Positional and positioning vertigo and nystagmus

Deep Eutectic Solvent-Based Highly Sensitive Turn-On Fluorescent Probe for D2O

Owing to the importance of heavy water in spectroscopy, nuclear energy generation, chemical characterization, and biological industry, a design of a robust, cheap, nontoxic, and sensitive D2O sensor is very important. In this work, taking advantage of the singular emission fluorescence of the deep eutectic solvent prepared in our laboratory, we propose a first of its kind highly sensitive turn-on fluorescent sensor to effectively sense D2O at an ultratrace level based on rapid exchange of the labile DES proton with deuterium. This method can be used as a full-range heavy water detection strategy with a limit of detection of 0.079% (v/v) or 870 ppm. The isotopic purity (IP) obtained from DES fluorescence measurements is also in close agreement with that of the conventional FT-IR method. The current DES-based sensor thus allows both sensing and isotopic purity of D2O and can serve as one of the most sensitive monitoring strategies for heavy water analysis.

Chiari I malformation management in patients with heritable connective tissue disorders

Background

Chiari malformation type I (CMI) is relatively common neurosurgical condition typically treated with posterior fossa decompression. However, the management of CMI in patients with heritable connective tissue disorders (CTDs), such as Ehlers-Danlos Syndrome, Marfan Syndrome, or Osteogenesis Imperfecta, involves a unique set of perioperative challenges.

Objective

This study aims to define the demographic information, comorbidities, and perioperative course of patients with concomitant CMI and CTD.

Methods

Patients with CMI admitted for surgical decompression from 2008 to 2015 were captured using the National Inpatient Sample (NIS). Information was collected based on ICD-9 codes. Descriptive and regression analyses were performed in SPSS (version 26).

Results

38,169 CMI patients, 353 of whom had CTD (0.92%), were identified. CMI patients with CTD were more likely to be female (p < 0.001) and present during teenage (p = 0.033) or young adult years (p < 0.001). They had more chronic issues (p < 0.001): systemic comorbidities include postural orthostatic tachycardia syndrome, cardiac dysrhythmias, and gastroparesis (all p < 0.001). CNS comorbidities include migraine, tethered spinal cord, and epilepsy (all p < 0.001). They have increased joint instability (both p < 0.001), as well as craniocervical instability (CCI). More posterior cervical fusion surgeries and application of cervical halo devices were seen during the same inpatient stay (both p < 0.001).

Conclusions

Patients with concurrent CTD and CMI were more likely to present with complex Chiari and associated CCI. They were also younger, more often female, and had more systemic, CNS, and joint abnormalities. As such, preoperative recognition of an underlying CTD is imperative to achieve optimal outcomes in this patient population.

De novo lipogenesis in non-alcoholic fatty liver disease: Quantification with stable isotope tracers

BACKGROUND

Non-alcoholic fatty liver disease (NAFLD) is characterized as an abnormal accumulation of triglyceride in hepatocytes. Hepatic de novo lipogenesis may play an important role in the accumulation of lipids in the liver during NAFLD. Due to the importance of lipid biosynthetic fluxes in NAFLD and T2D, tracer methodologies have been developed for their study and quantification. Here, we address novel approaches to measure and quantify DNL using stable isotope tracers. Deuterated water is a widely used tracer for quantifying DNL rates in both animal models and humans. Enrichment of lipid hydrogens from ² H2O can be resolved and quantified by ² H NMR and MS spectroscopy of isolated lipids. NMR provides a much higher level of positional enrichment information compared with MS which yields a more detailed picture of lipid biosynthetic. It can also be used to quantify low levels of lipid ¹³ C enrichment from a second tracer such as [U-¹³ C]sugar with minimal interference of one tracer with the other.

CONCLUSIONS

Despite the clear association between elevated DNL activity and increased hepatic triglyceride levels, implementation of non-destructive and novel methods to quantify DNL and its contribution to NAFLD are also of huge interest.

Prolonged Positional Downbeat Nystagmus in Benign Paroxysmal Positional Vertigo: A Case Report and Literature Review

Purpose This study aimed to report an unusual case of benign paroxysmal positional vertigo (BPPV), who showed prolonged positional downbeat nystagmus without latency and was diagnosed with cupulolithiasis of the anterior canal (AC). We compared this case with one of typical AC-BPPV, and possible mechanisms underlying the atypical characteristics were discussed. Method Two patients diagnosed with AC-BPPV were reported. Positional testing using video-oculography goggles was performed, and outcomes were measured via medical records and analysis of videos of the nystagmus. Results Downbeat nystagmus was observed in the contralateral Dix-Hallpike test in both cases. The torsional component was subtle or absent, but motion was induced toward the affected ear. The two cases differed in latency and duration of vertigo, as well as habituation. The patient with atypical nystagmus showed little or no latency and longer duration. Moreover, there was no habituation on repeated tests. The nystagmus showed several differences from that of typical AC-BPPV. Conclusions Based on our case, AC-BPPV may induce various unusual clinical manifestations of nystagmus. Accurate diagnosis requires careful consideration of the patient's symptoms and the characteristics of the nystagmus. Supplemental Material https://doi.org/10.23641/asha.14265356.

Which Inner Ear Disorders Lie Behind a Selective Posterior Semicircular Canal Hypofunction on Video Head Impulse Test?

