Chronic dizziness: the interface between psychiatry and neuro-otology

A multivariate statistical and data mining analysis of spatial memory-related behaviour following bilateral vestibular loss in the rat

Vestibular dysfunction in animals and humans is associated with a variety of cognitive and anxiety disorders, and it has been difficult to determine how the different symptoms may be related to one another. The aim of this study was to determine the extent to which the spatial memory deficits that occur following bilateral vestibular deafferentation (BVD) in rats can be attributed to other behavioural symptoms. Spatial memory was measured using a spatial T maze alternation task (STM), while locomotor activity and anxiety were measured using open field, elevated plus and T mazes, respectively. Using multiple linear and random forest regression, we determined that the best predictors of performance in the STM were whether the animals had received a BVD or sham lesion, and the duration of rearing. Using linear discriminant analysis, random forest classification, support vector machines and cluster analysis, we found that BVD animals could be clearly distinguished from sham controls by their behavioural syndrome, in particular their decreased duration of rearing in the open field maze (suggesting reduced exploration), decreased time spent in the outer zone of the open field maze ('reduced thigmotaxis', suggesting increased risk taking), and spatial memory deficits in the STM. These results suggest that the poor performance of rats with BVD in spatial memory tasks is largely due to spatial memory deficits themselves rather than a result of other changes in locomotor activity or anxiety.

Cremer P. Cognitive behavior therapy for chronic subjective dizziness: longer-term gains and predictors of disability

PURPOSE

The study sought to evaluate the longer-term effects of a brief cognitive behavior therapy (CBT) intervention for patients with chronic subjective dizziness (CSD). In addition, it sought to identify predictors of longer-term disability in this group.

MATERIALS AND METHODS

Forty-four patients with CSD referred by a neuro-otological clinic were followed-up six months after completing a brief treatment program based on the CBT model of panic disorder. Patients completed the following measures: Dizziness Handicap Inventory, Depression, Anxiety and Stress Scales, Dizziness Symptoms Inventory, and the Safety Behaviours Inventory. Measures were completed at pre and post-treatment, as well as at one and six months post-treatment.

RESULTS

Treatment gains observed immediately after treatment were maintained at one and six months post-treatment. High levels of pre-treatment anxiety predicted higher levels of disability at six months post-treatment. Duration and severity of dizziness, and medical or psychiatric comorbidity did not predict disability at six month follow-up.

CONCLUSIONS

A brief CBT intervention for patients with CSD produced improvements in physical symptoms, disability, and functional impairment which were sustained at one month and six months post intervention. Patients with high levels of anxiety prior to treatment had higher levels of disability at six months post-treatment. It is possible that more focused interventions that specifically target anxiety might produce further benefits for this cohort.

Review of somatic symptoms in post-traumatic stress disorder

Post-traumatic stress disorder (PTSD) is associated with both (1) 'ill-defined' or 'medically unexplained' somatic syndromes, e.g. unexplained dizziness, tinnitus and blurry vision, and syndromes that can be classified as somatoform disorders (DSM-IV-TR); and (2) a range of medical conditions, with a preponderance of cardiovascular, respiratory, musculoskeletal, neurological, and gastrointestinal disorders, diabetes, chronic pain, sleep disorders and other immune-mediated disorders in various studies. Frequently reported medical co-morbidities with PTSD across various studies include cardiovascular disease, especially hypertension, and immune-mediated disorders. PTSD is associated with limbic instability and alterations in both the hypothalamic- pituitary-adrenal and sympatho-adrenal medullary axes, which affect neuroendocrine and immune functions, have central nervous system effects resulting in pseudo-neurological symptoms and disorders of sleep-wake regulation, and result in autonomic nervous system dysregulation. Hypervigilance, a central feature of PTSD, can lead to 'local sleep' or regional arousal states, when the patient is partially asleep and partially awake, and manifests as complex motor and/or verbal behaviours in a partially conscious state. The few studies of the effects of standard PTSD treatments (medications, CBT) on PTSD-associated somatic syndromes report a reduction in the severity of ill-defined and autonomically mediated somatic symptoms, self-reported physical health problems, and some chronic pain syndromes.

