The Wechsler Test of Adult Reading (WTAR) is a neuropsychological assessment tool used to provide a measure of premorbid intelligence, the degree of Intellectual function prior to the onset of illness or disease.
[2] Using vocabulary level as a correlate to IQ, the test relies on reading recognition’s resistance to the cognitive impacts of brain damage to estimate premorbid function.
Since the patient cannot apply standard pronunciation rules to complete the task, the examiner can assess their vocabulary by their ability to pronounce the irregularly spelled words, and by extension, estimate their premorbid IQ.
[2] Patients recovering from traumatic brain injury (on average measuring in severely impaired ranged on the Glasgow Coma Scale) showed high stability in WTAR scores during their recovery period while performing highly similar to demographic estimates, suggesting the test is a reliable estimate of premorbid intelligence in individuals with TBI.
[6] In patients with Alzheimer's disease, WTAR scores declined as the degree of cognitive impairment increased in more affected individuals.