The Vision, Aphasia, Neglect (VAN) assessment is a streamlined, rapid screening tool used in pre-hospital and emergency department settings for patients presenting with acute stroke symptoms. Its purpose is to quickly identify individuals with a high likelihood of a Large Vessel Occlusion (LVO) stroke, caused by a blockage in a major artery of the brain. The presence of an LVO suggests the patient may be a candidate for endovascular thrombectomy, a specialized procedure to mechanically remove the clot. Using the VAN assessment helps medical teams efficiently triage patients, ensuring those who may benefit from this time-sensitive intervention are directed to the appropriate stroke center without delay.
Context and Preparation for the VAN Assessment
The VAN assessment is an adjunct tool performed only after an initial, general stroke screening test, such as the Cincinnati Prehospital Stroke Scale (CPSS) or FAST, is positive. Before proceeding to the V, A, and N components, a specific motor weakness assessment must be performed. The patient is asked to hold both arms out straight for ten seconds to check for arm drift or inability to lift one arm.
This initial motor assessment acts as a gateway. If the patient shows no unilateral arm weakness, they are considered negative for the type of LVO the VAN screen is designed to detect, and the rest of the assessment is halted. The presence of any drift or paralysis triggers the continuation of the VAN protocol. The individual must be sufficiently alert and able to follow basic instructions, as the assessment relies on patient cooperation.
Clear communication with the patient is important before beginning the neurological checks. The entire process is designed to be quick and reproducible, helping to rapidly mobilize resources and expedite the patient’s journey to definitive treatment. The VAN assessment serves as a focused, time-saving filter for LVO, not a replacement for a full neurological examination.
Executing the Core Components: Vision and Aphasia
The first component, Vision (V), focuses on detecting visual field defects, which are common with LVO strokes. To assess vision, the examiner performs a confrontation test, asking the patient to look straight ahead at the examiner’s nose. The examiner then tests all four visual quadrants by bringing their fingers into the patient’s field of view and asking the patient to identify them.
An abnormal finding, or “V positive,” is noted if the patient has a visual field cut (hemianopia), new onset blindness, or new double vision. The examiner should also check for forced gaze deviation, where the eyes are involuntarily turned toward one side and the patient cannot track movement across the midline.
The second component, Aphasia (A), evaluates the patient’s language function, which is often impaired in dominant hemisphere strokes. Aphasia is assessed by testing three key areas: comprehension, expression, and repetition. To check comprehension, simple commands are given, such as “close your eyes” or “make a fist,” and the patient’s ability to follow them is observed.
Expressive language is tested by having the patient repeat a simple phrase and asking them to name two common objects, like a pen or a watch. If the patient has difficulty producing language (expressive aphasia) or struggles to understand commands (receptive aphasia), the “A” component is marked as positive. It is important to distinguish true aphasia from dysarthria (slurred speech due to muscle weakness).
Neglect Assessment and Clinical Interpretation
The final component, Neglect (N), assesses for hemispatial neglect. This is a failure to report, respond, or orient to stimuli on the side opposite the brain lesion, most commonly the left side. To check for this, the examiner first looks for motor neglect by observing the patient’s awareness and spontaneous movement of the affected side. A simple check is to ask the patient to touch their nose with both hands simultaneously.
A more specific test for neglect is sensory extinction, where the examiner simultaneously touches the patient on both the affected and unaffected sides (e.g., both hands or both cheeks). If the patient reports feeling only one touch when both sides are stimulated simultaneously, this is a positive finding. Neglect is also indicated if the patient ignores one side of their body or the space around them.
A patient is considered “VAN Positive” if they exhibit the prerequisite arm weakness and have an abnormal finding in Vision, Aphasia, or Neglect. This combination of motor weakness and a cortical sign (V, A, or N) is highly predictive of an LVO stroke. A positive VAN screen mandates immediate activation of the LVO stroke pathway, typically involving direct transfer to a Comprehensive Stroke Center capable of performing endovascular thrombectomy. This rapid identification prevents delays in obtaining specialized imaging and mobilizing the neurointerventional team.