Subtests

Alertness refers to the condition of general wakefulness that enables a person to respond quickly and appropriately to any given demand. It is the pre-requisite for effective behaviour, and is in this respect the basis of every attention performance.

In this test, reaction time is examined under two conditions. The first condition concerns simple reaction time measurements, in which a cross appears on the monitor at randomly varying intervals and to which the subject should respond as quickly as possible by pressing a key. Intrinsic alertness is measured in this condition. In a second condition, reaction time is measured in response to a critical stimulus preceded by a cue stimulus presented as warning tone ("phasic arousal", or temporal orientation of attentional focus).

Sustained attention is not an ability that can be captured by a single type of task. On the contrary, continued maintenance of attention is required in tasks with very different cognitive demands, ranging from simple stimulus detection tasks to tasks with a high cognitive load.

Concentrating on a task is a typical requirement in working life. This involves focusing attention on a mentally demanding activity for a sustained period of time.

In this test, a sequence of stimuli is presented on the monitor. The stimuli vary in a range of feature dimensions: colour, shape, size and filling. A target stimulus occurs whenever it corresponds in one or the other of two predetermined stimulus dimensions with the preceding stimulus (e.g. the same shape but with different colour, size and filling). In order to adapt the difficulty of the task to the performance level of a subject, different levels of difficulty, that is, reactions to "shape" only or to "colour or shape", may be selected.

The measurement of vigilance is based on an investigative approach which concerns the detection of rare critical events that are difficult to discriminate and presented under extremely monotonous stimulus conditions.

Vigilance is a form of sustained attention in which the attentional focus is maintained by exerting mental effort over a longer period of time. The effect of monotony is however an essential aspect for the level of performance under vigilance conditions. This effect serves to clearly differentiate the vigilance paradigm from other tasks with higher cognitive demands.

There are three test conditions available for the vigilance examination, one auditory and two visual.

Covert shift of attention refers to the ability to focus visual attention to part of the surrounding space without changing the direction of gaze. This shift of attentional focus may be elicited exogenously by stimuli that catch the eye, or endogenously by voluntary orientation of attention to an expected or given event at a point in space.

In the present task, a central cue (an arrow directed to the left or right) indicates the expected side of the target stimulus. This allows the examination of endogenous control of attention of focus. The cue is correct (valid) in 80 per cent of the trials and incorrect (invalid) in 20 per cent. Following an invalid cue, attentional focus is initially shifted to the cued side (orienting), after which there is a new shift of focus to the actual occurrence of the target stimulus (reorienting).

In everyday life, the capacity to pay attention to several things at once is of great importance. This requires the ability for divided attention to simultaneously ongoing processes.

Deficits of divided attention are frequently diagnosed in neuropsychological practice. The affected patients complain, for example, of difficulties experienced at work when several demands are placed on them simultaneously. The situation is made more difficult for many patients in that activities they previously executed on a largely automatic basis now need to be consciously controlled following the damage.

In this test, a visual and an auditory task must be processed in parallel.

Two forms of this test may be administered.

One of the most efficient forms of focusing is to look at something, that is, to change the direction of gaze and fixating on relevant information in the environment. This is a central function, on the basis of which we explore our surroundings and are able to orient ourselves in a given situation. Impaired eye movement can represent a major handicap in road traffic and may result in impaired reading ability, especially when there is a right-sided manifestation. In rehabilitation a deficit in saccadic eye movements can render compensation training of a visual field defect considerably more difficult.

In this task, the latency of saccadic eye movement to the left or to the right is assessed in a reaction task. Either a critical or a neutral stimulus is presented to the left or right of a fixation stimulus (an "S" lying on its side) in pseudorandom sequence. A critical stimulus appears centrally at irregular intervals. The subject should respond as quickly as possible by pressing the key as soon as this critical stimulus appears.

The task is administered under two conditions: a "gap" and an "overlap" condition.

The exploration of the visual environment is one of the most basic abilities subserving the safe movement in space, the search for an object, when regarding an object or picture, or in monitoring and controlling a traffic situation. It is a complex process for which the intention and prior knowledge of the individual, the ability to plan ahead, an unrestricted visual field, the ability to shift visual attentional focus, and unimpaired eye movements are important. Equally diverse are the causes of a deficit in exploring the environment after brain damage, which in many cases presents an obvious handicap in daily life.

In this task, a matrix-like arrangement of 5 x 5 stimuli is used, the aim being to detect whether this arrangement includes a critical stimulus or not. One reaction key is used for the answer ""present"" and another for the answer ""not present"".

