Patients with BPPV, regardless of initial treatment option rendered, will have variable responses to therapy (Cohen, et al., 2005). The response to therapy may depend on several factors including the accuracy of the diagnosis of BPPV, the duration of symptoms prior to the diagnosis of BPPV, compliance with prescribed therapy, and other factors (Hilton, et al., 2004) (Rupa, et al., 2004). Patients with BPPV should be reassessed within a set time interval after the diagnosis of BPPV for several reasons.

Failure to respond to initial therapy may indicate an initially erroneous diagnosis of BPPV, and one of the major goals of reassessment is to ensure the accuracy of diagnosis of BPPV. As noted, other more serious CNS disorders may mimic BPPV, and these conditions would not be expected to respond to traditional therapies prescribed for BPPV. In cohort studies, the rate of false-positive diagnosis for BPPV subsequently found to be CNS lesions after failed treatment (therefore, a highly selected population) with PRM ranges from 1.1 to 3 percent (Rupa, et al., 2004) (Dal, et al., 2000). Thus, persistence of symptoms after initial management requires clinicians to reassess and reevaluate patients for other etiologies of vertigo. Conversely, resolution of BPPV symptoms after initial therapy such as a PRM would corroborate an accurate diagnosis of BPPV.

Patients who are initially treated with vestibular rehabilitation may fail to resolve symptoms owing to multiple factors including poor compliance. In addition, patients who do not respond to initial therapy are likely to remain at risk for falls, decreased quality of life, and other consequences of unresolved BPPV. For these reasons, patients whose symptoms of BPPV fail to resolve should also be identified and classified as initial treatment failures. To define a treatment failure in BPPV, the clinician needs to determine both a failed outcome criterion and an appropriate time interval for assessment of treatment failure. Successful treatment outcomes for interventions for BPPV are traditionally measured in clinical trials by subjective symptom resolution and/or by conversion to a negative Dix-Hallpike test. Almost all treatment trials for BPPV report an outcome measure in the form of the patient’s reported symptoms, typically reported among three categorical outcomes: complete resolution of symptoms, improvement, or no improvement/worsening (Hilton, 2004). When included in meta-analyses, treatment responses are typically incorporated as “all or none” for the complete resolution of vertigo (Hilton, et al., 2004) (Woodworth, et al., 2004) (Teixeira, et al., 2006).

Because effective treatment options are available for BPPV that typically render patients symptom free (if treatment is successful), it is logical to use complete symptom resolution as the outcome of choice at the time of reassessment by the clinician. A symptom-based reassessment also allows clinicians to use clinical judgment as to the most appropriate modality for follow-up for individual patients, including telephone communication, electronic communication, or office based reexamination. This symptom-based assessment of treatment resolution should be detailed enough to distinguish patients with truly decreased symptoms related to treatment or patients with minimized symptoms attributable to positional avoidance (who, in fact, may not be treatment successes) from those with true symptom resolution (Woodworth, et al., 2004).

Although conversion to a negative Dix-Hallpike test may have the advantage of being a more objective reassessment than patients’ reported symptoms, it also carries the disadvantage of requiring a repeat clinical visit on the part of the patient with associated direct and indirect costs. The Dix- Hallpike test status is commonly reported in therapeutic trials of BPPV. Persistent symptoms of BPPV and other underlying conditions, however, have been reported in the face of negative Dix-Hallpike testing after therapy, potentially making this a less sensitive reassessment tool (Lynn, et al., 1995) (Magliulo, et al., 2005).

Conversely, patients may report an absence of symptoms after therapeutic intervention yet still have a positive Dix-Hallpike test (Cohen, et al., 2005) (Froehling, et al., 2000) (Sherman, et al., 2001). “Subclinical BPPV” has been offered as an explanation for this (Cohen, et al., 2005). Because of the potential discordance between negative Dix-Hallpike conversion and patients’ reported symptoms after treatment for BPPV, Dix- Hallpike conversion is not recommended as the primary reassessment criterion in routine clinical practice but may still be used as a secondary outcome measure. There is no widely accepted time interval at which to assess patients for treatment failure. Therapeutic trials in BPPV variably report follow-up assessments for treatment outcomes at 40 hours, 2 weeks, 1 month, and up to 6 months, although the most commonly chosen interval for follow-up assessment of treatment response is within or at 1 month (Hilton, et al., 2004) (Woodworth, et al., 2004) (Teixeira, et al., 2006). Because the natural history of BPPV exhibits a relatively consistent spontaneous rate of resolution with observation alone, a longer time interval between diagnosis and reassessment would allow patients with true BPPV to resolve symptoms spontaneously, likely irrespective of treatment (Sekine, et al., 2006).

Conversely, the choice of an excessively long time interval between diagnosis and reassessment would also allow cases of an erroneous BPPV diagnosis to potentially progress, leading to potential patient harm. In addition, because recurrence of BPPV may occur as early as 3 months after initial treatment, further delaying the time interval for reassessment may erroneously incorporate a recurrent BPPV syndrome (ie, the initial BPPV responded to treatment with a suitable symptom-free interval thereafter, followed by recurrent BPPV) rather than a persistent BPPV syndrome (Nunez, et al., 2000) (Helminski, et al., 2005).

Given that commonly reported rates of spontaneous complete symptom resolution at the 1-month interval for BPPV range from 20 to 80 percent at 1 month, reassessment at 1 month will also better allow for patients to be reconsidered for further interventional treatment to treat unresolved BPPV (Froehling, et al., 2000) (Lynn, et al., 1995) (Yimtae, et al., 2003) (Munoz, et al., 2007) (Sekine, et al., 2006) (von Brevern, et al., 2006). Thus, choosing a reassessment time interval of 1 month after diagnosis allows a relative balance between overly early reassessment (which would force the unnecessary reassessment of patients who would likely resolve with additional time) and unduly delayed reassessment (which would potentially allow harm from an unknown missed diagnosis or relegate patients to an excess time interval of symptomatic suffering from BPPV). One potential problem with a strict time interval for reassessment is that patients may not have been exposed to their initial treatment (vestibular rehabilitation or PRM as opposed to observation, which may begin immediately after diagnosis) within 1 month of diagnosis depending on referral patterns, patient preferences, or waiting lists for specialty evaluation and treatment. This situation is especially true when the diagnosing clinician may not be the same as the treating clinician. Even if a delay occurs between BPPV diagnosis and completion of the initial treatment, clinicians should still reassess patients at 1 month but may choose to reassign a second time interval for reassessment after completion of the initial treatment option.