OBJECTIVE

To assess all different patterns of associated abnormalities on audiometry, bithermal caloric test (BCT) and cervical/ocular vestibular-evoked myogenic potentials (VEMPs) to air/bone-conduction in patients with selective posterior semicircular canal (PSC) hypofunction and to correlate them with underlying disorders.

STUDY DESIGN

Retrospective review.

SETTING

Tertiary referral center.

PATIENTS

51 patients (23 men, 28 women, mean age 57.5 yr) with isolated PSC deficit (one bilateral).

INTERVENTIONS

Correlation with instrumental data and underlying diagnoses.

MAIN OUTCOME MEASURES

Video-oculographic findings, objective measurements on audiometry, BCT, VEMPs and video-head impulse test (vHIT).

RESULTS

Ongoing or previous acute vestibular loss (AVL) was diagnosed in 13 patients (25.5%, 3 inferior vestibular neuritis, 10 AVL with sudden sensorineural hearing loss [SSNHL]), Meniere's disease (MD) in 12 (23.5%), cerebellopontine angle (CPA) lesion in 9 (17.6%), various causes in 7 (13.7%), benign paroxysmal positional vertigo (BPPV) involving the non-ampullary arm of PSC in 5 cases (9.8%) whereas unknown pathology in 5 (9.8%). Involvement of at least one additional receptor besides PSC was seen in 89.8% of cases. Cochlear involvement was diagnosed in 74.5% with pure-tone average significantly greater in patients with AVL+SSNHL (p < 0.05). Overall involvement of labyrinthine receptors or afferents was highest in patients with AVL+SSNHL (p < 0.01), MD and CPA lesions (p < 0.05).

CONCLUSIONS

Isolated loss of PSC function on vHIT is mostly accompanied by additional labyrinthine deficits that could only be identified through an accurate instrumental evaluation. Assessment of all receptors and afferents should be always pursued to identify the lesion site and better understand the underlying pathophysiological mechanisms.

Clinical and VNG Features in Anterior Canal BPPV-An Analysis of 13 Cases

Objective: To define diagnostic VNG features in anterior canal BPPV during positional testing (Dix-Hallpike, supine head hanging, and McClure Pagnini tests).

Study Design: A retrospective study of patients diagnosed with anterior canal BPPV across four referral centers in New Delhi, Kochi, Bangalore, and Dubai.

Subjects and Methods: Clinical records of 13 patients with AC BPPV out of 1,350 cases, during a 3-years period, were reviewed and analyzed by four specialists.

Results: Four patients had positional down beating nystagmus with symptoms of vertigo during the bilateral DHP maneuver. Seven cases had positional down beating nystagmus only on one side of DHP. Typical down beating nystagmus was seen in 10 out of 13 cases during the straight head hanging maneuver. Down beating torsional nystagmus was seen in 6 out of 13 cases. Down beating with horizontal nystagmus was seen in three cases (in DHP and MCP mainly) while pure down beating nystagmus during SHH was only seen in four cases.

Conclusion: We conclude that anterior canal BPPV is a rare but definite entity. It may not be apparent on positional testing the first time, so repeated testing may be needed. The most consistent diagnostic maneuver is SHH though there were patients in which findings could only be elicited using DHP testing. We recommend a testing protocol that includes DHP testing on both sides and SHH. MCP testing may also evoke DBN with or without the torsional component. Reversal of nystagmus on reversal of testing position is unusual but can occur. The Yacovino maneuver is effective in resolving AC BPPV. We also propose a hypothesis that explains why DHP testing is sensitive to AC BPPV on either side, whereas MCP lateral position on one side is only sensitive to AC BPPV on one side. We have explained a possible role for the McClure Pagnini test in side determination and therapeutic implications.

Central positional nystagmus in inferior cerebellar peduncle lesions: a case series

We aimed to characterize the central positional nystagmus (CPN) observed in lesions involving the inferior cerebellar peduncle (ICP). We analyzed the clinical and neurotologic findings in six patients with an isolated unilateral ICP infarction that had been diagnosed at a university hospital in South Korea from 2003 to 2019. Patients usually presented with acute vestibular syndrome in isolation (4/6, 67%). Ipsilesional spontaneous nystagmus was observed in five while supine (5/6, 83%). Four (4/6, 67%) patients showed CPN which included apogeotropic (n = 3) or geotropic (n = 1) during head turning to either side while supine, and vertical nystagmus during straight-head hanging, Dix-Hallpike maneuvers, or up-righting (n = 3). Four patients showed contraversive ocular tilt reaction or tilt of the subjective visual vertical. Bedside and video head-impulse tests were normal in all patients. CPN is a usual finding in ICP lesions, and may be ascribed to damage of the fibers running from the nodulus/uvula onto the vestibular nucleus via the ICP.

Pseudo-spontaneous nystagmus in lateral semicircular canal benign paroxysmal positional vertigo: Correlation with bow and lean test in a pitch plane

Objectives

We investigated the incidence and characteristics of pseudo-spontaneous nystagmus (PSN) in benign paroxysmal positional vertigo involving the lateral semicircular canal (LC-BPPV) and evaluated the correlation between PSN and the bow and lean test.

Methods

We examined nystagmus in the sitting position using video-oculography goggles in 131 LC-BPPV patients. The positioning test and bow and lean test were also performed. Patients were divided into canalolithiasis and cupulolithiasis groups according to the character of nystagmus. In each group, the incidence and direction of PSN, correlation with the bow and lean test, and treatment outcome were analyzed.