Acute constant dizziness

PURPOSE OF REVIEW

This article describes an approach to the diagnosis and management of acute constant dizziness, one of the most unnerving presentations in medicine. Patients with acute constant dizziness can be completely debilitated by the symptoms. Most cases are caused by a self-limited disorder, typically vestibular neuritis. However, a significant proportion of cases harbor a stroke that could be life threatening. Discriminating a self-limited disorder from a life-threatening disorder can be challenging and often hinges on findings, which may be subtle, from the ocular motor examination.

RECENT FINDINGS

Early research indicates that bedside ocular motor findings play a critical role in differentiating vestibular neuritis from stroke.

SUMMARY

This article describes an approach to the patient with acute constant dizziness.

Anxiety in a dizzy patient: the importance of communication in improving outcome

Most patients with dizziness have a benign self-limited condition, often of labyrinthine origin; however, some develop a more intractable form of dizziness that can be challenging to evaluate. In many of these patients, brain imaging, vestibular testing, and clinical examination are normal, but the patient is significantly impaired. Many such patients have coexisting anxiety, which can make it difficult to determine whether the anxiety is a reaction to the dizziness or its primary cause. A careful history, including an assessment of the impact of symptoms on quality-of-life, social, and work-related issues is critical, and effective patient communication is essential. The following case exemplifies how a high-functioning person can become severely limited because of the complex intertwining of several types of dizziness with anxiety.

Dyscalculia and vestibular function

BACKGROUND

A few studies in humans suggest that changes in stimulation of the balance organs of the inner ear (the 'vestibular system') can disrupt numerical cognition, resulting in 'dyscalculia', the inability to manipulate numbers. Many studies have also demonstrated that patients with vestibular dysfunction exhibit deficits in spatial memory.

OBJECTIVES

It is suggested that there may be a connection between spatial memory deficits resulting from vestibular dysfunction and the occurrence of dyscalculia, given the evidence that numerosity is coupled to the processing of spatial information (e.g., the 'spatial numerical association of response codes ('SNARC') effect').

RESULTS AND CONCLUSION

The evidence supporting this hypothesis is summarised and potential experiments to test it are proposed.

Performance in anxiety and spatial memory tests following bilateral vestibular loss in the rat and effects of anxiolytic and anxiogenic drugs

Vestibular dysfunction in humans is associated with anxiety and cognitive disorders. However, various animal studies of the effects of vestibular loss have yielded conflicting results, from reduced anxiety to increased anxiety, depending on the particular model of vestibular dysfunction and the anxiety test used. In this study we revisited the question of whether rats with surgical bilateral vestibular deafferentation (BVD) exhibit changes in anxiety-related behaviour by testing them in the open field maze (OFM), elevated plus maze (EPM) and elevated T maze (ETM) in the presence of a non-sedating anxiolytic drug, buspirone, or an anxiogenic drug, FG-7142. We also tested the animals in a spatial T maze (STM) in order to evaluate their cognitive function under the same set of conditions. We found that BVD animals exhibited increased locomotor activity (P≤0.003), reduced supported and unsupported rearing (P≤0.02 and P≤0.000, respectively) and reduced thigmotaxis (P≤0.000) in the OFM, which for the most part the drugs did not modify. By contrast, there were no significant differences between BVD and sham control animals in the EPM and the BVD animals exhibited a marginally longer escape latency in the ETM (P≤0.03), with no change in avoidance latency. In the STM, the BVD animals demonstrated a large and significant decrease in accuracy compared to the sham control animals (P≤0.000), which was not affected by drug treatment. These results have replicated previous findings regarding increased locomotor activity, reduced rearing and thigmotaxis in the OFM, and impaired performance in the STM. However, they failed to replicate some previous results obtained using the EPM and ETM. Overall, they do not support the hypothesis that BVD animals exhibit increased anxiety-like behaviour and suggest that the cognitive deficits may be independent of the emotional effects of vestibular loss.

Cognitive behavior therapy for chronic subjective dizziness: a randomized, controlled trial

PURPOSE

The aim of this study was to evaluate the effects of a brief cognitive behavior therapy (CBT) intervention on the physical symptoms, illness-related disability, and psychologic distress of patients with chronic subjective dizziness.

