From a neuropsychological perspective, the most relevant model has been the clinical model of attention proposed by Sohlberg and Mateer,²a model based onthe observation of attention deficits in people who have suffered traumatic brain injuries. Through clinical observation, these authors consider attention as a multidimensional cognitive capacity divided hierarchically into five levels or types of attention: focused, sustained, selective, alternating, and divided. The following sections will deal in more detail with selective attention, its definition, the problems faced by people with impairments affecting their functioning, as well as the assessment and rehabilitation of attention.

What is selective attention?

Selective attention is the ability to maintain behavioral or cognitive set in the face of distracting or competing stimuli.

Based on Sohlberg and Mateer’s model,²and specifically on the hierarchical fashion in which the five levels of attention are organized, a minimal capacity to sustain attention is required before carrying out activities that involve selective attention. Let’s take a simple example: reading a newspaper in the subway. In this environment, there are multiple distracting stimuli, both visual and auditory, such as the sound of the subway, the voice calling the stops, people talking and moving, etc. For performing an activity such as reading the newspaper, which requires concentration and an understanding of what has been read, it is necessary to sustain attention on the task while inhibiting distractors. This is what we call selective attention, the ability to select relevant information we are focusing on for a period of time. For this reason, the correct functioning of sustained attention is a prerequisite for proper selective attention performance.

What happens when selective attention is impaired?

Impairments in selective attention involve greater distractibility to irrelevant stimuli, or at least, to stimuli that are unrelated to completing the task. Such distractors may be external (e. g., noise, movement) or internal (e. g., thoughts, pain).² Research in the normal functioning of attention in different conditions has shown that attention deficits are especially common in distinct clinical populations. For example, people with depression perform significantly poorer on tests of selective attention since ruminative thought, characteristic of these patients, is an internal distractor that leads to a loss of vigilance.³ People with schizophrenia also have extraordinary difficulties in selecting relevant stimuli while inhibiting irrelevant stimuli, and therefore, any unfamiliar stimuli are likely to catch their attention momentarily.^1,3 Individuals with Alzheimer’s disease and attention deficit hyperactivity disorder (ADHD) also exhibit a deficit in selective attention.^{3, 4}

Not only do these deficits prove to be a problem inthe performance of activities of daily living (e. g., inability to hold a conversation without getting distracted) but they are a constraint on rehabilitation itself, especially when it is carried out in stimulating environments (e. g., going to the supermarket as part of occupational therapy).²

Assessment of selective attention

Neuropsychological assessment of attention is fundamental; therefore, several tools have been developed for this purpose. The d2 Test, the Test of Everyday Attention, and the Stroop Color-Word Test are the most commonly used tests for assessing selective attention.

Broadly speaking, the d2Test⁵ is a cancellation task that asks participants to cross out alltarget stimuli (any letter “d” with 2 marks) that are presented in combination with other distracting stimuli (letters “d” and “p” with 1,3 or 4 marks). The Test of Everyday Attention(TEA)⁶ and the Test of Everyday Attention for Children (TEA-Ch)⁷ include ecological activities to assess sustained attention, divided attention, attentional control/switching, and selective attention. The following is an example of a measure of selective attention for adults: an elevator emits a sound each time it goes upone floor (low tone) and then emits a different sound when it goes down (high tone). The subject’s task is to count the number of times the elevator goes up one floor while ignoring distracting sounds.⁸ Lastly, the Stroop Color-WordTest⁹is a very popular task used to measure cognitive inhibition, selective attention, and processing speed. This test consists of three pages:

1) On the first page, the words of three colors (blue, green, and red) are printed in black ink and participants are asked to read the words as quickly as possible (Stroop Word).

2) On the second page, there are “Xs” printed in colored ink. Participants must call out the ink colors (Stroop Color).

3) On the third page, participants must name the color ink in which the words of the colors are printed, while ignoring the actual words themselves (Stroop Color-Word).

