Dizziness

Unstable Gaze in Functional Dizziness: A Contribution to Understanding the Pathophysiology of Functional Disorders

Objective: We are still lacking a pathophysiological mechanism for functional disorders explaining the emergence and manifestation of characteristic, severely impairing bodily symptoms like chest pain or dizziness. A recent hypothesis based on the predictive coding theory of brain function suggests that in functional disorders, internal expectations do not match the actual sensory body states, leading to perceptual dysregulation and symptom perception. To test this hypothesis, we investigated the account of internal expectations and sensory input on gaze stabilization, a physiologically relevant parameter of gaze shifts, in functional dizziness. Methods: We assessed gaze stabilization in eight functional dizziness patients and 11 healthy controls during two distinct epochs of large gaze shifts: during a counter-rotation epoch (CR epoch), where the brain can use internal models, motor planning, and resulting internal expectations to achieve internally driven gaze stabilization; and during an oscillation epoch (OSC epoch), where, due to terminated motor planning, no movement expectations are present, and gaze is stabilized by sensory input alone. Results: Gaze stabilization differed between functional patients and healthy controls only when internal movement expectations were involved [F(1,17) = 14.63, p = 0.001, and partial η2 = 0.463]: functional dizziness patients showed reduced gaze stabilization during the CR (p = 0.036) but not OSC epoch (p = 0.26). Conclusion: While sensory-driven gaze stabilization is intact, there are marked, well-measurable deficits in internally-driven gaze stabilization in functional dizziness pointing at internal expectations that do not match actual body states. This experimental evidence supports the perceptual dysregulation hypothesis of functional disorders and is an important step toward understanding the underlying pathophysiology.

From illness perceptions to illness reality? Perceived consequences and emotional representations relate to handicap in patients with vertigo and dizziness

OBJECTIVE

Vertigo and dizziness (VD) are frequent symptoms that can occur due to various structural pathologies or due to functional impairment. Independent of their aetiology, the symptoms are often associated with physical and psychological burden which manifests in severe handicap in more than half of the patients. It is suggested that illness perceptions, the patients' cognitive and emotional concept of their disease, most likely impact the degree of handicap. For patients with VD, however, this relation of illness perceptions and handicap is so far not well understood. This study aimed to investigate the relation of illness perceptions and handicap for patients with VD.

METHODS

In a cross-sectional study design, n = 419 patients with VD were examined (53.7% female, age 53.5 ± 15.5 years). Participants underwent neurological and psychiatric examinations as well as a comprehensive assessment using self-report questionnaires.

RESULTS

Illness perceptions, specifically perceived consequences and emotional representations showed a moderate correlation with VD related handicap (r(419) = 0.62, p < .001). Our regression model including symptom severity, psychiatric comorbidity, and aspects of cognitive and emotional illness perceptions accounted for 52% of the variance in VD related handicap. In a moderation analysis, this relation did not differ significantly in patients with functional VD symptoms.

CONCLUSION

Findings of the present study provide evidence for the relevance of illness perceptions to handicap in patients with VD symptoms.

Course and predictors of DSM-5 somatic symptom disorder in patients with vertigo and dizziness symptoms - A longitudinal study

BACKGROUND

Somatic symptom disorder (SSD) is a diagnosis that was newly included in DSM-5. Currently, data on the course of SSD are largely lacking. The present study aimed to evaluate the natural course of SSD in a one-year follow-up study in patients with vertigo and dizziness (VD) symptoms.

METHODS

We investigated n=239 outpatients presenting in a tertiary care neurological setting over a one-year period. Patients had a medical examination at baseline and completed self-report questionnaires, which were re-assessed after 12months. DSM-5 SSD was assigned retrospectively. We evaluated the prevalence of SSD at baseline and 12-month follow-up and investigated predictors of the persistence of SSD during the study period.

RESULTS

The prevalence rate of SSD was 36% at baseline and 62% at 12-months follow-up. The persistence rate of SSD was 82% and the incidence rate was high, leading to a markedly increased prevalence rate at follow-up. Risk factors for persistent SSD were a self-concept of bodily weakness (OR: 1.52, 95% CI: 1.30-1.78) and an increase of depression during the study period (OR: 1.11, 95% CI: 1.02-1.22). Further, the diagnosis of an anxiety disorder (OR: 7.52, 95% CI: 1.17-48.23) or both anxiety and depressive disorder (OR: 23.14, 95% CI: 2.14-249.91) at baseline were significant predictors.

