Panic disorder: the role of the balance system

Post-stroke dizziness, depression and anxiety

OBJECTIVE

Vestibular and psychiatric disorders are very closely related. Previous research shows that the discomfort and dysfunction caused by dizziness in patients can affect psychological processes, leading to anxiety and depression, and the irritation of anxiety and depression can aggravate the discomfort of dizziness. But the causal relationship between dizziness in the recovery period of stroke and Post-stroke depression (PSD) / Post-stroke anxiety (PSA) is not clear. Identifying the causal relationship between them can enable us to conduct more targeted treatments.

METHODS

We review the epidemiology and relationship of dizziness, anxiety, and depression, along with the related neuroanatomical basis. We also review the pathophysiology of dizziness after stroke, vestibular function of patients experiencing dizziness, and the causes and mechanisms of PSD and PSA. We attempt to explore the possible relationship between post-stroke dizziness and PSD and PSA.

CONCLUSION

The treatment approach for post-stroke dizziness depends on its underlying cause. If the dizziness is a result of PSD and PSA, addressing these psychological factors may alleviate the dizziness. This can be achieved through targeted treatments for PSD and PSA, such as psychotherapy, antidepressants, or anxiolytics, which could indirectly improve dizziness symptoms. Conversely, if PSA and PSD are secondary to vestibular dysfunction caused by stroke, a thorough vestibular function assessment is crucial. Identifying the extent of vestibular impairment allows for tailored interventions. These could include vestibular rehabilitation therapy and medication aimed at vestibular restoration. By improving vestibular function, secondary symptoms like anxiety and depression may also be mitigated.

Balance Rehabilitation with Peripheral Visual Stimulation in Patients with Panic Disorder and Agoraphobia: An Open-Pilot Intervention Study

Given the involvement of balance system abnormalities in the pathophysiology of panic disorder and agoraphobia (PD-AG), we evaluated initial evidence for feasibility, acceptability, and potential clinical usefulness of 10 sessions of balance rehabilitation with peripheral visual stimulation (BR-PVS) in an open-pilot 5-week intervention study including six outpatients with PD-AG who presented residual agoraphobia after selective serotonin reuptake inhibitor (SSRI) treatment and cognitive-behavioral therapy, dizziness in daily life, and peripheral visual hypersensitivity measured by posturography. Before and after BR-PVS, patients underwent posturography, otovestibular examination (no patients presented peripheral vestibular abnormalities), and panic-agoraphobic symptom and dizziness evaluation with psychometric tools. After BR-PVS, four patients achieved postural control normalization measured by posturography, and one patient exhibited a favorable trend of improvement. Overall, panic-agoraphobic symptoms and dizziness decreased, even though to a lesser extent in one patient who had not completed the rehabilitation sessions. The study presented reasonable levels of feasibility and acceptability. These findings suggest that balance evaluation should be considered in patients with PD-AGO presenting residual agoraphobia and that BR-PVS might be an adjunctive therapeutic option worth being tested in larger randomized controlled studies.

Motor alterations in depression and anxiety disorders: A systematic review and meta-analysis

BACKGROUND

Psychomotor retardation has long been recognized as a major feature of depression, and anxiety disorders have been linked with freeze and flight motor responses. This systematic review and meta-analysis aimed a) to synthesize available evidence of motor alterations comparing individuals with depression and anxiety disorders to healthy individuals and b) to evaluate the effect of experimental manipulations of motor displays within these clinical groups.

METHOD

The databases PubMed and PsycINFO were searched for studies either assessing motor differences between clinical and healthy control groups or manipulating the motor system within a clinical group.

RESULTS

The literature search yielded 87 relevant papers, comprising 82 studies comparing a clinical group to a healthy group and 5 studies investigating motor manipulations within a clinical sample. The results of the meta-analysis (K = 71) indicated a statistically significant combined estimate of differences between healthy and clinical groups (g = 0.38 [0.31, 0.45], adjusted for publication bias g = 0.26 [0.19, 0.33]) of a small size. This effect did not vary according to type of disorder (anxiety vs. depression, p = .468). From a narrative review of experimental studies within clinical groups, four out of five studies reported statistically significant effects of manipulating the motor system on affective outcomes.

DISCUSSION

This synthesis adds to the accumulating empirical evidence of motor alterations in depression and anxiety disorders. Future research will need to investigate how individuals suffering from depression or anxiety disorders could benefit from psychological, behavioral, and physical interventions directly aimed at the motor system.

Responses to balance challenges in persons with panic disorder: A pilot study of computerized static and dynamic balance measurements

INTRODUCTION

Several studies have shown an association between panic disorder (PD) and reduced balance abilities, mainly based on functional balance scales. This pilot study aims to demonstrate the feasibility of studying balance abilities of persons with PD (PwPD) using computerized static and, for the first time, dynamic balance measurements in order to characterize balance control strategies employed by PwPD.

METHODS

Twelve PwPD and 11 healthy controls were recruited. PD diagnosis was confirmed using the Diagnostic and Statistical Manual of Mental Disorders, fourth edition (DSM-IV), and the severity of symptoms was evaluated using the Hamilton Anxiety Scale (HAM-A), PD Severity Scales (PDSS), and Panic and Agoraphobia Scale (PAS). Balance was clinically assessed using the Activities-Specific Balance Confidence (ABC) scale and physically by the Mini-Balance Evaluation Systems Test (Mini-BESTest). Dizziness was evaluated using the Dizziness Handicap Inventory (DHI) scale. Postural control was evaluated statically by measuring body sway and dynamically by measuring body responses to rapid unexpected physical perturbations.

RESULTS

PwPD had higher scores on the HAM-A (17.6 ± 10.3 vs. 3.0 ± 2.9; p < .001), PDSS (11.3 ± 5.1 vs. 0; p < .001), and PAS (20.3 ± 8.7 vs. 0; p < .001) questionnaires and lower scores on the balance scales compared to the controls (ABC scale: 156.2 ± 5.9 vs. 160 ± 0.0, p = .016; Mini-BESTest: 29.4 ± 2.1 vs. 31.4 ± 0.9, p = .014; DHI: 5.3 ± 4.4 vs. 0.09 ± 0.3, p < .001). In the static balance tests, PwPD showed a not-significantly smaller ellipse area of center of pressure trajectory (p = .36) and higher body sway velocity (p = .46), whereas in the dynamic balance tests, PwPD had shorter recovery time from physical perturbations in comparison to controls (2.1 ± 1.2s vs. 1.6 ± 0.9 s, p = .018).

CONCLUSION

The computerized balance tests results point to an adoption of a ''postural rigidity'' strategy by the PwPD, that is, reduced dynamic adaptations in the face of postural challenges. This may reflect a nonsecure compensatory behavior. Further research is needed to delineate this strategy.