MATERIALS AND METHODS

Forty-one patients with chronic subjective dizziness referred by a neurootologic clinic were randomly assigned to immediate treatment or a wait-list control. Three weekly treatment sessions based on the CBT model of panic disorder, adapted for patients with dizziness, were administered by a clinical psychologist. Treatment included psychoeducation, behavioral experiments, exposure to feared stimuli, and attentional refocusing. Outcomes were measured on the Dizziness Handicap Inventory and the Depression, Anxiety and Stress Scales. Two further measures developed for this study; the Dizziness Symptoms Inventory and the Safety Behaviours Inventory were used to measure physical symptoms and safety behaviors.

RESULTS

The intervention was associated with significant reductions in disability on the Dizziness Handicap Inventory, reduced dizziness and related physical symptoms on the Dizziness Symptoms Inventory, and reduced avoidance and safety behaviors as measured by the Safety Behaviours Inventory. Pre- to posteffect sizes ranged from 0.98 to 1.15. There was no change in psychologic outcomes measured on the Depression, Anxiety and Stress Scales.

CONCLUSIONS

A 3-session psychologic intervention based on the CBT model can produce significant improvements in dizziness-related symptoms, disability, and functional impairment among patients with chronic subjective dizziness. This suggests that treatment of this condition may be reasonably simple and cost-effective for most of the patients.

Antianxiety medications for the treatment of complex agoraphobia: pharmacological interventions for a behavioral condition

BACKGROUND

Although there are controversial issues (the "American view" and the "European view") regarding the construct and definition of agoraphobia (AG), this syndrome is well recognized and it is a burden in the lives of millions of people worldwide. To better clarify the role of drug therapy in AG, the authors summarized and discussed recent evidence on pharmacological treatments, based on clinical trials available from 2000, with the aim of highlighting pharmacotherapies that may improve this complex syndrome.

METHODS

A systematic review of the literature regarding the pharmacological treatment of AG was carried out using MEDLINE, EBSCO, and Cochrane databases, with keywords individuated by MeSH research. Only randomized, placebo-controlled studies or comparative clinical trials were included.

RESULTS

After selection, 25 studies were included. All the selected studies included patients with AG associated with panic disorder. Effective compounds included selective serotonin reuptake inhibitors, serotonin-norepinephrine reuptake inhibitors, tricyclic antidepressants, selective noradrenergic reuptake inhibitors, and benzodiazepines. Paroxetine, sertraline, citalopram, escitalopram, and clomipramine showed the most consistent results, while fluvoxamine, fluoxetine, and imipramine showed limited efficacy. Preliminary results suggested the potential efficacy of inositol; D-cycloserine showed mixed results for its ability to improve the outcome of exposure-based cognitive behavioral therapy. More studies with the latter compounds are needed before drawing definitive conclusions.

CONCLUSION

No studies have been specifically oriented toward evaluating the effect of drugs on AG; in the available studies, the improvement of AG might have been the consequence of the reduction of panic attacks. Before developing a "true" psychopharmacology of AG it is crucial to clarify its definition. There may be several potential mechanisms involved, including fear-learning processes, balance system dysfunction, high light sensitivity, and impaired visuospatial abilities, but further studies are warranted.

Behavioral models for anxiety and multisensory integration in animals and humans

Complaints related to dizziness, balance problems and spatial disorientation in psychiatry have seldom been considered as a possible manifestation of a distorted multisensory integrative ability. Several kinds of mismatches among simultaneous sensory information are encountered in everyday life but despite these, the central nervous system usually manages to update the internal representation of the body in the surrounding space. In some cases, a sensory mismatch may elicit an erroneous perception of the body in space, resulting in anxiety, dizziness and balance problems. As vestibular system dysfunction leads to dizziness and disorientation, it has been hypothesized that a peripheral vestibular abnormality could explain the presence of certain symptoms related to sensory mismatches in anxiety disorders. Several studies tried to find a link between panic disorder with or without agoraphobia and vestibular system dysfunction. Yet, even though some vestibular abnormalities have been demonstrated in these patients, it is difficult to demonstrate a cause-and-effect relationship between panic disorder and vestibular dysfunction. However, this does not rule out a possible influence of anxiety on normal vestibular function. The study of the relation between vestibular system and anxiety has to take into account that the vestibular system has three main functions: to maintain equilibrium through the vestibular spinal reflexes; to stabilize the visualization of the world through the vestibular-ocular reflex; to contribute to perception and orientation in space. We will review different studies in humans, which have particularly paid attention to the third function and its relation to anxiety. Animal experiments offer possibilities to more precisely analyze the different parameters underlying the behavioral results, as well as possible pharmacological actions on them. Two attempts have been made by our group to model, in mice, the preceding human data on integrated functional sensory relations of the body to space in anxiety disorders: the rotating beam and the rotating tunnel. We summarize here the main results obtained.