Results

PSN was observed in 25 cases (19.1%) in LC-BPPV patients, 7 of which were canalolithiasis and 18 of which were cupulolithiasis (p = 0.098). Of the 25 patients with PSN, 21 (84%) exhibited nystagmus consistent with the lean test whereas 4 (16%) exhibited nystagmus consistent with the bow test. In patients with PSN, nystagmus was observed in the bow and lean test in all cases (23/23), but in patients without PSN, no nystagmus was observed in 13 cases (13/87) in the bow and lean test (p = 0.048). The number of barbecue maneuvers performed until the end of treatment was 1.4 ± 0.7 in patients with PSN and 1.4 ± 0.9 in those without PSN (p = 0.976).

Conclusion

We identified PSN in patients with LC-BPPV irrelevant of subtype. Moreover, all patients with PSN showed nystagmus in the bow and lean test. The direction of PSN was mostly consistent with that of the lean test (21/25, 84%). The presence of PSN was not related to the treatment outcome in this study.

Clinical Characteristics of Patients With Benign Paroxysmal Positional Vertigo Diagnosed Based on the Diagnostic Criteria of the Bárány Society

Objectives: To analyze the clinical characteristics of patients with benign paroxysmal positional vertigo (BPPV) diagnosed based on the diagnostic criteria of Bárány Society, verify the clinical application value of the diagnostic criteria, and further explore the clinical problems associated with the diagnosis of possible BPPV.

Methods: A total of 481 patients with BPPV who were admitted from March 2016 to February 2019 were included. All patients were diagnosed by the Dix-Hallpike, straight head hanging and supine roll tests, the nystagmus was recorded using videonystagmography. For patients with possible BPPV (uncertain diagnosis), particle repositioning therapy and follow-up diagnosis were used to further clarify diagnosis.

Results: Based on Bárány Society's diagnostic criteria for BPPV, the distribution characteristics of different BPPV types were as follows: 159 (33.1%) patients had posterior canal BPPV-canalolithiasis (PC-BPPV-ca), 70 (14.6%) patients had horizontal canal BPPV-ca (HC-BPPV-ca), 55 (11.4%) patients had spontaneously resolved-probable-BPPV (Pro-BPPV), and 53 (11.0%) patients had HC-BPPV-cupulolithiasis (HC-BPPV-cu). In emerging and controversial BPPV, 51 (10.6%) patients had multiple canal BPPV (MC-BPPV), 30 (6.2%) patients had PC-BPPV-cu, and 19 (4.0%) patients had anterior canal BPPV-ca (AC-BPPV-ca), 44 (9.1%) patients had possible-BPPV (Pos-BPPV). Among the 44 patients with Pos-BPPV, 23 patients showed dizziness/vertigo without nystagmus during the initial positional test, five patients were possible MC-BPPV, four patients had persistent geotropic positional nystagmus lasting > 1 min when lying on both sides, and were considered to have Pos-HC-BPPV, four patients showed apogeotropic nystagmus when lying on one side, and were considered to have possible short-arm HC-BPPV, four patients showed geotropic nystagmus when lying on one side, and were considered to have Pos-HC-BPPV, three patients had down-beating nystagmus, lasing > 1 min, were considered to have Pos-AC-BPPV-cu. One patient showed transient apogeotropic positional nystagmus on both sides during the supine roll test, and was diagnosed with possible anterior arm HC-BPPV.

Conclusions: PC-BPPV-ca is the most common among patients with BPPV, followed by HC-BPPV-ca. In emerging and controversial BPPV, MC-BPPV, and Pos-BPPV were more common. For the diagnosis of Pos-BPPV, a combination of the history of typical BPPV, particle repositioning therapy and follow-up outcome is helpful to clarify the diagnosis.

Classification of vestibular signs and examination techniques: Nystagmus and nystagmus-like movements

This paper presents a classification and definitions for types of nystagmus and other oscillatory eye movements relevant to evaluation of patients with vestibular and neurological disorders, formulated by the Classification Committee of the Bárány Society, to facilitate identification and communication for research and clinical care. Terminology surrounding the numerous attributes and influencing factors necessary to characterize nystagmus are outlined and defined. The classification first organizes the complex nomenclature of nystagmus around phenomenology, while also considering knowledge of anatomy, pathophysiology, and etiology. Nystagmus is distinguished from various other nystagmus-like movements including saccadic intrusions and oscillations.

View accompanying videos at http://www.jvr-web.org/ICVD.html

Approach to the Examination and Classification of Nystagmus

BACKGROUND AND PURPOSE

Physical therapists caring for patients with neurologic or vestibular disorders must routinely examine and characterize nystagmus and other oscillatory eye movements. Often, the diagnosis hinges on proper interpretation of the nystagmus pattern. This requires understanding the terminology surrounding the numerous attributes and influencing factors of nystagmus, a systematic approach to the examination, and a classification structure that guides practitioners to the specific nystagmus type and subsequent evaluation and management.

SUMMARY OF KEY POINTS

Nystagmus is an involuntary, rapid, rhythmic, oscillatory eye movement with at least 1 slow phase. Jerk nystagmus has a slow phase and a fast phase. Pendular nystagmus has only slow phases. Nystagmus is distinguished from other types of oscillatory eye movements, such as saccadic intrusions or oscillations. Characterizing nystagmus requires clearly describing its trajectory. This includes choosing a reference frame to describe the axes or planes and direction of eye movements. Several attributes are used to describe nystagmus: binocularity, conjugacy, velocity, waveform, frequency, amplitude, intensity, temporal profile, and age at first appearance. Several factors may influence nystagmus, including gaze position, visual fixation, vergence, and a variety of provocative maneuvers. Classification of nystagmus may be organized by physiologic or pathologic nystagmus versus other nystagmus-like movements. Pathologic nystagmus may be spontaneous, gaze-evoked, or triggered by provocative maneuvers. The combination of attributes allows differentiation between the many peripheral and central forms.