Correlation between anxiety and chronic motion sensitivity

BACKGROUND

Chronic motion sensitivity (CMS) is a combination of autonomic symptoms provoked by exposure to motion. The correlation between anxiety and CMS is not yet well understood.

OBJECTIVES

1) To compare median anxiety levels between young adults with and without CMS. 2) To examine the effect of anxiety on postural stability with immersion virtual reality. 3) To compare anxiety levels between sexes.

METHODS

Participants included 60 adults (20-40 years), with and without CMS. After determining their current and general anxiety levels, postural stability was measured.

RESULTS

There were significant differences in median (minimum, maximum) state- and trait-anxiety scores between participants with and without CMS, but no significant differences in median state- and trait-anxiety scores between males and females with CMS. There was a significant inverse relationship between state- and trait-anxiety scores and postural stability (ρ= -0.28, p = 0.03, and ρ= -0.32, p = 0.01, respectively). The stepwise regression analysis showed the Motion Sickness Susceptibility Questionnaire-Short Form score to be the only variable contributing significantly to postural stability (R2 = 26.2%; t = -4.5, p <  0.001).

CONCLUSIONS

Young adults with CMS are more anxious, although anxiety does not contribute to postural stability in this group. Anxiety levels do not appear to differ between young adult males and females with CMS.

Impaired Attentional Processing During Parabolic Flight

Previous studies suggest that altered gravity levels during parabolic flight maneuvers affect spatial updating. Little is known about the impact of the experimental setting and psychological stressors associated with parabolic flight experiments on attentional processes. To address this gap, we investigated the level of alertness, selective and sustained attention in 1 and 0 g using a Go/No-Go Continuous Performance Task. We also identified several parameters associated with the experimental set-up of a parabolic flight that could be expected to affect attentional processing. These included the use of scopolamine, sleep quality prior to the flight day, participant’s stress level as well as mood and anxiety state before and after the parabolic flight. We observed a deterioration in attentional processing prior to the first parabola that was further aggravated in weightlessness and returned to baseline after the last parabola. Reaction Time, Hit and False Alarm Rate were moderately correlated with self-reported anxiety state, but not cortisol levels or emotional states. The use of scopolamine had minor effects on Reaction Time. Our results confirm previous studies reporting impairments of cognitive performance in 0 g, and highlight important aspects that should be considered for the design of behavioral research experiments in future parabolic flight campaigns.

Episodic Spontaneous Dizziness

PURPOSE OF REVIEW

Conditions causing recurrent spontaneous episodes of dizziness or vertigo span several medical specialties, making it challenging for clinicians to gain confidence in evaluating and managing the spectrum of episodic vestibular disorders. Patients are often asymptomatic and have normal examinations at the time of evaluation. Thus, diagnosis depends heavily on eliciting key features from the history. Overreliance on symptom quality descriptions commonly leads to misdiagnosis. The goal of this article is to provide the reader with a straightforward approach to the diagnosis and management of conditions that cause episodic spontaneous dizziness.

RECENT FINDINGS

Consensus diagnostic criteria have been established for vestibular migraine, Ménière disease, vestibular paroxysmia, and hemodynamic orthostatic dizziness/vertigo. Vertigo has been recognized as a common symptom in vertebrobasilar ischemia, cardiogenic dizziness, and orthostatic hypotension. Treatment recommendations for vestibular migraine still lack high-quality evidence, but controlled trials are occurring.

SUMMARY

The evaluation should start with a detailed description of the episodes from the patient and any observers. Rather than focusing first on whether the symptom quality is most consistent with vertigo, dizziness, lightheadedness, or unsteadiness, the clinician should clarify the timing (episode frequency and duration), possible triggers or circumstances (eg, position changes, upright posture), and accompanying symptoms. History should identify any auditory symptoms, migraine features, posterior circulation ischemic symptoms, vascular risk factors, clues for anxiety, and potentially relevant medications. Carefully selected testing can help secure the diagnosis, but excessive and indiscriminate testing can lead to more confusion. Treatments for these conditions are vastly different, so an accurate diagnosis is critical.

Movement and Emotional Facial Expressions during the Adult Attachment Interview: Interaction Effects of Attachment and Anxiety Disorder

INTRODUCTION

Adult attachment is commonly associated with emotion regulation. Less is known about the nonverbal embodiment of adult attachment.

OBJECTIVE

We hypothesized that dismissing attachment is related to less movement and fewer facial expressions of emotions, whereas preoccupied attachment is associated with more negative emotional facial expressions. Moreover, the interaction of attachment and the presence of an anxiety disorder (AD) was explored.

METHODS

The sample included 95 individuals, 21 with AD without comorbidity, 21 with AD and comorbid major depression (AD-CD), and 53 healthy controls. We analyzed nonverbal behavior during a part of the Adult Attachment Interview (AAI) asking about the family and parental figures. The movements of the interviewees were captured via Motion Energy Analysis. Facial expressions were coded according to the Facial Action Coding System using the OpenFace software. We compared individuals with secure, dismissing, and preoccupied states of mind (assessed with the AAI) with regard to the frequency and complexity of movements and the frequency of the facial expressions such as happy, sad, and contemptuous.

RESULTS

As expected, dismissingly attached individuals moved less often and with lower complexity than securely attached. For emotional facial expressions, a main effect of the disorder group and interaction effects of attachment by disorder were found. In the AD-CD group, dismissingly attached patients showed comparatively fewer happy facial expressions than securely attached individuals.

CONCLUSIONS

Reduced movement specifically seems to be related to dismissing attachment when interviewees talk about significant parental figures. Facial expressions of emotions related to attachment occurred when maladaptive emotion regulation strategies were intensified by a psychological disorder.

Effects of acquired vestibular pathology on the organization of mouse exploratory behavior

Rodent open field behavior is highly organized and occurs spontaneously in novel environments. This organization is disrupted in mice with vestibular pathology, suggesting vestibular signals provide important contributions to this behavior. A caveat to this interpretation is that previous studies have investigated open field behavior in adult mice with congenital vestibular dysfunction, and the observed deficits may have resulted from developmental changes instead of the lack of vestibular signals. To determine which aspects of open field behavior depend specifically on vestibular signals, mouse movement organization was examined under dark and light conditions at two time points, 1 and 2 months, after bilateral chemical labyrinthectomy. Our results show that acquired vestibular damage selectively disrupted the organization of open field behavior. Access to visual environmental cues attenuated, but did not eliminate, these significant group differences. Improvement in movement organization from the first to the second testing session was limited to progression path circuity. These observations provide evidence for the role of the vestibular system in maintaining spatial orientation and establishes a foundation to investigate neuroplasticity in brain systems that process self-movement information.

