The differential diagnosis for positional dizziness/vertigo, such as vertigo upon waking up or standing up, includes benign paroxysmal positional vertigo (BPPV), orthostatic hypotension (OH), autonomic dysfunction, and so on. A correct and efficient diagnosis of this condition is important. The purposes of this study were to clarify in which cases is a Schellong test the optimal means of diagnosing OH among patients with positional vertigo and to obtain specific answers to our original questionnaire on dizziness/vertigo among OH patients. All the patients who visited our office complaining of dizziness/vertigo between 2012 and 2015 were asked to perform the Schellong test and to complete our questionnaire. We used a conventional BPPV diagnostic maneuver to diagnosis BPPV. The results were analyzed statistically. A total of 309 cases returned analyzable questionnaire results. Overall, 38 cases were finally diagnosed as having certain BPPV based on the observation of positional nystagmus; 104 cases tested positive using the Schellong test. None of the items in the questionnaire were correlated with either a positive or negative Schellong test result. When 13 Schellong test-positive cases were excluded from the certain BPPV group, three answers to the questions in the questionnaire differed significantly between the certain BPPV group and the Schellong test-positive group. These answers were as follows: a waking up/lying down movement or rolling over in a supine position triggers vertigo, and a specific head position exacerbates vertigo. In conclusion, when a patient complains of vertigo upon waking up or standing up, the following two specific questions should be asked: “Is your vertigo triggered by waking up/lying down or by rolling over in a supine position?” and “Does a specific head position exacerbate your vertigo?” If a patient answers ‘yes’ to either of these questions and positional nystagmus is not observed, a Schellong test should be performed to diagnose OH.