RECOMMENDATIONS FOR CLINICAL PRACTICE

Therapists should carefully examine and characterize the trajectory and other attributes and influencing factors of nystagmus to accurately classify it and arrive at the correct diagnosis.

Risk Factors for Positional Vertigo and the Impact of Vertigo on Daily Life: The Korean National Health and Nutrition Examination Survey

Background and Objectives

This study aimed to analyze risk factors for positional vertigo (PV) and the influence thereof on daily life and subjective quality-of-life (QoL).

Subject andMethods

A cross-sectional study was conducted using data of the 2010 Korea National Health and Nutrition Examination Survey. The study population consisted of 1,274 individuals aged >40 years for whom complete dizziness-related data were available. Blood and urine tests were performed, and nutritional intake, QoL, and subjective health status were measured using a questionnaire. The associations between PV and blood/urine test data and nutritional intake were evaluated via multiple logistic regression analysis.

Results

A history of PV within the previous year was reported by 98 individuals (7.7%). Advanced age and female gender were both significantly associated with such a history. Serum hemoglobin, creatinine, and triglyceride levels correlated significantly with a history of PV. Carotene, vitamin A, and vitamin B2 intakes were significantly lower in individuals with PV. Multivariate analysis revealed that only age was significantly associated with a history of PV (p=0.003). Although subjective health status score was not significantly lower in subjects with PV, subjective impairments in mobility, self-care, the performance of usual activities, and anxiety/depression were more prominent in individuals with PV. A fall history and limitations of activity were also significantly higher in individuals with PV (p<0.001 and p=0.003, respectively).

Conclusions

Age was a risk factor for PV, which affected most QoL parameters, fall frequency, and the performance of normal activities.

Analyses with the Video Head Impulse Test During the Canalith Repositioning Maneuver in Patients with Isolated Posterior Semicircular Canal Benign Paroxysmal Positional Vertigo

Objective

To evaluate the posterior semicircular canal (PSCC) functions using video head impulse test (vHIT) during canalith repositioning maneuver (CRM) treatment in patients with isolated, posterior semicircular canal benign paroxysmal positional vertigo (PSCC-BPPV).

Methods

A total of 44 subjects comprising of 24 subjects with isolated PSCC-BPPV and 20 age- and sex-matched healthy control subjects were enrolled in the present study. vHIT was performed for the affected PSCC before and just after CRM and at the third and seventh day and first month to evaluate vestibulo-ocular reflex (VOR) gain, gain asymmetry (GA), and corrective saccades. Repeated determinations of VOR gain and GA were compared to evaluate the time course of vHIT measurements during CRM treatment in isolated PSCC-BPPV patients, and the values were also compared with the control group.

Results

VOR gains and GA values were not statistically different before and after CRM and at the third-day, seventh-day and first-month visits for the affected PSCC. Moreover, values did not differ between the BPPV and control groups, and none of the subjects demonstrated corrective saccades.

Conclusion

To our knowledge, this study is the first report to investigate vHIT measurements with a time course of alterations during CRM treatment in PSCC-BPPV patients. vHIT may not provide an additional contribution for evaluating vestibular dysfunction during the diagnosis and treatment of isolated PSCC-BPPV.

Incidence and Clinical Significance of Positional Downbeat Nystagmus in Posterior Canal Benign Paroxysmal Positional Vertigo

Background and Purpose

The aim of this study was to determine the incidence and clinical significance of positional downbeat nystagmus (pDBN) after treatment of posterior canal (PC) benign paroxysmal positional vertigo (BPPV).

Methods

We recruited 77 patients with a diagnosis of PC BPPV, and assessed the presence of pDBN during follow-up positional tests after performing the Epley maneuver.

Results

An immediate response to the Epley maneuver was exhibited by 57 of the 77 patients, with resolution of their positional torsional upbeat nystagmus (pT-UBN). Twenty-two (39%) of them exhibited pDBN during follow-up tests performed 1 hour later. The latency and duration of pDBN were 3.2±2.0 and 12.0±10.0 s (mean±SD), respectively. The maximum slowphase velocity of pDBN was 5.1±2.5 degrees, and ranged from 2.0 to 12.2 degrees. A torsional component was also observed in six patients. The patients with pDBN were much more likely to develop a typical form of PC BPPV again at a 1-week follow-up (5/22, 23%) compared to those without pDBN (1/31, 3%; p=0.036). pDBN disappeared in all patients within 6 months.

Conclusions

Our study found transient pDBN in 40% of patients with PC BPPV after the immediate resolution of positional vertigo and pT-UBN. pDBN may be attributed to residual debris in the distal portion of the PC, which can move toward the ampulla producing an ampullopetal flow of endolymph during positioning.