It is important to highlight the need for a comprehensive assessment of attention, not just of each individual type. Besides, in addition to psychometric assessment, it is ideal to obtain qualitative data on the functioning of attention in non-hospital settings. To this end, interviews can be conducted with both patients and family members to determinein which aspects or situations the attention deficit leads to more deficits. This information will be very useful when designing the intervention.

Rehabilitation of selective attention

As with other cognitive functions such as memory, general and specific objectives must be established when carrying out rehabilitation of selective attention depending on the individual characteristics of each patient. Therefore, intervention should be individualized and designed to restore, maintain or improve cognitive function through guided practice organized by increasing levels of difficulty. Once again, the functioning of other types of attention should be taken into account when assessing the extent to which they should be included in the rehabilitation program. For example, enhancing sustained attention can facilitate selective attention restoration. In addition, since the ultimate goal is to reduce the impact of impaired attention on an individual’s life, the effectiveness of rehabilitation should be assessed according to the improvements observed in their daily functioning, and not only through neuropsychological test results.

Another key aspect to consider in rehabilitation is the selection of tools. Different tools can be used depending on the patient’s individual needs (e. g., taking patient’s mobility into consideration), from traditional paper and pencil tasks (e.g., word searches) to virtual reality. What is incontestable, however, is that the use of instruments based on activities of daily living is becoming more and more common, as they increase ecological validity.

Accordingly, the NeuronUP platform is developing a series of activities, including tasks based on everyday situations requiring selective attention. Since we are constantly exposed to anenormous number of stimuli in our daily lives, it is possible to reflect a variety of everyday situations in games as part of therapeutic treatment.

However, to carry out this whole process, it is first necessary to consider a variety of mitigating factors: the applicability of the task, the target population, the stimulus modality (auditory, visual or both) and their design (color, size, movement, etc.), the scoring (correct answers, types of errors, time, etc.) and the parameters to be controlled so that the activity is as structured as possible. It is also necessary to have as reference a theoretical model that justifies the approach of the rehabilitation program.

In short, there is no doubt that clinical neuropsychology has grown significantly in a short time and continues to develop more and more thanks to initiatives such as these, which represent a considerable improvement in such an essential aspect as neuropsychological rehabilitation.

References

• Rebollo, M. A., & Montiel, S. Atención y funciones ejecutivas. Revista de neurología. 2006;42(2):S3-S7.
• Sohlberg MM, Mateer CA. Improving Attention and Managing Attentional Problems. Annals of the New York Academy of Sciences. 2006;931(1):359–75.
• Egeland, J., Rund, B. R., Sundet, K., Landrø, N. I., Asbjørnsen, A., Lund, A., … & Hugdahl, K. Attention profile in schizophrenia compared with depression: differential effects of processing speed, selective attention and vigilance. Acta Psychiatrica Scandinavica. 2003;108(4):276-284.
• dos Santos Assef, E. C., Capovilla, A. G. S., & Capovilla, F. C. Computerized Stroop test to assess selective attention in children with attention deficit hyperactivity disorder. The Spanish journal of psychology. 2007;10(1):33-40.
• Brickenkamp, R. (1962). Aufmerksamkeits-Belastungs-Test Handanweisung d-2.
• Robertson, I. H., Ward, T., Ridgeway, V., &Nimmo-Smith, I. (1994). The test of everyday attention (TEA). San Antonio, TX: Psychological Corporation.
• Manly, T., Anderson, V., Nimmo-Smith, I., Turner, A., Watson, P., &Robertson, I. H. The differential assessment of children’s attention: The Test of Everyday Attention for Children (TEA-Ch), normative sample and ADHD performance. Journal of Child Psychology and Psychiatry. 2001;42(08):1065-1081.
• Chan, R. C., Lai, M. K., & Robertson, I. H. Latent structure of the Test of Everyday Attention in a non-clinical Chinese sample. Archives of clinical neuropsychology. 2006;21(5):477-485.
• Golden, C. J. (1994). STROOP: Test de colores y palabras: Manual. TEA ediciones S.A.