mtRNA molecules. A nonsense homozygous variant in the SUPV3L1 gene was recently associated with mitochondrial disease. Our study presents the second documented case of SUPV3L1 pathology in humans. Methods: Whole-genome sequencing was performed on the NovaSeq 6000 platform using pair-end reading. Data analysis was performed with an in-house developed pipeline. Results: The 17-year-old female patient exhibited a diverse array of symptoms, including ataxia, spastic paraparesis, cognitive deficit, optic atrophy, and horizontal gaze-evoked nystagmus. Early onset of symptoms, such as ataxic gait and nystagmus, was noted, with subsequent progression of neurological manifestations. At the time of the observation, the proband had extensive regions of hypopigmented skin patches on the body and extremities, which have progressed over time. Whole-genome sequencing revealed compound heterozygous variants in the SUPV3L1 gene: c.272-2A>G and c.1924A>C; p.(Ser642Arg). RNA analysis demonstrated splicing changes attributable to the c.272-2A>G variant. ELISA assay showed increased Complex I content in the patient’s fibroblasts. This case underscores the phenotypic diversity associated with SUPV3L1 mutations, emphasizing the importance of considering mitochondrial RNA helicase dysfunction in the differential diagnosis of neurodegenerative disorders. Further elucidation of the molecular mechanisms underlying SUPV3L1-associated pathology may provide valuable insights into targeted therapeutic interventions. Full article

An intronic GAA repeat expansion in the FGF14 gene was recently identified as a common cause of autosomal dominant GAA-FGF14 ataxia (SCA27B). We aimed to characterize in detail the clinical and video-oculographic features in our cohort of SCA27B patients. We genotyped the FGF14 GAA repeat expansion in 52 patients with unsolved late-onset cerebellar ataxia. Brain MRI and nerve conduction study, as well as video-oculographic (VOG) assessment, were performed. Eight patients (15.4%) with pathogenic GAA repeat expansion in the FGF14 gene were found. The median age at onset was 51 years (range—23–63 years). Sensory axonal neuropathy was found in 5/8 patients. Cerebellar atrophy was observed in 5/8 patients, and in one case, pontocerebellar atrophy was found. All tested patients had impaired smooth pursuit, 5/6 patients had impaired vestibulo-ocular reflex suppression, nystagmus, and an increased number of square wave jerks, 4/6 patients had horizontal gaze-evoked nystagmus, 3/6 had spontaneous downbeat nystagmus, and 1/6 had an upbeat one. Video head impulse test gain was lower than 0.8 on both sides in 2/4 patients, along with the presence of overt saccades. Further studies in different cohorts are needed to complete the phenotype of the FGF14-related disorders. Full article

Objectives: Even though BPPV is one of the most common causes of vertigo, it is often underdiagnosed and omitted in the diagnosis of patients reporting vertigo. The aim of the study was to establish a diagnostic pattern useful in patients admitted due to vertigo, based on the most common clinical characteristics of patients suffered from posterior canal BPPV (PC-BPPV), horizontal canal BPPV with geotropic (HCG-BPPV) and apogeotropic nystagmus (HCA-BPPV). Methods: The analysis covered the results obtained in 105 patients with a positive result of the Dix-Hallpike maneuver or the supine roll test. The patients were divided into 3 groups based on the BPPV type: gr.1:PC-BPPV (60%); gr.2: HCG-BPPV (27%); gr.3: HCA-BPPV (13%). Patients before the diagnostic maneuvers filled the questionnaire concerning their symptoms and previous diseases. Results: Almost all patients had vertigo during turning over in bed and the character of the symptoms was paroxysmal. The answers to questions about the type of head movement evoked vertigo and how long vertigo lasted were differentiating. The percentages of correct diagnosis speculated by the combined answers were 69.6% in PC-BPPV, 61.8% in HCG-BPPV, and 80% in HCA-BPPV. Conclusions: Basing on those observations there is presented the diagnostic schedule which could be useful in dizziness examination. The above results indicate that a properly collected interview with the patient allows for a high percentage of accurate diagnosis. Full article

Nystagmus induced by applying an intense vibratory stimulus to the skull (SVIN) indicates vestibular functional asymmetry. In unilateral vestibular loss, a 100 Hz bone-conducted vibration given to either mastoid immediately causes a primarily horizontal nystagmus. The test is performed in darkness to avoid visual fixation (VF) but there are no data about how much VF affects the often-intense SVIN. The aim is to analyze the amount of reduction in SVIN when VF is allowed during testing. Thus, all patients seen in a tertiary hospital for vertigo or dizziness with positive SVIN were included. SVIN was recorded for 10 s for each condition: without VF (aSVINwo) and with VF (aSVINw). We obtained an aSVINwo and an aSVINw as average slow-phase velocities (SPV) without and with VF. VF index (FI_SVIN) was calculated as the ratio of SPV. Among the 124 patients included, spontaneous nystagmus (SN) was found in 25% and the median slow phase velocity (mSPV) (without VF) of SN was 2.6 ± 2.4°/s. Mean FI_SVIN was 0.27 ± 0.29. FI_SVIN was 0 in 42 patients, and FI_SVIN between 0 and 1 was found in 82 (mean FI_SVIN 0.39 ± 0.02). Fixation suppression was found in all patients with SVIN in cases of peripheral vestibulopathy. FI_SVIN clearly delineates two populations of patients: with or without a complete visual reduction in nystagmus. Full article