Dizziness and vertigo syndromes viewed with a historical eye

Seasickness, fear of heights, and adverse effects of alcohol were the major areas where descriptions of vertigo and dizziness were found in Roman, Greek, and Chinese texts from about 730 BC-600 AD. A few detailed accounts were suggestive of specific vestibular disorders such as Menière's attacks (Huangdi Neijing, the Yellow Thearch's Classic of Internal Medicine) or vestibular migraine (Aretaeus of Cappadocia). Further, the etymological and metaphorical meanings of the terms and their symptoms provide fascinating historical insights, e.g. Vespasian's feelings of dizzy exultations when becoming Emperor (69 AD) after Nero's suicide or the figurative meaning of German "Schwindel" (vertigo) derived from English "swindle" to express "financial fraud" in the Eighteenth century. The growth of knowledge of the vestibular system and its functions began primarily in the Nineteenth century. Erasmus Darwin, however, was ahead of his times. His work Zoonomia, or The Laws of Organic Life in 1794 described new dizziness syndromes and concepts of sensorimotor control including the mechanism of fear of heights as well as made early observations on positional alcohol vertigo. The latter is beautifully illustrated by the German poet and cartoonist Wilhelm Busch (1832-1908) who also documented the alleviating effect of the "morning after drink". The mechanism underlying positional alcohol vertigo, i.e., the differential gravities of alcohol and endolymph, was discovered later in the Nineteenth century. The first textbook on neurology (Lehrbuch der Nervenkrankheiten des Menschen, 1840) by Moritz Romberg contained general descriptions of signs and symptoms of various conditions having the key symptom of vertigo, but no definition of vestibular disorders. Our current knowledge of vestibular function and disorders dates back to the seminal work of a group of Nineteenth century scientists, e.g., Jan Evangelista Purkinje, Ernst Mach, Josef Breuer, Hermann Helmholtz, and Alexander Crum-Brown.

Benign paroxysmal positional vertigo: Diagnostic criteria Consensus document of the Committee for the Classification of Vestibular Disorders of the Bárány Society

This article presents operational diagnostic criteria for benign paroxysmal positional vertigo (BPPV), formulated by the Committee for Classification of Vestibular Disorders of the Bárány Society. The classification reflects current knowledge of clinical aspects and pathomechanisms of BPPV and includes both established and emerging syndromes of BPPV. It is anticipated that growing understanding of the disease will lead to further development of this classification.

Isolated transient vertigo: posterior circulation ischemia or benign origin?

Background

Isolated transient vertigo can be the only symptom of posterior circulation ischemia. Thus, it is important to differentiate isolated vertigo of a cerebrovascular origin from that of more benign origins, as patients with cerebral ischemia have a much higher risk for future stroke than do those with ‘peripheral’ vertigo. The current study aims to identify risk factors for cerebrovascular origin of isolated transient vertigo, and for future cerebrovascular events.

Methods

From the files of 339 outpatients with isolated transient vertigo we extracted history, clinical and technical findings, diagnosis, and follow-up information on subsequent stroke or transient ischemic attack (TIA). Risk factors were analyzed using multivariate regression models (logistic or Cox) and reconfirmed in univariate analyses.

Results

On first presentation, 48 (14.2%) patients received the diagnosis ‘probable or definite cerebrovascular vertigo’. During follow-up, 41 patients suffered stroke or TIA (event rate 7.9 per 100 person years, 95% confidence interval (CI) 5.5–10.4), 26 in the posterior circulation (event rate 4.8 per 100 person years, 95% CI 3.0–6.7). The diagnosis was not associated with follow-up cerebrovascular events. In multivariate models testing multiple potential determinants, only the presentation mode was consistently associated with the diagnosis and stroke risk: patients who presented because of vertigo (rather than reporting vertigo when they presented for other reasons) had a significantly higher risk for future stroke or TIA (p = 0.028, event rate 13.4 vs. 5.4 per 100 person years) and for future posterior circulation stroke or TIA (p = 0.044, event rate 7.8 vs. 3.5 per 100 person years).

Conclusions

We here report for the first time follow-up stroke rates in patients with transient isolated vertigo. In such patients, the identification of those with cerebrovascular origin remains difficult, and presentation mode was found to be the only consistent risk factor. Confirmation in an independent prospective sample is needed.

Decreased postural control in adult survivors of childhood cancer treated with chemotherapy

The objective of cancer treatment is to secure survival. However, as chemotherapeutic agents can affect the central and peripheral nervous systems, patients must undergo a process of central compensation. We explored the effectiveness of this compensation process by measuring postural behaviour in adult survivors of childhood cancer treated with chemotherapy (CTS). We recruited sixteen adults treated with chemotherapy in childhood for malignant solid (non-CNS) tumours and 25 healthy age-matched controls. Subjects performed posturography with eyes open and closed during quiet and perturbed standing. Repeated balance perturbations through calf vibrations were used to study postural adaptation. Subjects were stratified into two groups (treatment before or from 12 years of age) to determine age at treatment effects. Both quiet (p = 0.040) and perturbed standing (p ≤ 0.009) were significantly poorer in CTS compared to controls, particularly with eyes open and among those treated younger. Moreover, CTS had reduced levels of adaptation compared to controls, both with eyes closed and open. Hence, adults treated with chemotherapy for childhood cancer may suffer late effects of poorer postural control manifested as reduced contribution of vision and as reduced adaptation skills. These findings advocate development of chemotherapeutic agents that cause fewer long-term side effects when used for treating children.

