EXAT is a diagnostic tool to be used via Epsilon computer platform. It is designed to diagnose ADHD in children and adolescents aged 7–19.

DEVELOPMENT AND THEORETICAL FOUNDATION

Development of the EXAT test started with a thorough review of research concerning cognitive deficits observed in ADHD. One of the purposes of the publications review was to find examination procedures which best differentiate persons diagnosed with ADHD from those in general population and those with other disorders. Reviewing hundreds of studies we identified cognitive functions which are most often disordered in ADHD and types of tasks most useful to detect and recognize these deficits. The tasks included in the final version of the test originate in the research of experimental cognitive psychology. They were, however, modified for the purposes of psychiatric and psychological diagnosis of children and adolescents.

The EXAT theoretical foundations refer to contemporary neuro-cognitive conceptions of ADHD, in the first place to the hypothesis of “default-mode networks” (Castellanos, 2012), the hypothesis of “hot processes – excitement regulation” and “cool processes – cognitive functions” (Rubia, 2011) as well as to the model of self-control and self-regulation disorder in children and adolescents (Diamond, 2011).

These conceptions consider cognitive control disorders to be the main cognitive function deficit in the ADHD. Due to the control deficit information processing in short-term memory as well as cognitive and behavioural inhibitions are impaired. There is a mutual two-ways causal dependence between the efficiency of short-term memory and inhibition. Memory deficit causes difficulties in maintaining the purpose and this in turn disorganizes purposeful action and inhibition of inadequate reactions, whereas inhibition deficit hampers the process of ignoring distractions and this in turn leads to memory overload. The EXAT test tasks were designed to measure efficiencies of the aforementioned cognitive functions. Theoretical models of the ADHD referred to above take into account the deficits of both emotional-motivational control and arousal control. It is assumed that these deficits are responsible for the elevated level of activity, impulsiveness and motivational problems observed in the ADHD. We expect that some of the EXAT indices will be sufficiently sensitive to these difficulties experienced by persons with ADHD. Failures in the aforementioned mental processes lead to axial symptoms of the ADHD such as hyperactivity, impulsiveness and attention deficit. They are also related to other problems experienced by persons with ADHD including executive deficit (associated with procrastination) or difficulties in cognitive tasks (associated with phonological awareness).

STRUCTURE OF THE TEST

The EXAT test is composed of three different tasks. Although each task requires cognitive control and attention to be engaged they provide knowledge about the efficiencies of various cognitive functions.

The task no. 1 measures the following deficits associated with cognitive control and memory:

• simultaneous retention and processing of information in working memory,
• maintaining the goal and phonological awareness,
• long-time attention focus on the performed action,
• control over one’s own mental processes,
• coping with demanding and difficult tasks.

The tasks no. 2 and 3 measure the following deficits associated with cognitive control and memory:

• long-time attention focus on the task,
• vigilance,
• shifting of attention,
• selective attention,
• ignoring distraction stimuli,
• response inhibition and impulse control.

EXAT SCORES

The EXAT tasks enable to register a large number of indices based on the number and type of errors and on response times. To develop indices referring to the ADHD symptoms and cognitive deficits each of the several indices will be used as item and assigned to one of the measured dimensions. As a result test scores will have a form of compound indices which refer to the axial ADHD symptoms as included in diagnostic criteria as well as indices which measure cognitive functions the efficacy of which is lowered due to the disorder. In order for the indices to reflect the intensities of measured dimensions in a best possible way the scores will be calculated by means of a psychometric model related to the Item Response Theory and adapted to the specificity of the EXAT test.

Materials*:

• Test manual
• e-EXAT test unit

* TheEXAT test can only be administered via the Epsilon computer-based testing platform.

REFERENCES

Castellanos, F.X. i Prola, E.(2012). Large-Scale Brain Systems in ADHD: Beyond the Prefrontal-Striatal Model. Trends in Cognitive Sciences 16(1)
Diamond, A. (2011). Insights from neuroscience and developmental science on ways to improve cognitive control and self-regulation in young children and why that’s important. Minneapolis: MNRubia, K. (2011). "Cool" inferior frontostriatal dysfunction in attention-deficit/hyperactivity disorder versus "hot" ventromedial orbitofrontal-limbic dysfunction in conduct disorder: a review. Biological Psychiatry. 69(12)