Testing the Effect of Environmental Distraction: An Innovative Procedure for Improving Differential Diagnosis and Ecological Validity of the Neuropsychological Assessment

Traditional neuropsychological assessments are conducted exclusively in a quiet, distraction???free environment; clients??? abilities to operate under busy and distracting conditions remain untested. Environmental distractions, however, are typical for a multitude of real???life situations and present a challenge to clients with frontal???temporal brain injury. In an effort to improve ecological validity, an extension of the traditional neuropsychological assessment was developed, comprising a standardised distraction???condition. This allowed cognitive functions to be tested both in the traditional setting and with exposure to a specified audio???visual distraction. The problem of practiceeffects arising from re???testing clients in two conditions was resolved by developing a set of alternative test stimuli that which can be used interchangeably with the standard stimuli. A first study (n=240), comprising clients with mild Traumatic Brain Injury (mTBI) (n=80), clients with Major Depression (MDE) (n=80), and a healthy control sample (n=80), was undertaken to validate the equivalence of the alternative stimuli. The second study (n=240) investigated how clients with mTBI (n=80), clients with MDE (n=80), and a healthy control sample (n=80) performed on sub???tests of the Wechsler Adult Intelligence Scale???IV and the Wechsler Memory Scale???IV both in the standard and the distraction conditions. Significant deterioration of performance in the distraction setting was observed among clients with mTBI. In contrast, the performance of a healthy control sample remained unchanged. Significant improvement of performance in the distraction setting was documented for clients with MDE. Contrary to their improved performance, depressed clients experienced the distraction setting as more distressing than the control group and the mTBI group. Keywords: Environmental Distraction, Neuropsychological Assessment, Ecological Validity, Environmental Distraction, Traumatic Brain Injury, Major Depressive Episode, Practice Effect