Clinical assessment of hepatic de novo lipogenesis in non-alcoholic fatty liver disease

Non-alcoholic fatty liver disease (NAFLD) is heralded as the next big global epidemic. Hepatic de novo lipogenesis (DNL), the synthesis of new fatty acids from non-lipid sources, is thought to play a pivotal role in the development of NAFLD. While there is currently no NAFLD-specific therapeutic agent available, pharmaceutical drugs aimed at reducing hepatic fat accretion may prove to be a powerful ally in the treatment and management of this disease. With a focus on NAFLD, the present review summarizes current techniques examining DNL from a clinical perspective, and describes the merits and limitations of three commonly used assays; stable-label isotope tracer studies, fatty acid indexes and indirect calorimetry as non-invasive measures of hepatic DNL. Finally, the application of DNL assessments in the pharmacological and nutraceutical treatment of NAFLD/NASH is summarized. In a clinical research setting, measures of DNL are an important marker in the development of anti-NAFLD treatments.

Persistent Down-Beating Torsional Positional Nystagmus: Posterior Semicircular Canal Light Cupula?

A 16-year-old boy with rotatory positional vertigo and nausea, particularly when lying down, visited our clinic. Initially, we observed vertical/torsional (downward/leftward) nystagmus in the supine position, and it did not diminish. In the sitting position, nystagmus was not provoked. Neurological examinations were normal. We speculated that persistent torsional down-beating nystagmus was caused by the light cupula of the posterior semicircular canal. This case provides novel insights into the light cupula pathophysiology.

Consensus Paper: Revisiting the Symptoms and Signs of Cerebellar Syndrome

The cerebellum is involved in sensorimotor operations, cognitive tasks and affective processes. Here, we revisit the concept of the cerebellar syndrome in the light of recent advances in our understanding of cerebellar operations. The key symptoms and signs of cerebellar dysfunction, often grouped under the generic term of ataxia, are discussed. Vertigo, dizziness, and imbalance are associated with lesions of the vestibulo-cerebellar, vestibulo-spinal, or cerebellar ocular motor systems. The cerebellum plays a major role in the online to long-term control of eye movements (control of calibration, reduction of eye instability, maintenance of ocular alignment). Ocular instability, nystagmus, saccadic intrusions, impaired smooth pursuit, impaired vestibulo-ocular reflex (VOR), and ocular misalignment are at the core of oculomotor cerebellar deficits. As a motor speech disorder, ataxic dysarthria is highly suggestive of cerebellar pathology. Regarding motor control of limbs, hypotonia, a- or dysdiadochokinesia, dysmetria, grasping deficits and various tremor phenomenologies are observed in cerebellar disorders to varying degrees. There is clear evidence that the cerebellum participates in force perception and proprioceptive sense during active movements. Gait is staggering with a wide base, and tandem gait is very often impaired in cerebellar disorders. In terms of cognitive and affective operations, impairments are found in executive functions, visual-spatial processing, linguistic function, and affective regulation (Schmahmann's syndrome). Nonmotor linguistic deficits including disruption of articulatory and graphomotor planning, language dynamics, verbal fluency, phonological, and semantic word retrieval, expressive and receptive syntax, and various aspects of reading and writing may be impaired after cerebellar damage. The cerebellum is organized into (a) a primary sensorimotor region in the anterior lobe and adjacent part of lobule VI, (b) a second sensorimotor region in lobule VIII, and (c) cognitive and limbic regions located in the posterior lobe (lobule VI, lobule VIIA which includes crus I and crus II, and lobule VIIB). The limbic cerebellum is mainly represented in the posterior vermis. The cortico-ponto-cerebellar and cerebello-thalamo-cortical loops establish close functional connections between the cerebellum and the supratentorial motor, paralimbic and association cortices, and cerebellar symptoms are associated with a disruption of these loops.

Diagnostic, Pathophysiologic, and Therapeutic Aspects of Benign Paroxysmal Positional Vertigo

Benign paroxysmal positional vertigo is the most common peripheral vestibular disorder. It can be defined as transient vertigo induced by a rapid head position change, associated with a characteristic paroxysmal positional nystagmus. Canalolithiasis of the posterior semicircular canal is considered the most convincing theory of its pathogenesis and the development of appropriate therapeutic maneuvers resulted in its effective treatment. However, involvement of the horizontal or the anterior canal has been found in a significant rate and the recognition and treatment of these variants completed the clinical picture of the disease. This paper describes the advances in understanding how this disease is generated and discusses the current therapeutic modalities.

Isolated horizontal positional nystagmus from a posterior fossa lesion

Isolated vertigo with horizontal positional nystagmus as an impending sign of a central lesion has rarely been reported. Here we present neuro-otologic findings of patients with these clinical signs. Lesion overlays from 6 patients with ageotropic positional nystagmus revealed that the nodulus and vermis are common areas of injury. In contrast, 2 patients with geotropic positional nystagmus had cerebellar peduncle and lateral medullary lesions. These clinical findings suggest that vertigo with horizontal positional nystagmus, even in the absence of other initial neurological signs, may indicate a posterior fossa lesion, including that in the nodulus, vermis, and deep cerebellar structures.

