How robust is performance on the National Adult Reading Test following traumatic brain injury?

Abstract

An NART given within 12 months of a severe TBI runs the risk of significantly underestimating pre-morbid IQ. If applied in this context, it is recommended that the NART score is used in conjunction with other methods of estimation, such as those based on demographic data.

Group Intervention Studies in the Cognitive Rehabilitation of Individuals with Traumatic Brain Injury: Challenges Faced by Researchers

“…With the advent of alternative forms of education, such as home-schooling or passing a GED exam in lieu of graduating from high school, and increasing numbers of adults returning to high school or college later in life, the years of formal education may no longer be the best indicator of educational experience. Rather, estimates such as the verbal intelligence quotient from the National Adult Reading Test (Nelson & Willison, 1991) for individuals at least one year after injury (Riley & Simmonds, 2003) might be more useful for equating groups than the years of formal education.…”

Impaired National Adult Reading Test (NART) performance in traumatic brain injury

“…Evidence of impaired NART performance, or under-estimation of premorbid IQ, in patients with dementia has been provided by several researchers (e.g., Cockburn, Keene, Hope, & Smith, 2000;Paolo, Troster, Ryan, & Koller, 1997;Taylor et al, 1996). Although there has been limited research, some findings suggest the NART may be impaired in TBI (Freeman & Godfrey, 2000;Freeman, Godfrey, Harris, & Partridge, 2001;Riley & Simmonds, 2003;Skilbeck, Allen, & Brechin, 2005). Riley and Simmonds (2003) conducted a longitudinal study, using the NART, to assess 26 patients with severe TBI within 12 months of injury, and then again 12 months later.…”

“…Although there has been limited research, some findings suggest the NART may be impaired in TBI (Freeman & Godfrey, 2000;Freeman, Godfrey, Harris, & Partridge, 2001;Riley & Simmonds, 2003;Skilbeck, Allen, & Brechin, 2005). Riley and Simmonds (2003) conducted a longitudinal study, using the NART, to assess 26 patients with severe TBI within 12 months of injury, and then again 12 months later. They noted significantly more NART errors on the first administration (M ¼ 26.3, estimated VIQ ¼ 97.4) compared with the second (M ¼ 21.8, estimated VIQ ¼ 102.5).…”

“…Nelson and Willison (1991) found only 5% of healthy adults had an estimated-minus-actual verbal IQ discrepancy of 12+ points, and suggested that this be the cut-off for diagnosing intellectual impairment. Using this cut-off, in the Riley and Simmonds (2003) study three participants would be diagnosed as intellectually impaired based on their first NART score, compared with seven using their second NART score. This suggests their first NART underestimated IQ and, consequently, underestimated intellectual impairment.…”

“…Although the longitudinal design of Riley and Simmonds (2003) is preferable to the commonly-used cross-sectional approach, and their inclusion criterion was strict for severe TBI (Glasgow Coma Scale , 9, or posttraumatic amnesia . 24 hours), their analysis included only 26 participants and was under-powered to adequately detect effects.…”