**5.6 Dynamic visual acuity test (DVAT)**

The Dynamic Visual Acuity Test (DVAT) provides an instrumented, objective, behavioral assessment of vestibulo-ocular reflex (VOR) function in response to rotational or functional head movement stimuli by determining the smallest optotype an individual can identify during both dynamic and static conditions. One option to perform the DVAT is applying the Snellen Chart (**Figure 6**) combined with a metronome or other systems [28].

**Figure 4.** *COBALT courtesy: Bertec.*

**Figure 5.** *Vestibular/ocular motor screen.*

#### **Figure 6.** *Snellen chart.*

It is also available in computerized systems. In this case, the patient is solicited to recognize the direction of the middle arm of the optotype while continuing either an active or passive head movement at a fixed velocity. According to the modification (increase or decrease) in the target size or optotype, established on the successes or failures on each trial until a final acuity is defined [29].

The test has been reported to have good reliability in healthy athletes however has not consistently demonstrated the ability to discern between those with and without a concussion. Further research is necessary to consider the clinical utility for SRC [28–30].