Recognition and management of BPPV for an elderly female patient referred for low back pain: a resident's case study

Benign paroxysmal positional vertigo (BPPV) is common among older adults and frequently misdiagnosed or unidentified. Undiagnosed BPPV has been associated with depression, falls and ADL limitations. This case study describes the diagnostic process and management of BPPV for a 65-year-old patient with a primary complaint of chronic low back pain (LBP) in an outpatient orthopedic physical therapy setting. Following routine screening performed on initial evaluation, the patient was educated about examination findings that indicated the potential for BPPV and given the option to proceed with further assessment or defer until LBP was under control. The patient attended 16 visits over the course of care and the complaint of vertigo, described as a true spinning sensation, was assessed further on the visit 5. Continued assessment confirmed BPPV and the canalith repositioning procedure was administered. Following positive response to this intervention, the maneuver was re-administered on visit 6. Complete resolution of symptoms was reported on visit 7 and for the remainder of physical therapy services over the following month. Physical therapists may play a vital role in reducing healthcare expenses associated with cost to arrive at the diagnosis of BPPV, as well as improving the quality of life and safety of the older adult population affected by BPPV.

Symptomatic treatment and management of multiple sclerosis

The range of symptoms which occur in multiple sclerosis (MS) can have disabling functional consequences for patients and lead to significant reductions in their quality of life. MS symptoms can also interact with each other, making their management challenging. Clinical trials aimed at identifying symptomatic therapies have generally been poorly designed and have tended to be underpowered. Therefore, the evidence base for the management of MS symptoms with pharmacologic therapies is not strong and tends to rely upon open-label studies, case reports, and clinical trials with small numbers of patients and poorly validated clinical outcome measures. Recently, there has been a growing interest in the management of MS symptoms with pharmacologic treatments, and better-designed, randomized, double-blind, controlled trials have been reported. This chapter will describe the evidence base predominantly behind the various pharmacologic approaches to the management of MS symptoms, which in most, if not all, cases, requires multidisciplinary input. Drugs routinely recommended for individual symptoms and new therapies, which are currently in the development pipeline, will be reviewed. More interventional therapies related to symptoms that are refractory to pharmacotherapy will also be discussed, where relevant.

Natural course of positional down-beating nystagmus of peripheral origin

The aim of this study was to assess the natural course of positional down-beating nystagmus (pDBN) and vertigo in patients with no evidence of central nervous system involvement and of presumed peripheral origin. Fifty-three patients with pDBN had a complete otoneurological examination. All subjects, apart from three (excluded from the study), showed no additional neurological signs and normal brain imaging. Patients were randomly assigned to two groups: with or without treatment with exercise. Patients were seen again after 24 h, and then weekly for up to 6 months. Forty-seven patients (94%) showed pDBN in the straight head-hanging position and in a Dix-Hallpike position. A torsional component was detected in 17 patients (34%). The mean latency and duration of pDBN was 4.7 ± 5 s and 40.1 ± 22 s, respectively. After 2 weeks, only 12 patients (24%) still had pDBN and all but one patient had recovered by 1 month. Twenty patients (40%) were diagnosed with a typical posterior canal benign paroxysmal positional vertigo (PC BPPV) before or after pDBN. This study assessed for the first time the natural course of presumed peripheral pDBN, which was characterized by a spontaneous remission in 24 patients in the first week and in 49 patients within 4 weeks. pDBN is much more common than previously suggested, with about the same frequency as lateral canal BPPV. Furthermore, the clinical characteristics of pDBN have been highlighted, as well as its possible relationship to PC BPPV.

Quantitating lymphocyte homeostasis in vivo in humans using stable isotope tracers

Humans have a remarkable ability to maintain relatively constant lymphocyte numbers across many decades, from puberty to old-age, despite a multitude of infectious and other challenges and a dramatic decline in thymic output. This phenomenon, lymphocyte homeostasis, is achieved by matching the production, death, and phenotype transition rates across a network of varied lymphocyte subpopulations. Understanding this process in humans depends on the ability to measure in vivo rates of lymphocyte production and loss. Such investigations have been greatly facilitated by the advent of stable isotope labeling approaches, which use the rate of incorporation of a tracer into cellular DNA as a marker of cell division. Two labeling approaches are commonly employed, one using deuterium-labeled glucose and the other using deuterium-labeled water, also known as heavy water ((2)H(2)O). Here we describe the application of these two labeling techniques for measurement of human in vivo lymphocyte kinetics through the four phases of investigation: labeling, -sampling, analysis, and interpretation.

Posterior semicircular canal benign paroxysmal positional vertigo presenting with torsional downbeating nystagmus: an apogeotropic variant

The aim of this study is to verify the hypothesis that free-floating particles could sometimes localize into the distal portion of the non ampullary arm of the posterior semicircular canal (PSC) so that assuming the Dix-Hallpike's positions, the clot could move towards the ampulla eliciting a inhibitory torsional-down beating paroxysmal positional nystagmus (PPNy), instead of typical excitatory torsional-up beating PPNy. Among 45 patients with vestibular signs suggesting anterior semicircular canal paroxysmal positional vertigo (PPV), collected from February 2003 to August 2006, we detected a group of 6 subjects whose clinical findings showed a singular behaviour during follow-up. At the first check-up, all patients were submitted to different types of physical manoeuvres for ASC canalolithiasis. Patients were controlled during the same session and after one week. When we found that nystagmus was qualitatively changed we adopted the appropriate physical therapies for that sign. At a next check-up, after having performed some physical therapies, all patients had a typical PSC PPNy of the opposite side, with respect to that of the ASC initially diagnosed. Basing on these observations we conclude that PSC PPV, similarly to lateral semicircular canal PPV, could manifests in a apogeotropic variant.