Is there a hypersensitive visual alarm system in panic disorder?

Agoraphobia in panic disorder (PD) has been related to abnormal balance system function. Vision influences balance and behavioural adaptations; peripheral vision influences orienting and fast defensive reactions whereas central vision analyzes details of objects. We have hypothesized that the abnormal balance function in PD could be mainly related to peripheral vision as part of a defensive alarm system in the brain. In 25 patients with PD and agoraphobia and 31 healthy controls we assessed, by posturography, balance system reactivity to video-films projected in peripheral and central visual fields (randomized sequence). Length, velocity and surface of body sway were calculated. Patients increased their body sway during peripheral stimulation, whereas controls did not; the two groups showed a similar increase of body sway during central stimulation. Anxiety levels during peripheral stimulation significantly influenced the postural response in the group of patients. These preliminary results suggest that the higher visual sensitivity to peripheral stimulation in patients with PD and agoraphobia may be linked to a more active "visual alarm system" involving visual, vestibular and limbic areas that might influence the development of agoraphobia in situations where environmental stimuli are uncertain.

Imipramine for vestibular dysfunction in panic disorder: a prospective case series

OBJECTIVE: The purpose of this study was to evaluate the efficacy and effectiveness of imipramine on the treatment of comorbid chronic dizziness and panic disorder. METHOD: Nine patients with panic disorder and agoraphobia associated with chronic dizziness underwent otoneurological screening and were treated with a 3-months course of imipramine. Anxiety levels were measured with the Hamilton Anxiety Scale (HAM-A), dizziness levels were evaluated using the Dizziness Handicap Inventory (DHI), and panic severity and treatment outcome were assessed with the Clinical Global Impression Scale (CGI). RESULTS: At the baseline 33.3% (n=3) had a bilateral peripheral deficit vestibulopathy, the mean scores for HAM-A were 27.2±10.4, for DHI were 51.7±22.7, and for CGI-S were 4.8±0.9. All patients had a significant reduction in their HAM-A (11.1±5.5, p=0.008), DHI (11.5±8.1, p=0.008) and CGI-I (1.8±0.7, p=0.011) levels after 3-months imipramine treatment (mean=72.2±23.2 mg/day). CONCLUSION: This study found a decrease in anxiety levels and in the impact of dizziness in the patients' quality of life after a 3-months treatment course with imipramine.

Neurologic bases for comorbidity of balance disorders, anxiety disorders and migraine: neurotherapeutic implications

The comorbidity among balance disorders, anxiety disorders and migraine has been studied extensively from clinical and basic research perspectives. From a neurological perspective, the comorbid symptoms are viewed as the product of sensorimotor, interoceptive and cognitive adaptations that are produced by afferent interoceptive information processing, a vestibulo-parabrachial nucleus network, a cerebral cortical network (including the insula, orbitofrontal cortex, prefrontal cortex and anterior cingulate cortex), a raphe nuclear-vestibular network, a coeruleo-vestibular network and a raphe-locus coeruleus loop. As these pathways overlap extensively with pathways implicated in the generation, perception and regulation of emotions and affective states, the comorbid disorders and effective treatment modalities can be viewed within the contexts of neurological and psychopharmacological sites of action of current therapies.

Principles of vestibular physical therapy rehabilitation

The use of vestibular rehabilitation for persons with balance and vestibular disorders is used to improve function and decrease dizziness symptoms. Principles of a vestibular rehabilitation program are described including common exercises and outcome measures used to report change. A review of negative and positive predictive factors related to recovery is also provided.

Modulation of memory by vestibular lesions and galvanic vestibular stimulation

For decades it has been speculated that there is a close association between the vestibular system and spatial memories constructed by areas of the brain such as the hippocampus. While many animal studies have been conducted which support this relationship, only in the last 10 years have detailed quantitative studies been carried out in patients with vestibular disorders. The majority of these studies suggest that complete bilateral vestibular loss results in spatial memory deficits that are not simply due to vestibular reflex dysfunction, while the effects of unilateral vestibular damage are more complex and subtle. Very recently, reports have emerged that sub-threshold, noisy galvanic vestibular stimulation can enhance memory in humans, although this has not been investigated for spatial memory as yet. These studies add to the increasing evidence that suggests a connection between vestibular sensory information and memory in humans.

