Detailed evaluation of many patients who have a chronic perception of dizziness not related to vertigo reveals underlying psychiatric or neurologic disease, according to an article in the February issue of Archives of Otolaryngology---Head & Neck Surgery.

This particular type of chronic dizziness not related to vertigo has long eluded understanding by treating physicians, according to background information in the article. Some researchers have proposed the term chronic subjective dizziness for this condition.

"Patients with this syndrome have chronic nonspecific dizziness, subjective imbalance and hypersensitivity to motion stimuli, which are exacerbated in complex visual environments (namely, walking in a busy store, driving in the rain)," the authors wrote.

Jeffrey P. Staab, MD, and colleagues at the University of Pennsylvania Health System, Philadelphia, studied 345 men and women age 15 to 89 years (average, 43.5 years) who had dizziness for three months or longer due to unknown causes. From 1998 to 2004, the patients were tracked from their referral to a balance center through multiple specialty examinations until they were given a diagnosis.

All but six patients were diagnosed as having psychiatric or neurologic conditions, including primary or secondary anxiety disorders, migraine, traumatic brain injury and neurally mediated dysautonomias, or abnormal functioning of the autonomic nervous system.

Anxiety disorders were associated with 60 percent of chronic dizziness cases and central nervous system conditions (including migraine, brain injuries and autonomic nervous system disorders) with 38.6 percent. Six patients (1.7 percent) had cardiac arrhythmia.

"The results of this investigation provide some insight into pathophysiologic mechanisms that may precipitate and perpetuate chronic dizziness," the authors wrote. "Two thirds of patients had medical conditions associated with the onset of dizziness, whereas one third had anxiety disorders as the initial cause. Therefore, chronic subjective dizziness may be triggered by either neurotologic [ear-related] or psychiatric conditions."