Lower Functional Connectivity in Vestibular-Limbic Networks in Individuals With Subclinical Agoraphobia

Background: Agoraphobia was described in 1871 as a condition of fear-related alterations in spatial orientation and locomotor control triggered by places or situations that might cause a patient to panic and feel trapped. In contemporary nosology, however, this original concept of agoraphobia was split into two diagnostic entities, i.e., the modern anxiety disorder of agoraphobia, consisting solely of phobic/avoidant symptoms in public spaces, and the recently defined vestibular disorder of persistent postural perceptual dizziness (PPPD), characterized by dizziness, and unsteadiness exacerbated by visual motion stimuli. Previous neuroimaging studies found altered brain activity and connectivity in visual-vestibular networks of patients with PPPD vs. healthy controls. Neuroticism and introversion, which pre-dispose to both agoraphobia and PPPD, influenced brain responses to vestibular and visual motion stimuli in patients with PPPD. Similar neuroimaging studies have not been undertaken in patients with agoraphobia in its current definition. Given their shared history and pre-disposing factors, we sought to test the hypotheses that individuals with agoraphobic symptoms have alterations in visual-vestibular networks similar to those of patients with PPPD, and that these alterations are influenced by neuroticism and introversion. Methods: Drawing from the Human Connectome Project (HCP) database, we matched 52 participants with sub-clinical agoraphobia and 52 control subjects without agoraphobic symptoms on 19 demographic and psychological/psychiatric variables. We then employed a graph-theoretical framework to compare resting-state functional magnetic resonance images between groups and evaluated the interactive effects of neuroticism and introversion on the brain signatures of agoraphobia. Results: Individuals with subclinical agoraphobia had lower global clustering, efficiency and transitivity relative to controls. They also had lower connectivity metrics in two brain networks, one positioned to process incoming visual space-motion information, assess threat, and initiate/inhibit behavioral responses (visuospatial-emotional network) and one positioned to control and monitor locomotion (vestibular-navigational network). Introversion interacted with agoraphobic symptoms to lower the connectivity of the visuospatial-emotional network. This contrasted with previous findings describing neuroticism-associated higher connectivity in a narrower visual-spatial-frontal network in patients with PPPD. Conclusion: Functional connectivity was lower in two brain networks in subclinical agoraphobia as compared to healthy controls. These networks integrate visual vestibular and emotional response to guide movement in space.

Toward a personalized therapy for panic disorder: preliminary considerations from a work in progress

Although several treatment options for panic disorder (PD) are available, the best intervention for each individual patient remains uncertain and the use of a more personalized therapeutic approach in PD is required. In clinical practice, clinicians combine general scientific information and personal experience in the decision-making process to choose a tailored treatment for each patient. In this sense, clinicians already use a somehow personalized medicine strategy. However, the influence of their interpretative personal models may lead to bias related to personal convictions, not sufficiently grounded on scientific evidence. Hence, an effort to give some advice based on the science of personalized medicine could have positive effects on clinicians' decisions. Based on a narrative review of meta-analyses, systematic reviews, and experimental studies, we proposed a first-step attempt of evidence-based personalized therapy for PD. We focused on some phenomenological profiles, encompassing symptoms during/outside panic attacks, related patterns of physiological functions, and some aspects of physical health, which might be worth considering when developing treatment plans for patients with PD. We considered respiratory, cardiac, vestibular, and derealization/depersonalization profiles, with related implications for treatment. Given the extensiveness of the topic, we considered only medications and some somatic interventions. Our proposal should be considered neither exhaustive nor conclusive, as it is meant as a very preliminary step toward a future, robust evidence-based personalized therapy for PD. Clearly much more work is needed to achieve this goal, and recent technological advances, such as wearable devices, big data platforms, and the application of machine learning techniques, may help obtain reliable findings. We believe that combining the efforts of different research groups in this work in progress can lead to largely shared conclusions in the near future.

Are there advances in pharmacotherapy for panic disorder? A systematic review of the past five years

INTRODUCTION

Several effective medications are available for treating panic disorder (PD). However, outcomes are unsatisfactory in a number of patients, suggesting the usefulness of expanding the array of antipanic drugs and improving the quality of response to current recommended treatments.

AREAS COVERED

The authors have performed an updated systematic review of pharmacological studies (phase III onwards) to examine whether advances have been made in the last five years. Only four studies were included. D-cycloserine no longer seemed promising as a cognitive-behavioral therapy (CBT) enhancer. Some preliminary findings concerning the optimization of recommended medications deserved consideration, including: the possibility that SSRIs are more effective than CBT alone in treating panic attacks, combined therapy is preferable when agoraphobia is present, and clonazepam is more potent than paroxetine in decreasing panic relapse.

EXPERT OPINION

Given the lack of novel treatments, expanding a personalized approach to the existing medications seems to be the most feasible strategy to improve pharmacotherapy outcomes regarding PD. Recent technological progress, including wearable devices collecting real-time data, 'big data' platforms, and application of machine learning techniques might help make outcome prediction more reliable. Further research on previously promising novel treatments is also recommended.

Is panic disorder a disorder of physical fitness? A heuristic proposal

Currently, panic disorder (PD) is considered a mental disorder based on the assumptions that panic attacks (PAs) are “false alarms” that arise from abnormally sensitive defense systems in the central nervous system and that PD is treated with therapies specifically acting on anxiety or fear mechanisms. This article aims to propose an alternative perspective based on the results of some experimental studies. Our heuristic proposal suggests not only that PD may be a mental disorder but also that patients with PD have real abnormal body functioning, mainly involving cardiorespiratory and balance systems, leading to a decline in global physical fitness. PAs, as well as physical symptoms or discomfort in some environmental situations, may be “real alarms” signaling that the adaptability resources of an organism are insufficient to respond appropriately to some internal or external changes, thus representing the transient conscious awareness of an imbalance in body functioning. The antipanic properties of several modern treatments for PD may include their beneficial effects on body functions. Although anxiety or fear mechanisms are evidently involved in PD, we hypothesize that a reduction of physical fitness is the “primum movens” of PD, while anxiety or fear is induced and sustained by repeated signals of impaired body functioning. We propose considering panic in a broader perspective that offers a central role to the body and to contemplate the possible role of somatic treatments in PD.