CONCLUSIONS

Our findings point out that SSD is highly prevalent in patients with VD symptoms, the incidence of the disorder widely outweighs its remission. Potential predictors of a persistence of SSD are discussed and can be chosen as a focus in therapy.

Psychological distress longitudinally mediates the effect of vertigo symptoms on vertigo-related handicap

OBJECTIVE

Vertigo symptoms can lead to more or less vertigo-related handicap. This longitudinal study investigated whether depression, anxiety, and/or somatization mediate the relationship between vertigo symptoms and vertigo-related handicap.

METHODS

N=111 patients with vertigo/dizziness provided complete data on the following measures: Vertigo symptoms at baseline, depression at 6-month follow-up, anxiety at 6-month follow-up, somatization at 6-month follow-up, and vertigo handicap at 12-month follow-up. Mediation analyses with bootstrapping were performed to investigate the mediating role of anxiety, depression, and somatization in the relationship between vertigo symptoms and vertigo-related handicap.

RESULTS

When the mediating role of anxiety, depression, and somatization was evaluated separately from each other in single mediation models, the effect vertigo symptoms at baseline exerted on vertigo-related handicap at 12-month follow-up was significantly mediated by depression at 6-month follow-up (p<0.05), by anxiety at 6-month follow-up (p<0.05), as well as by somatization at 6-month follow-up (p<0.05). When statistically controlling for the other mediators in a multiple mediator model, only depression at 6-month follow-up mediated the effect of vertigo symptoms at baseline on vertigo-related handicap at 12-month follow-up (p<0.05).

CONCLUSION

Psychological distress is an important mechanism in the process how vertigo symptoms lead to vertigo-related handicap.

DSM-5 somatic symptom disorder in patients with vertigo and dizziness symptoms

OBJECTIVE

DSM-5 somatic symptom disorder (SSD) could potentially be a highly relevant diagnosis for patients with vertigo and dizziness. The criteria of SSD, particularly the B-criterion with its three components (cognitive, affective, behavioral), have however not yet been investigated in this patient group.

METHODS

We evaluated a large sample (n=399) of outpatients presenting in a neurological setting. Physical examinations and a psychometric assessment (SCID-I) were conducted; patients completed self-report questionnaires. The diagnosis of SSD was assigned retrospectively. The prevalence of SSD, its diagnostic criteria, and its overlap with former DSM-IV somatoform disorders were evaluated; comparisons were drawn between (1) patients fulfilling different components of the B-criterion and (2) patients with diagnoses after DSM-IV vs. DSM-5.

RESULTS

SSD was almost twice as common as DSM-IV somatoform disorders. Patients with all three components of the B-criterion reported the highest impairment levels. Patients with both DSM-IV somatoform disorders and DSM-5 SSD were more impaired compared to groups with one of the diagnoses; patients with DSM-IV somatoform disorders only were more impaired than those with SSD only.

CONCLUSIONS

Our findings demonstrate that SSD is highly prevalent in patients with vertigo and dizziness. The classification of severity based on the number of psychological symptoms appears valid and may assist in finding suitable treatment options according to clinical practice guidelines. Future studies should investigate the overlap of SSD and other psychiatric disorders, this may assist in better defining the diagnostic criteria of SSD.

Current concepts and future approaches to vestibular rehabilitation

Over the last decades methods of vestibular rehabilitation to enhance adaptation to vestibular loss, habituation to changing sensory conditions, and sensory reweighting in the compensation process have been developed. However, the use of these techniques still depends to a large part on the educational background of the therapist. Individualized assessment of deficits and specific therapeutic programs for different disorders are sparse. Currently, vestibular rehabilitation is often used in an unspecific way in dizzy patients irrespective of the clinical findings. When predicting the future of vestibular rehabilitation, it is tempting to foretell advances in technology for assessment and treatment only, but the current intense exchange between clinicians and basic scientists also predicts advances in truly understanding the complex interactions between the peripheral senses and central adaptation mechanisms. More research is needed to develop reliable techniques to measure sensory dependence and to learn how this knowledge can be best used--by playing off the patient's sensory strength or working on the weakness. To be able using the emerging concepts, the neuro-otological community must strive to educate physicians, physiotherapists and nurses to perform the correct examinations for assessment of individual deficits and to look for factors that might impede rehabilitation.

