Among patients I see with Panic Disorder, a striking number have symptoms in specific situations. Persons with Panic Disorder have spontaneous attacks of intense fear and discomfort that begin abruptly, almost like an adrenaline rush or flight or fight reaction, like palpitations, sweating, shaking, intense fear, tremor, inability to catch one’s breath. These sensations occur on spontaneously or when in specific situations such as a car or supermarket. Sensitivity to a car or market is so typical, it bolsters the diagnosis of a panic attack. Whenever I suspect panic disorder, I always ask specifically about reactions to being in a car or supermarket. Most of the time the person will mention it on their own. It is enough to make you wonder what’s so unusual about these particular situations?

I used to think that markets and automobiles engendered so much fear because you can't readily escape these situations and feel trapped, but a number of patients have told me this is not so. What seems to happen is that in both circumstances you are having to deal with bodies moving toward or away from you in a narrow passageway. You are expected to make numerous split-second decisions (computations) about moving objects if you plan to avoid a mishap or accident and you have to depend on vision alone. For most of us this is second nature and we have no problem. When we walk around a supermarket balance and walking come to us automatically. A lot of this mediated by vestibular and proprioceptive systems.

The supermarket or highway may disproportionately affect persons who have subtle abnormalities with vestibular or proprioceptive systems. Under such conditions a person may become visually dependent. He or she depends abnormally on visual systems in order to stand, walk, and maintain balance. Now if you ask them to go into a supermarket and begin to try to avoid obstacles and moving persons and to shop at the same time, their visual computation apparatus goes into overload and anxiety occurs. The theory then, about why anxiety attacks are so common under specific circumstances, is that in some patients at least, there may be a vestibular component to anxiety disorders. You’re asking their visual systems to do too much. The frequent occurrence in relation to these specific stimuli may also explain why panic disorder is so frequent now in the age of fast moving cars on freeways and elaborate supermarkets, as opposed to previous times, when anxiety and neurosis expressed itself in its own special circumstances.

I’m not trying to say here that anxiety or panic disorders are caused by vestibular dysfunction. If that were the case, persons with inner ear disease and the aged would all have panic disorder. Instead what seems to happen is that persons who have a certain tendency to have panic disorder, and I’m not prepared to discuss here what makes some persons have this tendency, may find they become symptomatic under specific circumstances that tax the computation capacity of their visual systems. This explains some characteristics of panic disorder and may even play into the common symptom of agoraphobia, fear of going out into strange places. Subjects may simply not wish avoid overloading their brainstem computers. If we can put our finger on this aspect of panic attack disorder, it is possible we may be able to intervene in some cases with vestibular training and rehabilitation. More than that, panic and anxiety disorders may be thought of as physical syndromes i.e. disorders of sensory systems rather than psychiatric symptoms of unknown etiology.

Visual dependence and computational overload may explain dysfunction in a number of other situations. Persons who are afraid of heights (acrophobia) also overuse their eyes. Watch one sometime. The eyes are wide open and they are looking around and down while normal folks walk about hardly using their eyes, confident they won't fall even at the edge of a cliff or atop a mountain. Acrophobics don’t have this confidence and are overly dependent on their eyes. Acrophobics try to use their eyes in a conscious effort to maintain balance while walking continues to be automatic for normals. With visual systems overwhelmed, anxiety is compounded. Makes you wonder whether persons with a fear of height might benefit from vestibular retraining as well.

Let’s suppose you become for one reason or another, be it anxiety or malfunction of vestibular or proprioceptive systems, overly dependent on vision. Then most of the time complicating the visual field by adding even more stimuli will worsen the situation. An interesting case in point is the Parkinson patient with gait and balance disorder. Parkinson’s is a motor disease in which exact motor computations are impaired by a defect in the basal ganglia. Frequently the Parkinsonian festinates, takes tiny steps, and is unable to account for a shift in his center of gravity. Unable to make rapid motor defensive adjustments to environmental perturbations, he falls. He will falter unless he is constantly vigilant, conscious, about his gait and balance, whereas for most normals, this is entirely of second nature.

What do you observe? Most of the time the severe Parkinson patient will fall or freeze, if you complicate visual input by adding more stimuli. If another person suddenly appears in the room, or he has to walk through a turnstile or a doorway, he’ll get overwhelmed festinate, take tiny steps, and topple over. All of this is extraneous noise that overwhelms him. But certain limited visual stimuli will help the Parkinson patient to walk. Paint or tape equidistant lines on the floor, and he will miraculously begin to make perfect strides and will not fall over!! From this we learn that there are two classes of sensory stimuli for patients who are impaired or visually dependent. There is noise, impairing stimuli and likewise there is a smaller category of guidance sensory stimuli.

About the worst thing you can do to an acrophobic is to put him on a high ski slope. The guy will be stuck on the top of the hill scared to death on his skis. Now place him in the middle of the slope with lots of skiers swooshing down the slopes past him. Maybe place another drop on to the right of him, and make him go down a narrow passageway. He’ll be scared to death.

Is their anything you can do to help? The best thing is to expose the acrophobic to vestibular and proprioceptive training before you send him to the slopes. Reduce visual dependence. The most rational approach to anxiety disorders (at least in some cases) would be to unload overburdened sensory systems as much as possible. Teach the subject to use alternative systems (vestibular, proprioceptive) and reduce sensory overload. Alternatively provide guidance sensory stimuli; avoid noise. Vestibular rehab may have a role in treating some forms of anxiety.

The foregoing describes how the vestibular system may interact with anxiety mechanisms. I’ve often heard new mothers observe that their toddler can’t walk yet only because they are afraid. Toddler’s don’t get up on their own and step because of fear. Spouses of Parkinson patients frequently make the same observation. It’s only the fear of walking that’s stopping them. Fear of walking, nine times out of ten, is well-founded. Toddlers and Parkinsonians are afraid of walking because their at risk of falling. The fear of losing one’s balance is a deeply entrenched protective mechanism.

The same very likely is connected with the frequent co-existence of anxiety and dizziness. Anxious persons are frequently dizzy. In a good many instances a person who sees a doctor because of dizziness, anxiety is the primary problem. Some of these have so-called "phobic postural vertigo". There is good evidence from other quarters that these folks have pervasive anxiety. What we don't know and have difficulty measuring and defining, is the component of vestibular dysfunction and the relative roles of psychiatric and physical problem.

There is little doubt that dizziness can occur from anxiety alone. This dizziness tends to be vaguely described or more often it is a light-headedness or giddiness, rarely a discreet vertigo. A dysequalibrium or gait unsteadiness rarely happens just form anxiety although a complaint of sudden weakness of the knees is often encountered. A trial of hyperventilation is used to exacerbate dizziness suspected of coming from anxiety. If dizziness happens after hyperventilation, it's always considered to be strong evidence for a psychological cause. However there are some vestibular conditions where hyperventilation will temporarily increase vertigo. Accurate apportionment of symptoms to psychological vs. Physical or vestibular cause can be very complicated. In order to do so we may have to break old rules.