Exploring the relationship between threat-related changes in anxiety, attention focus, and postural control

Individuals report directing attention toward and away from multiple sources when standing under height-related postural threat, and these changes in attention focus are associated with postural control modifications. As it is unknown whether these changes generalize to other types of threat situations, this study aimed to quantify changes in attention focus and examine their relationship with postural control changes in response to a direct threat to stability. Eighty young adults stood on a force plate fixed to a translating platform. Three postural threat conditions were created by altering the expectation of, and prior experience with, a postural perturbation: no threat of perturbation, threat without perturbation experience, and threat with perturbation experience. When threatened, participants were more anxious and reported directing more attention to movement processes, threat-related stimuli, and self-regulatory strategies, and less to task-irrelevant information. Postural sway amplitude and frequency increased with threat, with greater increases in frequency and smaller increases in amplitude observed with experience. Without experience, threat-related changes in postural control were accounted for by changes in anxiety; larger changes in anxiety were related to larger changes in sway amplitude. With experience, threat-related postural control changes were accounted for by changes in attention focus; increases in attention to movement processes were related to greater forward leaning and increases in sway amplitude, while increases in attention to self-regulatory strategies were related to greater increases in sway frequency. Results suggest that relationships between threat-related changes in anxiety, attention focus, and postural control depend on the context associated with the threat.

Management of Treatment-Resistant Panic Disorder

PURPOSE OF REVIEW

Purpose of Review Management of treatment-resistant (TR) panic disorder (PD) is an unresolved issue. In this paper, we provide a brief summary of previous findings, an updated (2015-2017) systematic review of pharmacological/non-pharmacological studies, and our personal perspective on this topic.

RECENT FINDINGS

Recent Findings We found a very limited number of recent findings. Quetiapine extended-release augmentation has not been found to be beneficial, in comparison to placebo, in non-responders to previously recommended pharmacotherapy. In non-responders to cognitive behavioral therapy (CBT), switching to paroxetine/citalopram has been found to be more effective than continuing CBT. Acceptance and commitment therapy (ACT) has shown some improvement in patients' resistance to previous psychological/pharmacological interventions compared with a waiting-list condition.

SUMMARY

Summary Previous and recent findings regarding the treatment of TR PD suffer from several methodological limitations. Available studies provide insufficient evidence to support the use of medications alternative to the recommended medications; the efficacy of ACT needs confirmation with more rigorous methodology. Prolonged pharmacotherapy may produce significant improvement in patients with unsatisfactory response to short-term pharmacotherapy, while switching to pharmacotherapy may help non-responders to CBT. We discuss our personal perspective on the definition of "treatment resistance" as it relates to PD and provide personalized intervention strategies to increase favorable clinical outcomes based on our clinical expertise and review of experimental studies on the pathophysiology of PD.

Posturographic destabilization in eating disorders in female patients exposed to body image related phobic stimuli

Human postural control is dependent on the central integration of vestibular, visual and proprioceptive inputs. Psychological states can affect balance control: anxiety, in particular, has been shown to influence balance mediated by visual stimuli. We hypothesized that patients with eating disorders would show postural destabilization when exposed to their image in a mirror and to the image of a fashion model representing their body ideal in comparison to body neutral stimuli. Seventeen females patients attending a day centre for the treatment of eating disorders were administered psychometric measures of body dissatisfaction, anxiety, depression and underwent posturographic measures with their eyes closed, open, watching a neutral stimulus, while exposed to a full length mirror and to an image of a fashion model corresponding to their body image. Results were compared to those obtained by eighteen healthy subjects. Eating disordered patients showed higher levels of body dissatisfaction and higher postural destabilization than controls, but this was limited to the conditions in which they were exposed to their mirror image or a fashion model image. Postural destabilization under these conditions correlated with measures of body dissatisfaction. In eating disordered patients, body related stimuli seem to act as phobic stimuli in the posturographic paradigm used. If confirmed, this has the potential to be developed for diagnostic and therapeutic purposes.

Personality traits and individual differences predict threat-induced changes in postural control

This study explored whether specific personality traits and individual differences could predict changes in postural control when presented with a height-induced postural threat. Eighty-two healthy young adults completed questionnaires to assess trait anxiety, trait movement reinvestment (conscious motor processing, movement self-consciousness), physical risk-taking, and previous experience with height-related activities. Tests of static (quiet standing) and anticipatory (rise to toes) postural control were completed under low and high postural threat conditions. Personality traits and individual differences significantly predicted height-induced changes in static, but not anticipatory postural control. Individuals less prone to taking physical risks were more likely to lean further away from the platform edge and sway at higher frequencies and smaller amplitudes. Individuals more prone to conscious motor processing were more likely to lean further away from the platform edge and sway at larger amplitudes. Individuals more self-conscious about their movement appearance were more likely to sway at smaller amplitudes. Evidence is also provided that relationships between physical risk-taking and changes in static postural control are mediated through changes in fear of falling and physiological arousal. Results from this study may have indirect implications for balance assessment and treatment; however, further work exploring these factors in patient populations is necessary.

Visuo-vestibular contributions to anxiety and fear

The interactive roles of the visual and vestibular systems allow for postural control within boundaries of perceived safety. In specific circumstances, visual vestibular and postural interactions act as a cue that trigger fear, similarly to what occurs in motion sickness. Unusual patterns of visuo-vestibular interaction that emerge without warning can elicit fear, which can then become associated to a certain stimuli or situation, creating a CS-US association, (i.e., phobia), or can emerge without warning but also without becoming associated to a particular concomitant event (i.e., panic). Depending on the individual sensitivity to visuo-vestibular unusual patterns and its impact in postural control, individuals will be more or less vulnerable to develop these disorders. As such, the mechanism we here propose is also sufficient to explain the lack of certain fears albeit exposure. Following this rationale, a new subcategory of anxiety disorders, named visuo-vestibular fears can be considered. This model brings important implications for developmental and evolutionary psychological science, and invites to place visuo-vestibular fears in a particular subtype or specification within the DSM-5 diagnostic criteria.

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.

Stress response and humoral immune system alterations related to chronic hypergravity in mice

Spaceflights are known to induce stress and immune dysregulation. Centrifugation, as hindlimb unloading, is a good ground based-model to simulate altered gravity which occurs during space missions. The aim of this study was to investigate the consequences of a long-term exposure to different levels of hypergravity on the stress response and the humoral immunity in a mouse model. For this purpose, adult C57Bl/6J male mice were subjected for 21 days either to control conditions or to 2G or 3G acceleration gravity forces. Corticosterone level and anxiety behavior revealed a stress response which was associated with a decrease of body weight, after 21-day of centrifugation at 3G but not at 2G. Spleen lymphocyte lipopolysaccharide (LPS) responsiveness was diminished by 40% in the 2G group only, whereas a decrease was noted when cells were stimulated with concanavalin A for both 2G and 3G groups (about 25% and 20%, respectively) compared to controls. Pro-inflammatory chemokines (MCP-1 and IP-10) and Th1 cytokines (IFNγ and IL2) were slightly decreased in the 2G group and strongly decreased in the 3G mouse group. Regarding Th2 cytokines (IL4, IL5) no further significant modification was observed, whereas the immunosuppressive cytokine IL10 was slightly increased in the 3G mice. Finally, serum IgG concentration was twice higher whereas IgA concentration was slightly increased (about 30%) and IgM were unchanged in 2G mice compared to controls. No difference was observed in the 3G group with these isotypes. Consequently, functional immune dysregulations and stress responses were dependent of the gravity level.

