Space and motion discomfort and abnormal balance control in patients with anxiety disorders
- 1Department of Psychiatry, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
- 2Department of Otolaryngology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
- 3Department of Bioengineering, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
- Dr R G Jacob, Western Psychiatric Institute of the University of Pittsburgh Medical Center, Department of Psychiatry, 3811 O’Hara Street, Pittsburgh, PA 15213, USA; jacobr{at}upmc.edu
- Received 15 November 2007
- Revised 17 June 2008
- Accepted 19 June 2008
- Published Online First 24 July 2008
Abstract
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.
Footnotes
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Additional appendices are published online only at http://jnnp.bmj.com/content/vol80/issue1
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Presented in part at the 29th Midwinter Research Meeting of the Association for Research in Otolaryngology (ARO) Baltimore, Maryland, 6 February 2006, and at 41ème Symposium de la Société Internationale d’Otoneurologie, Paris, 18 May 2007.
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Competing interests: None.