Psychological traumatization and adverse life events in patients with organic and functional vestibular symptoms

OBJECTIVE

. A relationship has frequently been found between a history of traumatization and the existence of somatoform symptoms. The objective of this study was to examine whether this relationship is also observed for functional, i.e. medically not sufficiently explained, vestibular symptoms (FVS). We tested whether patients with FVS and organically explained vestibular symptoms (OVS) differ with regard to frequencies of previous traumatic experiences and posttraumatic stress symptoms. We also explored whether the impact of previous trauma was associated with characteristics of vestibular symptoms and handicap.

METHODS

. Patients with a diagnosis of OVS (N=185) or FVS (N=158) completed questionnaires about potentially traumatizing experiences (e.g., Childhood Trauma Questionnaire, Impact of Events Scale) and vertigo-related symptoms and handicap (Vertigo Symptom Scale, Vertigo Handicap Questionnaire).

RESULTS

. We found no differences between the two patient groups with regard to number or impact of traumatic life events. However, regression analyses across groups revealed that, regardless of their diagnosis, prior traumatic experiences and the presence of posttraumatic stress symptoms including avoidance and intrusion predicted to some extent higher overall balance symptoms and autonomic symptoms of vertigo-related anxiety.

CONCLUSION

. Exposure to trauma and symptoms of posttraumatic stress can contribute to symptom severity and handicap experienced by patients with vestibular symptoms irrespective of their original cause, most likely serving as predisposing, modulating or perpetuating factors.

Vertigo/dizziness as a Drugs' adverse reaction

INTRODUCTION

Vertigo, dizziness, and nausea encompass a spectrum of balance-related symptoms caused by a variety of etiologies. Balance is affected by many systems: Proprioceptive pathways and visual, cerebellar, vestibulocochlear, and vascular / vasovagal systems. Vertigo is a subtype of dizziness, in which a subject, as a result to a dysfunction of the vestibular system, improperly experiments the perception of motion. The most useful clinical subdivision is to categorize vertigo into true vertigo and pseudovertigo, whereas from a pathophysiological point of view, vertigo can be classified into central, peripheral, and psychogenic. It is not easy to identify the cause of vertigo since the patients often are not able to precisely describe their symptoms. An impressive list of drugs may cause vertigo or dizziness.

MATERIALS AND METHODS

The aim of the present study was to analyze the data extracted from the reporting cards of the ADRs (adverse drug reactions), received at our Pharmacovigilance Regional Center (Calabria, Italy) in 2012. In particular, the data concerning the occurrence of vertigo and dizziness, after taking certain classes of drugs, have been considered.

RESULTS

Our results show that, among the side-effects of different classes of drugs such as anti-convulsants, anti-hypertensives, antibiotics, anti-depressants, anti-psychotics, and anti-inflammatory, also vertigo or dizziness are included.

CONCLUSIONS

Spontaneous reports of vertigo or dizziness, as side-effect of certain drugs, received at our Pharmacovigilance Center, represented the 5% of all reports in 2012. Considering the high incidence of such an ADR for several drugs' classes, it can be speculated that under-reporting also affect vertigo and dizziness. Despite the fact that these ADRs might not represent a direct threaten for life, indirectly they can cause secondary damage to patients such as falls, fractures etc. Balance should be accurately monitored during drug use and particularly in fragile patients.