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.

[Validation of the French version of the situational characteristics questionnaire in the measurement of space and motion discomfort]

INTRODUCTION

Space and motion discomfort (SMD) refers to various symptoms that occur in environments with unreliable visual and kinesthetic information that do not permit adequate spatial orientation. Some studies have demonstrated that there is a stable and predictable relationship between vestibular dysfunction and anxiety disorders. Further, vestibular dysfunction can predispose or trigger the development of panic disorder with or without agoraphobia (PD/A) or reinforce phobic avoidance. It therefore seems clinically useful to develop and validate instruments for evaluating SMD in various populations. Measuring SMD could facilitate identification of individuals with PD/A who present comorbid vestibular dysfunction. Jacob et al. developed and validated such a questionnaire: the Situational characteristics questionnaire (SitQ). This questionnaire evaluates the presence of symptoms such as dizziness, vertigo, and instability under specific conditions. The SitQ comprises two subscales that measure SMD and one subscale (agoraphobia) that measures agoraphobic avoidance behaviours. The instrument has two sections. The first section is composed of the SMD-I and agoraphobia subscales, containing 19 and seven items, respectively. Each item consists of two contrasting descriptors of a specific situation or environment. The respondent is required to indicate to what extent the two described situations or environments cause discomfort. Each item includes a "criterion" descriptor for the situation (i.e., a descriptor that is presumed to engender SMD) and an alternative (non-criterion) descriptor. The second section comprises the SMD-II scale; this scale is composed of nine criterion situations, for which non-criterion situations are not supplied. The instrument takes approximately 20 minutes to complete.

OBJECTIVE

The present study focuses on the validation of the French-language version of the SitQ: the questionnaire des caractéristiques situationnelles (QCS).

METHOD

The sample was composed of French Canadians recruited across Quebec from an anxiety disorders treatment clinic, general psychiatric care clinics, a community organization for individuals with anxiety disorders, advertisements in local newspapers, and ads posted in various public locations. The sample included 141 participants who met the criteria for lifetime PD/A. Participants reported current PD/A (n=73) or PD/A in remission (n=68). The control sample was recruited from undergraduate courses in various disciplines. Two hundred and thirty-five (n=235) students completed the questionnaires. Data from 63 (26.8%) participants were excluded from the analyses due to failure to complete all of the research questionnaires.

RESULTS

Analysis of the global descriptive data and the descriptive data for each dependent variable revealed that the data were independent of sociodemographic variables and respected the assumptions of normal distribution (skewness and kurtosis). Parametric tests were subsequently conducted. Using the combined data from the control and clinical groups, the internal consistency of the scales was analyzed using Cronbach's alpha. The SMD-I and SMD-II scales demonstrated good homogeneity. The results were comparable or superior to those obtained with the English-language version of the questionnaire. The agoraphobia scale demonstrated weaker internal consistency and corresponding weaker homogeneity. This result was consistent with that of the original version of the agoraphobia scale; this scale was eliminated for the subsequent analyses. Construct validity was analyzed via t-tests comparing clinical and control groups. Effect sizes were estimated using percentage of variance explained. The SMD-I scale demonstrated weak construct validity and was also eliminated from subsequent analyses. The SMD-II scale demonstrated good construct validity and provided an adequate measure of the theoretical construct of SMD. This scale permitted discrimination of participants according to the presence or absence of PD/A. It is therefore possible to identify participants with PD/A by their level of SMD. This result is comparable to that of Jacob et al.

CONCLUSION

The results of the present study are generally consistent with the results of the validation of the original version of the questionnaire. However, the SMD-I and agoraphobia scales in the French-language version of the measure did not achieve a level of significance sufficient to definitively establish validity.

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.

Relevance of orthostatic posturography for clinical evaluation of hip and knee joint arthroplasty patients

In order to verify whether orthostatic posturography (OP) can support clinical assessment of total hip (THA) and knee arthroplasty (TKA), 81 subjects with THA and 100 with TKA were recruited and compared with 59 healthy volunteers. All patients were tested one or two days prior to surgery; 42 subjects (20 THA and 22 TKA) were tested again after six months, and 34 (14 THA and 20 TKA) yet again after 12 months. OP was performed using a Kistler 9286A piezoelectric force plate and the following postural parameters (PPs) were adopted on account of their functional meaning: mean velocity and the root mean square of the distance of the centre of pressure (CoP), sway area, and 95% of the CoP power frequency. Eye condition and fatigue related to the test duration were also examined. The three most meaningful PPs were identified and a logarithmic transformation was then applied to these, as well as standardization. Almost all the PP values were higher preoperatively in the patients as compared with the healthy subjects and it was possible to detect many statistically significant differences between patients and healthy subjects. However, when examining the 181 subjects at the preoperative stage, the PPs did not show congruence with the clinical scores as well as they did during follow-up. Therefore, the use of the OP is not recommended to monitor patients undergoing THA or TKA.

Cost-effectiveness analysis of an occupational therapy-led lifestyle approach and routine general practitioner's care for panic disorder

OBJECTIVE

To assess the cost-effectiveness of an occupational therapy-led lifestyle approach to treating panic disorder in primary care compared with routine general practitioner's (GP) care. The burden of mental health disorders is considerable. Cost-effective interventions are necessary to alleviate some of these burdens. Habitual lifestyle behaviours influence mood, although to date mainly single lifestyle factor trials have been conducted to examine the effects on anxiety.

METHODS

An economic evaluation was conducted alongside an unblinded pragmatic randomised controlled trial with assessment at 5 and 10 months. Costs and consequences, as measured by the Beck anxiety inventory (BAI) and quality adjusted life years (QALYs), were compared using incremental cost-effectiveness ratios (ICERs).

RESULTS

The occupational therapy-led lifestyle intervention was more costly than routine GP care at both 5 and 10 months. Significant outcome improvements were evident at 5 months when using the BAI, although these were not maintained at 10 months. Small differences in mean QALYs were found. The estimated ICER was 36 pounds per BAI improvement for 5 months and 39 pounds for 10 months, and 18,905 pounds per QALY gained for 5 months and 8,283 pounds for 10 months.

CONCLUSIONS

If the maximum willingness to pay per additional QALY is 30,000 pounds, then there is an 86% chance that a lifestyle intervention may be considered to be value-for-money over 10 months.