In this study, we propose a deep learning-based nystagmus detection algorithm using video oculography (VOG) data to diagnose benign paroxysmal positional vertigo (BPPV). Various deep learning architectures were utilized to develop and evaluate nystagmus detection models. Among the four deep learning architectures used in this study, the CNN1D model proposed as a nystagmus detection model demonstrated the best performance, exhibiting a sensitivity of 94.06 ± 0.78%, specificity of 86.39 ± 1.31%, precision of 91.34 ± 0.84%, accuracy of 91.02 ± 0.66%, and an F₁-score of 92.68 ± 0.55%. These results indicate the high accuracy and generalizability of the proposed nystagmus diagnosis algorithm. In conclusion, this study validates the practicality of deep learning in diagnosing BPPV and offers avenues for numerous potential applications of deep learning in the medical diagnostic sector. The findings of this research underscore its importance in enhancing diagnostic accuracy and efficiency in healthcare. Full article

Objective: Cochlear receptors are sensitive to vibratory stimuli. Based on this sensibility, bone-anchored hearing aids have been introduced to correct unilateral or bilateral conductive or mixed hearing loss and unilateral deafness. The vestibular system is also sensitive to the vibratory stimulus and this type of response is used in clinics to test its functionality. Being aware of this double separated sensibility, we wondered whether bone vibration, which activates the acoustic receptors of patients with bone conduction aids, can also influence the functionality of the vestibular system. Methods: To this end, we recruited 12 patients with a bone-anchored hearing aid and evaluated their vestibular function with and without an activated vibratory acoustic device. Results: Our results show that the vibratory stimulus delivered by the bone conduction aid also reaches and stimulates the vestibular receptors; this stimulation is evidenced by the appearance or modification of some nystagmus findings during bedside vestibular testing. Despite this, none of these patients complained of dizziness or vertigo during prosthesis use. Nystagmus that appeared or changed during acoustic vibratory stimulation through the prosthesis was almost all predominantly horizontal, unidirectional with respect to gaze or body position, inhibited by fixation, and most often consistent with vestibular function tests indicating peripheral vestibular damage. Conclusions: The findings of sound-evoked nystagmus seem to indicate peripheral rather than central vestibular activation. The occurrence of some predominantly horizontal and high-frequency induced nystagmus seems to attribute the response mainly to the utricle and lateral semicircular canal. Full article

GNB1 encephalopathy is a rare genetic disease caused by pathogenic variants in the G Protein Subunit Beta 1 (GNB1) gene, with only around 68 cases documented worldwide. Although most cases had been caused by de novo germline mutations, in this case, the pathogenic variant was inherited from patient’s mother, indicating an autosomal dominant inheritance pattern. The patient presented at 25 years of age with mild developmental delay and cognitive impairment, prominent generalized dystonia, and horizontal nystagmus which are all characterizing symptoms of GNB1 encephalopathy. Electroencephalography (EEG) showed no epileptiform patterns, and magnetic resonance imaging (MRI) revealed hypointensities in globus pallidus and dentate nucleus areas. The main theory for GNB1 encephalopathy pathogenesis is neuronal hyperexcitability caused by impaired ion channel regulation. Due to low specificity of symptoms, diagnosis relies on genetic testing. As there are no standardized GNB1 encephalopathy treatment guidelines, evaluation of different treatment options is based on anecdotal cases. Reviewing different treatment options, deep brain stimulation and intrathecal baclofen pump, as well as some other medications still in preclinical trials, seem to be the most promising. Full article

The third window syndrome, often associated with the Tullio phenomenon, is currently most often observed in patients with a superior semicircular-canal dehiscence (SCD) but is not specific to this pathology. Clinical and vestibular tests suggestive of this pathology are not always concomitantly observed and have been recently complemented by the skull-vibration-induced nystagmus test, which constitutes a bone-conducted Tullio phenomenon (BCTP). The aim of this work was to collect from the literature the insights given by this bedside test performed with bone-conducted stimulations in SCD. The PRISMA guidelines were used, and 10 publications were included and analyzed. Skull vibration-induced nystagmus (SVIN), as observed in 55 to 100% of SCD patients, usually signals SCD with greater sensitivity than the air-conducted Tullio phenomenon (ACTP) or the Hennebert sign. The SVIN direction when the test is performed on the vertex location at 100 Hz is most often ipsilaterally beating in 82% of cases for the horizontal and torsional components and down-beating for the vertical component. Vertex stimulations are more efficient than mastoid stimulations at 100 Hz but are equivalent at higher frequencies. SVIN efficiency may depend on stimulus location, order, and duration. In SCD, SVIN frequency sensitivity is extended toward high frequencies, with around 400 Hz being optimal. SVIN direction may depend in 25% on stimulus frequency and in 50% on stimulus location. Mastoid stimulations show frequently diverging results following the side of stimulation. An after-nystagmus observed in 25% of cases can be interpreted in light of recent physiological data showing two modes of activation: (1) cycle-by-cycle phase-locked activation of action potentials in SCC afferents with irregular resting discharge; (2) cupula deflection by fluid streaming caused by the travelling waves of fluid displacement initiated by sound or vibration at the point of the dehiscence. The SVIN direction and intensity may result from these two mechanisms’ competition. This instability explains the SVIN variability following stimulus location and frequency observed in some patients but also discrepancies between investigators. SVIN is a recent useful insight among other bedside examination tests for the diagnosis of SCD in clinical practice. Full article

Direction-changing positional nystagmus (DCPN), which refers to the change in the direction of nystagmus with different head positions, is a well-known characteristic of horizontal semicircular canal BPPV. The supine head roll test is commonly used to diagnose horizontal canal BPPV. However, persistent geotropic DCPN observed during this test cannot be explained by the conventional explanations of canalolithiasis or cupulolithiasis. To account for this unique nystagmus, the concept of a “light cupula” has been recently introduced. In this review, we provide an overview of the historical background, clinical features and diagnostic methods, proposed mechanisms, and treatment strategies associated with the light cupula phenomenon based on the available literature to date. Full article