Pharmacodynamic differentiation of lorazepam sleepiness and dizziness using an ordered categorical measure

Categorical measures of lorazepam sleepiness and dizziness were modeled to identify differences in pharmacodynamic (PD) parameters between these adverse events (AEs). Differences in data-derived PD parameters were compared with relative incidence rates in the drug label (15.7% and 6.9%, respectively). Healthy volunteers (n = 20) received single oral doses of 2 mg lorazepam or placebo in a randomized, double-blind, cross-over fashion. A seven-point categorical scale measuring the intensity of AEs was serially administered over 24 h. The maximum score (MaxS), and area under the effect curve (AUEC) were determined by noncompartmental methods and compared using a paired t-test. Individual scores were modeled using a logistic function implemented in NONMEM. AUEC and MaxS for sleepiness were significantly higher than dizziness (20.35 vs. 9.76, p < 0.01) and (2.35 vs. 1.45, p < 0.01). Model slope estimates were similar for sleepiness and dizziness (0.21 logits x mL/ng vs. 0.19 logits x mL/ng), but baseline logits were significantly higher for sleepiness (-2.81 vs. -4.34 logits). Data-derived PD parameters were in concordance with label incidence rates. The higher intensity of sleepiness may be directly related to baseline (no drug present) while the increase in intensity as a result of drug was relatively similar for both AEs.

[Chronic dizziness in elderly people: its clinical characteristics and magneto-encephalographic findings]

Many elderly people complain dizziness which may continue occasionally for months or years. According to epidemiological studies, 25-29% of subjects with more than 60 years of age have the experience of dizziness. Dizziness occurs most commonly during head positional changes or walking. Clinical studies have indicated that causes of dizziness are nonspecific and multi-factorial; cerebrovascular diseases, cervical spondylosis, depressive state, poor vision, orthostatic hypotension, whiplash injury, or low cerebrospinal fluid syndrome may play a role in the development of dizziness. Patients with dizziness commonly have neck/shoulder pain, insomnia, left-right imbalance of visual acuity, scoliosis, white matter lesions on head MRI. Little, however, has yet been known as to how these symptoms and radiological findings are related to mechanisms of dizziness. During the last several years, we performed cerebral functional studies using auditory-evoked magneto-encephalography (MEG) in elderly people with chronic dizziness. Two types of functional abnormalities were found in dizziness patients. One is a rotational abnormality of MEG signals at the temporal cortex (Type A) which can be detected by current arrow mapping analysis. This abnormality is similar to that detected by non-evoked MEG in temporal lobe epilepsy patients. In patients with Type A abnormality, administration of anticonvulsants brought about dramatic improvement of dizziness in association with disappearance of rotational abnormalities. The other is abnormal prolongation of interhemispheric neural conduction time (INCT) between the left and right temporal cortices (Type B) which can be estimated from the difference of left and right N100 m peak latencies. The INCT was found to be prolonged correlating with the grade of white matter lesions on MRI. The INCT also seems to be prolonged by lack of sleep. Patients with Type B abnormality commonly have the asymmetry of body, such as left-right imbalance of visual acuity, left-right neck pain, or remarkable scoliosis, in association with insomnia and/or depressive state. According to the study of Penfield, dizziness or vertigo is manifested by stimulation of upper temporal cortex and lower parietal cortex. Mechanisms of dizziness can be hypothecated on the basis of MEG findings as follows: Presumably, there are head-position recognizing (HPR) centers in the left and right cerebral hemispheres. The HPR centers may correspond to the vestibular cortex or the combined system of vestibular, visual and somatosensory cortices. The HPR centers in two hemispheres are receiving head-position signals from vestibular, visual and somatosensory corices and are readjusting the dissociation of information which may exist between each other through rapid interhemispheric neural conduction. In patients with Type A abnormality, dizziness may be caused by abnormal neuronal excitements in left or right HPR center. In patients with Type B abnormalities, dizziness may be caused by the combined factors, one the abnormal prolongation of INCT between left and right HPR centers and the other the large dissociation of head position signals between the left and right HPR centers due to the body asymmetry, such as scoliosis or left-right neck pain imbalance.

Treatment of vestibular schwannomas. Why, when and how?