Different types of dizziness in patients with peripheral vestibular diseases--their prevalence and relation to migraine

CONCLUSIONS

Besides spontaneous attacks of vertigo or unsteadiness, other symptoms, i.e. drop attacks, lateropulsion, illusions that the room or body is tilted, 'walking on pillows' or 'stepping into a hole', occur without precipitating head movement in almost 50% of patients with peripheral vestibular dysfunctions. The sensation of static tilt was closely connected to migraine and Meniere's disease (MD).

OBJECTIVES

To record the prevalence of the different symptoms with respect to vestibular diagnosis and its relation to migraine.

METHODS

Data from 100 patients with MD, benign paroxysmal positional vertigo (BPPV), or unilateral peripheral vestibular impairment (UPVI) were analyzed with respect to vestibular diagnosis and migraine as a secondary diagnosis.

RESULTS

Spontaneous attacks of vertigo or unsteadiness occurred in 74% and 48% of patients, respectively. Vertigo was significantly more often reported in patients with MD and BPPV. In patients with BPPV, the duration of spontaneous vertigo was shorter than in patients with MD. The relative incidence of other symptoms were: unsteadiness, 48%; 'stepping into a hole', 46%; lateropulsion, 35%; 'walking on pillows', 21%; and drop attacks, 19%. Only the sensation of static tilt, which occurred in 8% of patients, was significantly correlated to MD or to migraine.

Chronic Subjective Dizziness Versus Conversion Disorder: Discussion of Clinical Findings and Rehabilitation

Purpose

Audiologists frequently encounter patients who complain of chronic dizziness or imbalance, in the absence of active vestibular or neurological deficits. Knowledge about conditions that cause this clinical presentation will allow audiologists to make important contributions to accurate diagnosis and effective management of these patients. This article reviews 2 such conditions, chronic subjective dizziness (CSD) and conversion disorder.

Method

A case of CSD and another of conversion disorder are presented, with a literature review of their clinical presentations, key diagnostic features, and treatment strategies. The role of the audiologist in assessing patients with these conditions and facilitating appropriate treatment referrals is discussed.

Conclusions

The audiologist is in a key position to identify individuals with CSD and conversion disorder, 2 conditions that can be effectively managed if properly recognized. The authors demonstrate an effective team approach program that includes the audiologist’s contribution to differential diagnosis, education of patients and other clinicians about these conditions, and development of recommendations for neurological, psychiatric, otologic, and physical therapy referrals.

Psychological assessment in patients with phobic postural vertigo

Phobic postural vertigo (PPV) is a frequent diagnosis which can be challenging to treat.

OBJECTIVE

To investigate the presence of psychiatric disturbances in patients with PPV; to assess the psychological status of patients using adaptive diagnosis; to verify possible correlations between severity of psychiatric disturbance and adaptive efficacy.

METHOD

A total of nineteen subjects were assessed and two instruments applied: the Primary Care Evaluation of Mental Disorders Questionnaire (PRIME-MD) and the Adaptive Operationalized Diagnostic Scale (AODS), and results from both tests were compared.

RESULTS

Fourteen patients presented with mood disorder and thirteen with anxiety. All patients presented compromised adaptive efficacy. Correlation was found between overall outcome on the PRIME and the AODS (tau= -0.42, p=0.027), Separate analysis revealed correlation between results of the AODS and anxiety disorders (tau= -0.45, p=0.018) but not with mood disorders (tau= -0.36, p=0.054).

CONCLUSION

Adaptive compromise was observed in individuals with PPV which was shown to be associated to psychiatric disorders.

Move it or lose it--is stimulation of the vestibular system necessary for normal spatial memory?