Balance control in quiet upright standing in patients with panic disorder

The postural stability of 30 panic disorder (PD) patients and 30 sex- and age-matched healthy control subjects (age range 27-40 years) was investigated by static posturographic tests of quiet standing on stable and foam surfaces with open and closed eyes. Postural stability was evaluated by sway velocity (SV) and power density of relative power spectrum (RPS) in five frequency ranges. There were no differences of SV between two groups during stance with open eyes on both surfaces. The SV of the PD patients standing with closed eyes was significantly higher compared to controls for the stance on the stable surface (anterior-posterior plane) and on the foam surface (both anterior-posterior and medial-lateral planes). The stance on foam surface did not cause any significant changes in power density of postural sways of healthy subjects, while this parameter was significantly higher for PD patients, especially in closed eyes condition when a sensory conflict may exist. The higher value of SV and RPS (0.5-1.0 Hz) in patients compared to controls suggests that the visual information has more important role in the postural balance when sensory conflict exists during stance on foam surface. We proposed that the altered information from the visual and proprioceptive inputs may induce anxiety and panic symptoms in PD patients, which enhances the sensory conflict, leads to abnormal work of the vestibular system and disturbs the standing balance.

Subtypes of panic attacks: a critical review of the empirical literature

BACKGROUND

Panic disorder is a heterogeneous disorder, comprising a variety of somatic, physiological, and cognitive symptoms during repeated panic attacks. As a result, considerable data have examined whether panic attacks may be classified into distinct diagnostic or functional subtypes. The aim of this study is to evaluate the existing literature regarding the validity of panic attack subtypes.

METHODS

This review focuses on data published since 2000, with the publication of DSM-IV-TR, augmented by replicated data published since 1980, with the publication of DSM-III and subsequently DSM-IV. Published reports evaluating empirical evidence for the validity of panic attack subtypes are reviewed.

RESULTS

Five sets of panic symptoms (respiratory, nocturnal, nonfearful, cognitive, and vestibular) have been shown to cluster together at varying degrees of consistency. However, none of these potential subtypes have been associated with sufficient and reliable external validation criteria indicative of functional differences. This apparent lack of findings may be related to methodological inconsistencies or limitations across the reviewed studies.

CONCLUSIONS

Although at present the data do not warrant the utility of subtyping, further research aimed at patent gaps in the literature, including clearer operationalization of symptom subtypes, greater use of biological challenge paradigms and physiological and other more objective measures of fear and anxiety, and exploration of subtyping based on biological factors such as genetics, may support the future designation of panic attack subtypes and their ultimate clinical utility.

Space and motion discomfort and abnormal balance control in patients with anxiety disorders

OBJECTIVE

Previous research suggested that panic disorder with agoraphobia is associated with abnormalities on vestibular and balance function tests. The purpose of this study was to further examine psychiatric correlates of vestibular/balance dysfunction in patients with anxiety disorders and the specific nature of the correlated vestibular abnormalities. The psychiatric variables considered included anxiety disorder versus normal control status, panic disorder versus non-panic anxiety disorder diagnosis, presence or absence of comorbid fear of heights, and degree of space and motion discomfort (SMD). The role of anxiety responses to vestibular testing was also re-examined.

METHODS

104 subjects were recruited: 29 psychiatrically normal individuals and 75 psychiatric patients with anxiety disorders. Anxiety patients were assigned to four subgroups depending on whether or not they had panic disorder and comorbid fear of heights. SMD and anxiety responses were measured by questionnaires. Subjects were examined for abnormal unilateral vestibular hypofunction on caloric testing indicative of peripheral vestibular dysfunction, asymmetric responses on rotational testing as an indicator of an ongoing vestibular imbalance and balance function using Equitest dynamic posturography as an indicator of balance control. Logistic regression was used to establish the association between the psychiatric variables and vestibular or balance test abnormalities.

RESULTS

Rotational test results were not significantly related to any of the psychiatric variables. The presence of either panic attacks or fear of heights increased the probability of having caloric hypofunction in a non-additive fashion. SMD and anxiety responses were independently associated with abnormal balance. Among specific posturography conditions, the association with SMD was significant for a condition that involved the balance platform tilting codirectionally with body sway, suggesting an abnormal dependence on somatosensory cues in the control of balance.

CONCLUSION

In patients with anxiety disorders, higher SMD is indicative of somatosensory dependence in the control of balance. The absence of both panic and fear of heights reduces the probability of having peripheral vestibular dysfunction. Future research should examine if vestibular rehabilitation can be of value for patients with anxiety disorders complicated by SMD.

Influences of lifestyle and general practice (GP) care on the symptom profile of people with panic disorder

Current treatment guidelines for anxiety disorders, including panic disorder (PD), recommend either medication or cognitive behavioural therapy (CBT). There is currently a call through the Layard Report for significant investment to increase the availability of CBT resources. However, there are reported limitations to both medication and CBT in the treatment of anxiety, and it appears prudent to consider additional methods of treatment that may offer effective interventions. One such intervention is based around the evidence of altered sensitivity within a number of physiological body systems in anxiety patients (particularly those with PD), all of which are influenced in their function by habitual lifestyle behaviours. A randomised controlled trial compared a 16‐week occupational therapy‐led lifestyle intervention and routine general practice (GP) care for PD. At 20 weeks, 14 symptoms with ‘moderate’ to ‘very severe’ ratings were assessed in 36 GP and 31 lifestyle‐intervention patients. Composite symptom profiles, similar at baseline, were produced. The GP intervention produced modest improvements in most symptoms. The lifestyle intervention overall produced greater symptomatic relief (Wilcoxon signed ranks test, P= 0.008). The physiological and cognitive symptom profile also changed more with lifestyle intervention. Occupational therapists have developed their interventions based on their understanding of everyday occupation. Habitual lifestyle behaviours are characterised as being recurrent elements of everyday occupation and are, therefore, legitimate targets for occupational therapy interventions. They provide a vehicle through which to encourage patients to regain understanding and control of their own anxiety symptoms.

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.

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.

A pragmatic, unblinded randomised controlled trial comparing an occupational therapy-led lifestyle approach and routine GP care for panic disorder treatment in primary care

BACKGROUND

Treated anxiety increased in the UK by over 30% since 1994. Medication and psychological treatment is most common, but outcomes are sometimes poor, with high relapse rates. Lifestyle has a potential role in treatment, but is not considered in clinical guidelines. Panic disorder is potentially influenced by lifestyle factors.

METHODS

16 week unblinded pragmatic randomised controlled trial in 15 East of England primary care practices (2 Primary Care Trusts). Participants met DSM-IV criteria for panic disorder with/without agoraphobia. Follow-up at 20 weeks and 10 months. Control arm, unrestricted routine GP care. Trial Arm, Occupational therapy-led lifestyle treatment comprising: lifestyle review of fluid intake, diet pattern, exercise, caffeine, alcohol and nicotine; negotiation of positive lifestyle changes; monitoring and review of impact of changes.

