Temporal Course (Timing)
Temporal course includes information regarding the onset, duration, and frequency of symptoms. In general, dizziness lasting for less than 1 minute when the patient is lying down is associated with benign paroxysmal positional vertigo (BPPV), whereas dizziness lasting less than 1 minute when the patient stands up is associated with orthostatic hypotension (OH).
Note: Dizziness from BPPV can occur either with lying down, or with rising from the supine position. OH will only trigger dizziness when going from a down to an up position (lying to sitting, or sitting to standing). The duration of symptoms in these two conditions is often similar.
Distinct episodes or sudden onset of symptoms suggests peripheral disease, whereas gradual onset is indicative of a more central disorder (except cerebellar stroke). Patients with BPPV often incorrectly report constant dizziness over a period of hours to days. It is important to address these statements with further inquiry as to whether the vertigo was constant or experienced only when the patient moved his or her head during the specified time.
Many patients describe the duration of their symptoms as “quite a while” or “not too long.” These patients should be instructed to be specific by using seconds and minutes to describe the duration of symptoms.
Some patients will tell you they are “dizzy all the time.” This does not bode well for a meaningful discussion, as, in my experience, there is always some variation in symptoms based on time, movement, position change, etc. Of course, the exception to this comment is when you see a patient while still in the acute phase of a vertiginous episode, for example, vestibular neuritis. They truly can be “dizzy all the time” for a few days. From an examiners viewpoint, these patients are fairly easy to spot without an extensive and accurate history because their clinic signs are typically obvious.
Next week we look at “Triggers” which includes precipitating, exacerbating and relieving factors.