Studies in both experimental animals and human patients have demonstrated that peripheral vestibular lesions, especially bilateral lesions, are associated with spatial memory impairment that is long-lasting and may even be permanent. Electrophysiological evidence from animals indicates that bilateral vestibular loss causes place cells and theta activity to become dysfunctional; the most recent human evidence suggests that the hippocampus may cause atrophy in patients with bilateral vestibular lesions. Taken together, these studies suggest that self-motion information provided by the vestibular system is important for the development of spatial memory by areas of the brain such as the hippocampus, and when it is lost, spatial memory is impaired. This naturally suggests the converse possibility that activation of the vestibular system may enhance memory. Surprisingly, there is some human evidence that this may be the case. This review considers the relationship between the vestibular system and memory and suggests that the evolutionary age of this primitive sensory system as well as how it detects self-motion (i.e., detection of acceleration vs. velocity) may be the reasons for its unique contribution to spatial memory.

Dizziness, migrainous vertigo and psychiatric disorders

OBJECTIVES

This study sought to establish the prevalence of vestibular disorders, migraine and definite migrainous vertigo in patients with psychiatric disorders who were referred for treatment of dizziness, without a lifetime history of vertigo.

STUDY DESIGN

Retrospective study.

SETTING

Out-patients in a university hospital.

MATERIALS AND METHODS

Fifty-two dizzy patients with panic disorders and agoraphobia, 30 with panic disorders without agoraphobia, and 20 with depressive disorders underwent otoneurological screening with bithermal caloric stimulation. The prevalence of migraine and migrainous vertigo was assessed. The level of dizziness was evaluated using the Dizziness Handicap Inventory.

RESULTS

Dizzy patients with panic disorders and agoraphobia had a significantly p = 0.05 regarding the prevalence of peripheral vestibular abnormalities in the group of subjects with PD and agoraphobia and in those with depressive disorders. Migraine was equally represented in the three groups, but panic disorder patients had a higher prevalence of migrainous vertigo definite migrainous vertigo. Almost all patients with a peripheral vestibular disorder had a final diagnosis of definite migrainous vertigo according to Neuhauser criteria. These patients had higher Dizziness Handicap Inventory scores. The Dizziness Handicap Inventory total score was higher in the subgroup of patients with panic disorders with agoraphobia also presenting unilateral reduced caloric responses or definite migrainous vertigo, compared with the subgroup of remaining subjects with panic disorders with agoraphobia (p < 0.001).

CONCLUSIONS

Our data support the hypothesis that, in patients with panic disorders (and especially those with additional agoraphobia), dizziness may be linked to malfunction of the vestibular system. However, the data are not inconsistent with the hypothesis that migrainous vertigo is the most common pathophysiological mechanism for vestibular disorders.

Mal de debarquement

Mal de debarquement (MdD), the "sickness of disembarkment," occurs when habituation to background rhythmic movement becomes resistant to readaption to stable conditions and results in a phantom perception of self motion typically described as rocking, bobbing, or swaying. Although several studies have shown that brief periods of MdD are common in healthy individuals, this otherwise natural phenomenon can become persistent in some individuals and lead to severe balance problems. Increased recognition of MdD in a persistent pathological form occurred after the publication of a case series of six patients by Brown and Baloh in 1987. Over 20 years later, although more is known about the clinical syndrome of persistent MdD, little is known about what leads to this persistence. This review addresses the clinical features of MdD, the associated symptoms in the persistent form, theories on pathogenesis, experience with treatment, and future directions for research.

Dizziness: anxiety, health care utilization and health behavior--results from a representative German community survey

BACKGROUND

Due to the lack of epidemiological data on the relation of dizziness and anxiety, we investigated the prevalence of dizziness and anxiety in a representative sample of the German population. We explored the consequences of comorbid anxiety for emotional distress, functional impairment, health care utilization, and health behavior in dizziness.

METHODS

By the end of 2006, we surveyed a total of 1287 persons between 14 and 90 years of age in their homes by trained interviewers with standardized self-rating questionnaires on anxiety (Patient Health Questionnaire, Generalized Anxiety Disorder Scale, Mini-Social Phobia Inventory) and dizziness (Vertigo Symptom Scale). The sample was representative for the German population in terms of age, sex, and education.

RESULTS

Symptoms of dizziness were reported by 15.8% of the participants. Of the participants with dizziness, 28.3% reported symptoms of at least one anxiety disorder (generalized anxiety, social phobia, panic). Persons with dizziness reported more somatic problems such as hypertension, migraine, diabetes, etc. Comorbid anxiety was associated with increased health care use and impairment.