PRIMARY OUTCOME MEASURE

Beck Anxiety Inventory.

DATA ANALYSIS

Intention-to-treat analysis provided between-group comparisons using analysis of co-variance. Bonferroni method to adjust p-values.

RESULTS

From 199 referrals, 36 GP care and 31 lifestyle arm patients completed to final follow-up. Significantly lower lifestyle arm BAI scores at 20 weeks (p<0.001), non-significant (p=0.167) at 10 months after Bonferroni correction. 63.6% lifestyle arm, and 40% GP arm patients (p=0.045) panic-free at 20 weeks; 67.7% and 48.5% (p=0.123) respectively at 10 months.

LIMITATIONS

Final study size/power calls for caution in interpreting findings.

CONCLUSIONS

A lifestyle approach may provide a clinically effective intervention at least as effective as routine GP care, with significant improvements in anxiety compared with routine GP care at the end of treatment. Further study is required before suggesting practice changes.

Visually induced postural sway in anxiety disorders

Postural sensitivity to moving visual environments in patients with anxiety disorders was studied. We hypothesized that patients with anxiety disorders would have greater sway in response to a moving visual environment compared to healthy adults, especially if they have space and motion discomfort (SMD). Twenty-one patients with generalized anxiety without panic (NPA) and 38 patients with panic and agoraphobia (PAG) were compared to 22 healthy controls. SMD was evaluated in all subjects via questionnaire. Subjects stood on a force platform that was either fixed or rotating with the subject (i.e., sway referenced) during exposure to a sinusoidally moving visual surround. Center of pressure (COP) data were computed from force transducers in the platform as a measure of sway. Results showed that patients swayed significantly more in response to the moving visual scene compared to control subjects, with no differences between the NPA and PAG groups. SMD was a predictor of sway response in the patients: patients with high SMD swayed significantly more than both Controls and anxiety patients with low SMD. These results indicate that patients with anxiety disorders, particularly those with SMD, are more visually dependent for balance. This subgroup of patients may be amenable to treatment used for patients with balance disorders (i.e., vestibular rehabilitation) that focuses on sensory re-integration processes that address visual sensitivity.

Posturographic stabilisation of healthy subjects exposed to full-length mirror image is inversely related to body-image preoccupations

Affective states, anxiety in particular, have been shown to negatively influence human postural control efficiency as measured by posturographic means, while exposure to a full-length mirror image of one's body exerts a stabilizing effect. We tested the hypothesis that body image concerns and preoccupations would relate negatively to this stabilising effect. Sixty-six healthy students, who screened negative for psychiatric disorders, completed rating scales for anxiety, depression and body image concerns. Posturography recordings of body sway were taken under three conditions: with eyes closed, looking at a vertical bar and looking at a full-length mirror. The Eyes Open/Mirror Stabilometric Quotient [EOMQ=(sway path with eyes closed/sway path looking at the mirror)x100], an index of how much postural control is stabilized by mirror feedback in comparison to the visual vertical bar condition, was significantly inversely related to body image concerns and preoccupations, and to trait anxiety. This finding confirms the impact of emotional factors on human postural control, which warrant further studies. If confirmed in clinical populations characterized by high levels of body image disturbances, e.g. eating disorders, it could lead to developments in the assessment and monitoring of these patients.

Antidepressants and dizziness

Despite several evidences supporting a close relationship between dizziness and anxiety symptoms, the role of antidepressants in the treatment of such conditions remains poorly explored. The high prevalence of dizziness during serotonin reuptake inhibitors discontinuation syndrome and the few reports suggesting efficacy of antidepressants in treating some vestibular disorders justify a careful investigation. Neurophysiologic studies suggest possible focus of investigation on mechanisms of drug action. Psychophysiologic studies also suggest a possible role of antidepressant drugs in improving balance control and cognitive functioning. Controlled studies involving antidepressants with selective action in different neurotransmitters systems are necessary to elucidate the complex pathophysiologic mechanisms involving emotional and balance control. For future researches, special attention must be paid to the methodology of balance evaluation and the interaction between posture control and cognitive functioning.

Treatment of phobic postural vertigo

In balance clinic practice, phobic postural vertigo is a term used to define a population with dizziness and avoidance behavior often as a consequence of a vestibular disorder. It has been described as the most common form of dizziness in middle aged patients in dizziness units. Anxiety disorders are common among patients with vestibular disorders. Cognitive-behavioral therapy is an effective treatment for anxiety disorders, and vestibular rehabilitation exercises are effective for vestibular disorders. This study compared the effect of additional cognitive-behavioral therapy for a population with phobic postural vertigo with the effect of self-administered vestibular rehabilitation exercises. 39 patients were recruited from a population referred for otoneurological investigation. Treatment effects were evaluated with the Dizziness Handicap Inventory, Vertigo Symptom Scale, Vertigo Handicap Questionnaire, and Hospital Anxiety and Depression Scale. All patients had a self treatment intervention based on education about the condition and recommendation of self exposure by vestibular rehabilitation exercises. Every second patient included was offered additional cognitive behavioral therapy. Fifteen patients with self treatment and 16 patients with cognitive- behavioral treatment completed the study. There was significantly larger effect in the group who received cognitive behavioral therapy than in the self treatment group in Vertigo Handicap Questionnaire and the Hospital Anxiety and Depression scale and its subscales. Cognitive-behavioral therapy has an additional effect as treatment for a population with phobic postural vertigo. A multidisciplinary approach including medical treatment, cognitive-behavioral therapy and physiotherapy is suggested.

Standing balance in persistent whiplash: a comparison between subjects with and without dizziness

OBJECTIVE

Dizziness and unsteadiness, associated with altered balance, are frequent complaints in subjects suffering persistent whiplash associated disorders. Research has been inconclusive with respect to possible aetiology. This study assessed balance responses in subjects with whiplash associated disorders, taking into account several possible causes.

DESIGN

A prospective, 3 group, observational design.

SUBJECTS

100 subjects with persistent whiplash associated disorders, 50 complaining of dizziness, 50 not complaining of dizziness and 50 healthy controls.

METHODS

The Clinical Test for Sensory Interaction in Balance was performed in both comfortable and tandem stance. The sway trace was analysed using wavelet analysis.

CONCLUSION

The results indicated that the energy of the sway signal for comfortable stance tests was significantly greater in the group with dizziness compared with the group without dizziness. In the group without dizziness the energy was greater than controls for all tests, but significantly different on selected tests. In selected tandem stance tests, subjects with dizziness were significantly less able to complete the test than subjects without dizziness and controls. These deficits could not be attributed to medications, compensation, anxiety or age and are likely to be due to disturbances to the postural control system possibly originating from abnormal cervical afferent input.