Sporadic vestibular schwannoma (VS) causes unilateral hearing loss, tinnitus, vertigo and unsteadiness. In many cases, the tumour size may remain unchanged for many years following diagnosis, which is typically made by MRI. In the majority of cases the tumour is small, leaving the clinician and patient with the options of either serial scanning or active treatment by gamma knife radiosurgery (GKR) or microneurosurgery. Despite the vast number of published treatment reports, comparative studies are few, and evidence is no better than class III (May, 2006). The predominant clinical endpoints of VS treatment include tumour control, facial nerve function and hearing preservation. Less focus has been put on symptom relief and health-related quality of life (QOL). It is uncertain if treating a small tumour leaves the patient with a better chance of obtaining relief from future hearing loss, vertigo or tinnitus than by observing it without treatment. Recent data indicate that QOL is reduced in untreated VS patients, and may differ between patients who have been operated and patients treated with GKR. In the present paper we review the natural course and complaints of untreated VS patients, and the treatment alternatives and results. Furthermore, we review the literature concerning quality of life in patients with VS. Finally, we present our experience with a management strategy applied to more than 300 cases since 2001.

Mefloquine induces dose-related neurological effects in a rat model

Mefloquine is one of the drugs approved by the FDA for malaria chemoprophylaxis. Mefloquine is also approved for the treatment of malaria and is widely used for this purpose in combination with artesunate. However, the clinical utility of the compound has been compromised by reports of adverse neurological effects in some patients. In the present study, the potential neurological effects of mefloquine were investigated with six 7-week-old female rats given a single oral dose of the compound. Potential mefloquine-induced neurological effects were monitored using a standard functional observational battery, automated open field tests, automated spontaneous activity monitoring, a beam traverse task, and histopathology. Plasma mefloquine concentrations were determined 72 h after dosing by using liquid chromatography-mass spectrometry. Mefloquine induced dose-related changes in endpoints associated with spontaneous activity and impairment of motor function and caused degeneration of specific brain stem nuclei (nucleus gracilis). Increased spontaneous motor activity was observed only during the rats' normal sleeping phase, suggesting a correlate to mefloquine-induced sleep disorders. The threshold dose for many of these effects was 187 mg/kg of body weight. This dose yielded plasma mefloquine concentrations after 72 h that are similar to those observed in humans after the treatment dose. Collectively, these data suggest that there may be a biological basis for some of the clinical neurological effects associated with mefloquine.

Acute Vestibular Neuritis: Prognosis Based upon Bedside Clinical Tests (Thrusts and Heaves)

We compared bedside tests of vestibulo-ocular function (head thrust and head heave signs) with caloric testing results in 68 patients with acute vestibular neuritis seen at onset and in follow-up for one year. The head thrust and head heave signs each were strong predictors of a decreased probability of recovery, and if both were present, there was a trend for a slower recovery and a further decrease in the probability of recovery. If the head thrust sign was absent, recovery was assured. Our results suggest that careful bedside testing of semicircular canal (head thrust maneuver) and otolith (head heave maneuver) function provides useful information for predicting prognosis in patients with acute vestibular neuritis.

Microcirculatory effects of a homeopathic preparation in patients with mild vertigo: an intravital microscopic study

The effects of the homeopathic preparation Vertigoheel on variables related to microcirculation were investigated using vital microscopy techniques in patients with vestibular vertigo. In a non-randomized, open study, 16 patients given Vertigoheel were compared with 16 untreated patients. Measurements were carried out in two areas (defined by selecting 60 blood-cell perfused nodal points of arterioles, venules, and capillaries with a mean diameter > or = 40 microm): the cuticulum/subcuticulum of the inside left lower arm and an area 5 mm behind the left earlobe. After 12 weeks of treatment, patients receiving the homeopathic preparation exhibited an increased number of nodal points, increased flow rates of erythrocytes in both arterioles and venules, increased vasomotion, and a slight reduction in hematocrit vs. baseline. None of these changes were observed in the control group and the differences between treatment groups were statistically significant. Partial oxygen pressure increased significantly in the Vertigoheel group compared with the control group. In addition, in Vertigoheel patients, significantly increased numbers of cell-wall adhering leucocytes were observed, accompanied by increased local concentrations of the adhesion molecules ICAM-1. The microcirculatory changes were associated with a reduction in the severity of vertigo in the actively treated patients, both as assessed by the treating physician and by the patients themselves. The data support a pharmacological effect on microcirculation from the treatment.