CONCLUSION

Dizziness is a highly prevalent symptom in the general population. A subgroup with comorbid anxiety is characterized by an increased subjective impairment and health care utilization due to their dizziness. Because treatment options for distinct neurotologic disorders are also known to reduce psychological symptoms, and in order to avoid unnecessary medical treatment, early neurologic and psychiatric/psychotherapeutic referral may be indicated.

Chronic subjective dizziness

CONCLUSION

Chronic subjective dizziness (CSD) is frequent and affects twice as many women as men. Anxiety is a strong predisposing factor. The pathophysiologic concept of this disorder assumes that balance function and emotion share common neurologic pathways, which might explain that the balance disorder can provoke fear and vice versa, giving rise to a problem in perception of space and motion. In anxious patients this can turn into a space and motion phobia, with avoidance behaviour.

OBJECTIVE

CSD is a diagnosis based on the hypothesis of an interaction between the vestibular system and the psychiatric sphere. Patients complain of chronic imbalance, worsened by visual motion stimulation, and frequently suffer from anxiety. Vestibular examination reveals no anomalies. We evaluated the incidence and characteristics of CSD in patients referred to our neuro-otology centre (tertiary hospital outpatient clinic).

SUBJECTS AND METHODS

This was a retrospective study of 1552 consecutive patients presenting with vertigo. CSD was diagnosed in 164 patients (female:male=111:53).

RESULTS

CSD represents 10.6% of the dizzy patients in our clinic. Psychiatric disorder, mainly anxiety, was found in 79.3% of the cases. Other frequently associated factors were fear of heights and former vestibular lesion (healed). In all, 79.0% of the patients with CSD had poor balance performance on dynamic posturography testing.

Effects of bilateral vestibular deafferentation on anxiety-related behaviours in Wistar rats

Despite frequent reports that patients with vestibular dysfunction exhibit an unusually high incidence of anxiety disorders, few studies have investigated the emotional effects of vestibular damage in animals. In this study we investigated the effects of a permanent surgical bilateral vestibular deafferentation (BVD) on the performance of rats in a series of anxiety tests at 3 weeks (3-W), 3 months (3-M) and 5 months (5-M) following the lesion. We used the elevated plus maze (EPM), elevated T maze (ETM), hyponeophagia and social interaction tests. Contrary to expectation, we found that, at 3 and 5M post-op, BVD rats spent more rather than less time on the open arms of the EPM compared to sham controls, and they displayed a lack of learned inhibitory avoidance in the ETM. Compared to sham controls, BVD rats showed no significant difference over the 3 time points in their latencies to eat in a novel situation; however, they did engage in social interaction to a significantly lesser extent. Finally, blood corticosterone levels were not significantly different between BVD and sham rats at 6 months post-op. These results suggest that BVD causes changes in the performance of rats in the EPM and ETM that might reflect emotional changes, or could be due to the cognitive impairment and hyperactivity caused by BVD.

Prevalence of vertigo, dizziness, and migrainous vertigo in patients with migraine

OBJECTIVE

The aim of this study was to determine the lifetime prevalence of vertigo and dizziness in patients with migraine as compared with controls and to establish the lifetime prevalence of migrainous vertigo.

BACKGROUND

Dizziness and vertigo are relatively frequent complaints in general population; however, the prevalence of migrainous vertigo has not been extensively studied so far.

METHODS

The study included 327 migraine patients and 324 controls who do not suffer from frequent headaches. The study and control group were assessed clinically and through diagnostic workup for having vertigo, dizziness, hypotension, and sideropenic anemia.

RESULTS

Vertigo or dizziness was experienced by 51.7% of migraine patients (MVL group) and 31.5% in the control group (CVL group), P < .0001. Among the MVL group, 23.2% of patients met the criteria for migrainous vertigo. There was no difference between the MVL group and CVL group in frequency of attacks or the pattern of symptom appearance in relation to head movement. Patients in the MVL group more frequently had hypotension, P = .011. Patients with migraine with aura significantly more often had migraine attacks in association with vertigo or dizziness, P < .0001.

CONCLUSION

The lifetime prevalence of migrainous vertigo is relatively frequent in migraine patients, especially in migraine with aura.