Effect of mood state on anticipatory postural adjustments

Static postural control has been demonstrated to link with psychological state. However, the effect of psychological state on dynamic postural control remains unclear. In this study, we examined the effect of mood state on anticipatory postural adjustment (APA), one of the most important functions for dynamic postural control. Fourteen healthy male subjects performed unilateral arm elevation tasks after completing a Profile of Mood States (POMS) questionnaire. Mood state measured by POMS and the latency or amplitude of the APA in the ventral muscles (rectus femoris, tibialis anterior) of the lower limb showed significant negative correlations. The correlation between the mood state and APA amplitude in the soleus was found to be significantly positive. There were significant negative correlations between the mood state and reaction-time. These findings suggest that it is possible that dynamic postural control is affected by mood state.

Audiovestibular functioning in patients with panic disorder

OBJECTIVE

The objective of this study was to investigate audiovestibular function in patients with panic disorder and healthy subjects by using vestibular and audiologic tests.

METHODS

Thirty-four panic disorder patients and 20 healthy control subjects were assessed by using clinical otoneurological examination, pure tone audiometry, tympanometry, and electronystagmography (ENG). All patients were evaluated with the Panic and Agoraphobia Scale (PAS), the Hamilton Anxiety Rating Scale (HARS), the Hamilton Depression Rating Scale (HDRS), and the State-Trait Anxiety Inventory (STAI).

RESULTS

On vestibular testing, abnormal responses were more prevalent in panic disorder patients compared to healthy controls. The presence of agoraphobia in panic disorder patients did not make a significant difference on vestibular test results. The only variable that may be a predictor of vestibular abnormalities in panic disorder patients was found to be dizziness between attacks.

CONCLUSION

The results show that dizziness between panic attacks may warrant audiovestibular testing among other medical investigations.

Panic disorder: from respiration to the homeostatic brain

There is some experimental evidence to support the existence of a connection between panic and respiration. However, only recent studies investigating the complexity of respiratory physiology have revealed consistent irregularities in respiratory pattern, suggesting that these abnormalities might be a vulnerability factor to panic attacks. The source of the high irregularity observed, together with unpleasant respiratory sensations in patients with panic disorder (PD), is still unclear and different underlying mechanisms might be hypothesized. It could be the result of compensatory responses to abnormal respiratory inputs or an intrinsic deranged activity in the brainstem network shaping the respiratory rhythm. Moreover, since basic physiological functions in the organism are strictly interrelated, with reciprocal modulations and abnormalities in cardiac and balance system function having been described in PD, the respiratory findings might arise from perturbations of these other basic systems or a more general dysfunction of the homeostatic brain. Phylogenetically ancient brain circuits process physiological perceptions/sensations linked to homeostatic functions, such as respiration, and the parabrachial nucleus might filter and integrate interoceptive information from the basic homeostatic functions. These physiological processes take place continuously and subconsciously and only occasionally do they pervade the conscious awareness as 'primal emotions'. Panic attacks could be the expression of primal emotion arising from an abnormal modulation of the respiratory/homeostatic functions.

Serotonergic modulation of the balance system in panic disorder: an open study

Experimental evidence suggests that panic disorder is characterized by abnormalities in the balance system function and that these abnormalities might be related to the severity of agoraphobic avoidance. Since the balance system can be modulated by the serotonergic system, we investigated the effect of a 6-week treatment with citalopram on the balance system function in patients with panic disorder. Fifteen patients with panic disorder with/without agoraphobia underwent static posturography on days 0 and 42. Static posturography and clinical assessments were carried out by different investigators who were blind to each other. Static posturography showed high percentages of abnormal scores. Patients with no or low agoraphobic avoidance showed less abnormal posturographic measures than those with moderate to severe agoraphobia. After 6 weeks of treatment with citalopram there was a significant decrease of four out of six posturography measures in eyes-closed and neck extension conditions, whereas no significant effect was found in the eyes-open condition. This is the first report that suggests that the modulation of the serotonergic system can improve the balance system function in patients with panic disorder, particularly when visual information is lacking. In addition, our findings confirm the observation that many patients with panic disorder have abnormalities in their balance system function, supporting the idea that these abnormalities are mainly related to agoraphobic avoidance.

Evidence for vestibular regulation of autonomic functions in a mouse genetic model

Physiological responses to changes in the gravitational field and body position, as well as symptoms of patients with anxiety-related disorders, have indicated an interrelationship between vestibular function and stress responses. However, the relative significance of cochlear and vestibular information in autonomic regulation remains unresolved because of the difficulties in distinguishing the relative contributions of other proprioceptive and interoceptive inputs, including vagal and somatic information. To investigate the role of cochlear and vestibular function in central and physiological responses, we have examined the effects of increased gravity in wild-type mice and mice lacking the POU homeodomain transcription factor Brn-3.1 (Brn-3bPou4f3). The only known phenotype of the Brn-3.1(-/-) mouse is related to hearing and balance functions, owing to the failure of cochlear and vestibular hair cells to differentiate properly. Here, we show that normal physiological responses to increased gravity (2G exposure), such as a dramatic drop in body temperature and concomitant circadian adjustment, were completely absent in Brn-3.1(-/-) mice. In line with the lack of autonomic responses, the massive increase in neuronal activity after 2G exposure normally detected in wild-type mice was virtually abolished in Brn-3.1(-/-) mice. Our results suggest that cochlear and vestibular hair cells are the primary regulators of autonomic responses to altered gravity and provide genetic evidence that these cells are sufficient to alter neural activity in regions involved in autonomic and neuroendocrine control.

Vestibular information is required for dead reckoning in the rat

Dead reckoning is an on-line form of spatial navigation used by an animal to identify its present location and return directly to a starting location, even after circuitous outward trips. At present, it is not known which of several self-movement cues (efferent copy from movement commands, proprioceptive information, sensory flow, or vestibular information) are used to compute homeward trajectories. To determine whether vestibular information is important for dead reckoning, the impact of chemical labyrinthectomy was evaluated in a test that demanded on-line computation of a homeward trajectory. Rats were habituated to leave a refuge that was visible from all locations on a circular table to forage for large food pellets, which they carried back to the refuge to eat. Two different probe trials were given: (1) the rats foraged from the same spatial location from a hidden refuge in the light and so were able to use visual cues to navigate; (2) the same procedure took place in the dark, constraining the animals to dead reckon. Although control rats carried food directly and rapidly back to the refuge on both probes, the rats with vestibular lesions were able to do so on the hidden refuge but not on the dark probe. The scores of vestibular reflex tests predicted the dead reckoning deficit. The vestibular animals were also impaired in learning a new piloting task. This is the first unambiguous demonstration that vestibular information is used in dead reckoning and also contributes to piloting.