Study II: mechanoreceptive sensation is of increased importance for human postural control under alcohol intoxication

Standing postural stability relies on input from visual, vestibular, proprioceptive and mechanoreceptive sensors. When the information from any of these sensors is unavailable or disrupted, the central nervous system maintains postural stability by relying more on the contribution from the reliable sensors, termed sensory re-weighting. Alcohol intoxication is known to affect the integrity of the vestibular and visual systems. The aim was to assess how mechanoreceptive sensory information contributed to postural stability at 0.00% (i.e. sober), 0.06% and 0.10% blood alcohol concentration (BAC) in 25 healthy subjects (mean age 25.1 years). The subjects were assessed with eyes closed and eyes open under quiet standing and while standing was perturbed by repeated, random-length, vibratory stimulation of the calf muscles. Plantar cutaneous mechanoreceptive sensation was assessed for both receptor types: slowly adapting (tactile sensitivity) and rapidly adapting (vibration perception). The correlation between recorded torque variance and the sensation from both mechanoreceptor types was calculated. The recorded stability during alcohol intoxication was significantly influenced by both the tactile sensation and vibration perception of the subjects. Moreover, the study revealed a fluctuating association between the subjects' vibration perception and torque variance during balance perturbations, which was significantly influenced by the level of alcohol intoxication, vision and adaptation. Hence, one's ability to handle balance perturbations under the influence of alcohol is strongly dependent on accurate mechanoreceptive sensation and efficient sensory re-weighting.

Benign paroxysmal positional vertigo: is vestibular evoked myogenic potential testing useful?

CONCLUSIONS

In benign paroxysmal positional vertigo (BPPV), vestibular evoked myogenic potentials (VEMPs) help to better define the extent of saccular damage and the patient's prognosis.

OBJECTIVES

To report the results of VEMPs in patients affected by BPPV of the posterior semicircular canal (PSC) in order to evaluate the presence of signs of saccular dysfunction compared to the normal population and to correlate them with the clinical picture.

METHODS

This was a prospective study in a tertiary referral center; 23 patients affected by BPPV of the PSC and 24 controls were evaluated. All patients underwent complete clinical history and otoneurologic and audiovestibular evaluation consisting of pure-tone audiometry, caloric testing, and registration of VEMPs.

RESULTS

VEMP thresholds and latencies were not different between patients and controls. As a group BPPV patients presented significantly higher abnormal VEMPs compared with controls (p < 0.001). Age positively correlated with VEMP threshold in the affected ear of patients and in controls; the number of BPPV attacks positively correlated with threshold and negatively with amplitude of VEMPs in the affected ear; duration of the last attack was negatively correlated with the effect of the maneuver performed.

Diagnosis of Single- or Multiple-Canal Benign Paroxysmal Positional Vertigo according to the Type of Nystagmus

Benign paroxysmal positional vertigo (BPPV) is a common peripheral vestibular disorder encountered in primary care and specialist otolaryngology and neurology clinics. It is associated with a characteristic paroxysmal positional nystagmus, which can be elicited with specific diagnostic positional maneuvers, such as the Dix-Hallpike test and the supine roll test. Current clinical research focused on diagnosing and treating various types of BPPV, according to the semicircular canal involved and according to the implicated pathogenetic mechanism. Cases of multiple-canal BPPV have been specifically investigated because until recently these were resistant to treatment with standard canalith repositioning procedures. Probably, the most significant factor in diagnosis of the type of BPPV is observation of the provoked nystagmus, during the diagnostic positional maneuvers. We describe in detail the various types of nystagmus, according to the canals involved, which are the keypoint to accurate diagnosis.

Cerebellar ataxia: pathophysiology and rehabilitation

This series of articles for rehabilitation in practice aims to cover a knowledge element of the rehabilitation medicine curriculum. Nevertheless they are intended to be of interest to a multidisciplinary audience. The competency addressed in this article is 'The trainee consistently demonstrates a knowledge of management approaches for specific impairments including spasticity, ataxia.'

Spontaneous nystagmus in benign paroxysmal positional vertigo

OBJECTIVE

The purpose of this study was to evaluate the presence and eventually to study the features of spontaneous nystagmus (Ny) in our patients with diagnosis of benign paroxysmal positional vertigo (BPPV).

PATIENTS AND METHODS

We retrospectively reviewed the clinical records of patients who presented with vertigo spells and were managed at our tertiary care referral center. Patients with only idiopathic BPPV presenting with typical vertigo spells and positioning Ny characteristic of the disease were included in this study. To investigate the positioning Ny, we studied the patients in the sitting position, during the head shaking test, and during the Dix-Hallpike test and the McClure-Pagnini test (Ny provoked by rotation of the head in a supine patient). Ny responses in all patients were observed using infrared videoscopy.

RESULTS

We managed 412 patients affected by BPPV. Of the 412 patients, 292 (70.87%) were diagnosed to be having posterior canal-BPPV and 110 (26.99%) patients had horizontal canal-BPPV (HC-BPPV). The remaining 10 patients (2.44%) were identified to have anterior canal-BPPV. Spontaneous Ny in sitting position was observed, by infrared videoscopy, only in the patients affected by HC-BPPV.

CONCLUSION

Spontaneous Ny in BPPV can be observed with infrared videoscopy in patients affected by HC-BPPV. The origin of this Ny is most likely due to a natural inclination of horizontal semicircular canal with respect to the horizontal plane. This Ny stops after flexion of the head in neutral position, and for this reason, it should be considered as a seemingly spontaneous Ny. This Ny, in our experience, is observed in most HC-BPPV patients but does not indicate the need for a different management protocol or any different prognostic value of HC-BPPV.