Otoneurological findings in human immunodeficiency virus positive patients

OBJECTIVE

To investigate vestibular function in human immunodeficiency virus positive subjects.

METHODS

We studied vestibular function in 60 human immunodeficiency virus positive subjects reporting dizziness. All three Center for Disease Control and Prevention categories of human immunodeficiency virus infection were represented in the study group (30 patients in class A, 20 in class B and 10 in class C). Subjects had had no previous history of acute vertigo. All subjects underwent: neurotological screening for spontaneous, positional and positioning nystagmus, using head-shaking and head-thrust (Halmagyi) tests; audiometrical examination; and electronystagmography with bithermal stimulation (Freyss' method). The results of the 30 class A subjects were compared with those of 30 human immunodeficiency virus negative patients reporting dizziness.

RESULTS

Abnormal otoneurological findings increased progressively from the A to C categories, particularly regarding increased central damage (3.3 per cent of class A, 35 per cent of class B and 100 per cent of class C subjects). In contrast, the incidence of peripheral vestibular disorders remained almost the same, comparing the three categories (33.3 per cent in class A and 50 per cent in classes B and C subjects). Moreover, a higher number of human immunodeficiency virus positive subjects showed abnormal otoneurological findings, compared with the dizzy, human immunodeficiency virus negative subjects.

CONCLUSIONS

In our opinion, a vestibular disorder may occur in human immunodeficiency virus positive patients as a result of direct viral damage, even in the early phase of infection. Central vestibular damage may be established later on, and may be linked to different causes (e.g. superinfections, vascular causes and drug toxicity).

Autonomic Nervous System Function in Chronic Dizziness

OBJECTIVE

The goals of this study were to validate the clinical diagnosis of autonomic dizziness as a cause of chronic nonvertiginous dizziness that may be exacerbated by physical exertion or orthostatic challenges, estimate its prevalence in a tertiary referral population, and investigate the usefulness of three autonomic challenges as objective tests for this condition.

STUDY DESIGN

Laboratory investigation of autonomic activity.

SETTING

Tertiary care balance center.

PATIENTS

Fifteen men and women with symptoms indicative of autonomic dizziness. Subjects with other causes of dizziness, histories of syncope, or psychiatric disorders were excluded.

INTERVENTIONS

Autonomic tests included 45 minutes of head upright tilt (HUT), 20 minutes of 5% CO2 inhalation and then HUT, and 2 minutes of voluntary hyperventilation and then HUT.

MAIN OUTCOME MEASURES

Patterns of cardiovascular and respiratory responses and subjective ratings of dizziness, autonomic symptoms, and anxiety during autonomic challenges.

RESULTS

Twelve subjects had evidence of autonomic dysfunction, including 10 with abnormal heart rate, blood pressure, or respiratory responses to HUT. Two other subjects had prolonged hypocarbia after voluntary hyperventilation. Many of these abnormalities would have been missed by current autonomic testing paradigms. In one subject, CO2 inhalation revealed latent anxiety. In two subjects, the presence of high symptom ratings without objective autonomic dysfunction prompted a successful search for other diagnoses.

CONCLUSION

Study results validated the clinical syndrome of autonomic dizziness. Autonomic testing protocols may have to be updated to detect clinically relevant abnormalities in patients with dizziness.

Anxiety and otovestibular disorders: linking behavioral phenotypes in men and mice

Human anxiety and vestibular disorders have long been known to co-occur. Paralleling human clinical and non-clinical data, mounting genetic, pharmacological and behavioral evidence confirms that animal anxiety interplays and co-exists with vestibular/balance deficits. However, relatively few animal models have addressed the nature of this relationship. This paper examines side-by-side human psychiatric and otovestibular phenotypes with animal experimentation data, and outlines future directions of translational research in this field. Discussed here are recently developed specific animal models targeting this interplay, other traditional animal tests sensitive to altered anxiety and vestibular domains, and the existing problems with translation of animal data into human phenotypes. The role of hearing deficits and their contribution to anxiety and vestibular phenotypes are also outlined. Overall, the overlap between anxiety and balance disorders emerges as an important phenomenon in both animal and clinical studies, and may contribute markedly to the complexity of behavioral and physiological phenotypes. Animal experimental models that focus on the interplay between anxiety and vestibular disorders are needed to improve our understanding of this important biomedical problem.