The requirement to explore the matrix on a row-by-row or column-by-column basis permits testing of the ability to shift the required search strategy, which can be impaired, for example, in the case of frontal brain damage.

Visual field defects represent a serious handicap for the affected patients. Pronounced visual field defects render the exploration of the environment difficult , with corresponding consequences for daily work procedures. Furthermore, reading ability may be considerably limited by a hemianopsia or a larger defect of the horizontal visual field, especially to the right side.

Information about visual field deficits is also important for the feasibility of administrating different tests of this battery, for the planning of rehabilitative measures, and especially for compensation training of the visual field defect.

To record vision in circumscribed areas of the visual field, a flicker stimulus is presented at different points of the screen and at varying intervals. A simultaneous central task should hereby insure that the subject fixates on the middle of the screen throughout the entire test run. Whenever the peripheral stimulus appears the patient should press the reaction key as quickly as possible.

Two variants of the test, referred to as the Visual Field test and the Neglect test are available. When administering the Visual Field test, a peripheral flicker stimulus appears on an otherwise empty background. In the condition Neglect test, the screen is filled with a mask of numbers in order to provoke extinction.

In everyday life, we recognise a person by their voice or their gait, and an object by its characteristic sounds, smell or tactile features. In short, we have a multimodal impression of persons and objects that enables us to identify them and to localize them rapidly in space.

In this task, the critical combination of a preceding tone (high or low) and a subsequent visual stimulus (an arrow pointing up or down) should be detected. A target stimulus occurs when the pitch of the tone and the direction of the arrow are in agreement (high pitch and an arrow pointing up or a low tone and an arrow pointing down).

Paying attention to specific aspects in our surrounding world is not a static process. On the contrary, it is essentially an active process by which we turn our attention away from objects in order to effectively deal with other objects. In daily life and in the execution of work, it is necessary to gear our attention again and again to newly relevant aspects of a situation.

This procedure is a "set shifting" task. Either a letter and a number (condition "verbal") or angular and round figures (condition "non-verbal") are simultaneously presented to the right and left of the centre of the monitor. For both conditions, there is the possibility to choose between a simple test mode with a fixed target stimulus (e.g. requiring a reaction only to letters or only to the angular shapes) or a complex mode, with alternating types of target stimuli (i.e. requiring a reaction to the complementary target stimulus on an alternate basis from trial to trial, for example, the sequence under the condition "verbal": letter - number - letter - number ...). The subject has the possibility to press a left or a right key. The subject's task is to press the left or right key according to whether the target stimulus (e.g. letter or number) appears to the left or the right of the centre of the monitor.

An important aspect of behavioural control is the ability to perform an appropriate reaction under time pressure and to simultaneously inhibit an inappropriate behavioural response. The Go/Nogo paradigm was developed to test this form of behavioural control, in which it is important to suppress a reaction triggered by an external stimulus to the benefit of an internally controlled behavioural response. In this paradigm, the focus of attention is directed to predictably occurring stimuli that require a selective reaction, that is, to react or not to react.

A deficit in this form of behavioural control is particularly seen in patients with a frontal symptomatic. These patients frequently show above-average reaction speeds in simple reaction tasks, where as in a Go/Nogo task they show either a much higher number of incorrect reactions, or much higher reactions times compared with the simple reaction task. The latter deficit is indicative of difficulties in decision processing in the control of behaviour. Investigations with imaging techniques have provided evidence for the role played by frontal structures in executing a Go/Nogo task.

Two administrative forms of this test may be administered.
Test Form "1 of 2" (1 of the 2 stimuli is critical): an up-right ("+") and a diagonal ("×") cross are presented in an alternating sequence on the screen.
Test Form "2 of 5" (2 critical stimuli among 5 stimuli): A sequence of five squares with different patterns appears on the screen. Two of these squares are defined as target stimuli.

Incompatibility occurs in a conflict situation in which divergent stimulus information has to be processed in parallel, thus triggering different reaction tendencies. The Simon and the Stroop effects (in the Colour-Word Interference Test) are classic examples of this effect.

The present procedure tests the interference tendency in terms of stimulus-reaction incompatibility (Simon effect) . For this test, arrows that are directed to the left or the right are presented on the left or the right of a fixation point. Depending on the direction of the arrow, the test person should respond with the right or left hand irrespective of the side on which the arrow is presented.

Working memory may be understood as a system that maintains the information necessary for solving complex problems and processing multi-level tasks or aspects of a situation in order to generate an overall picture. An essential aspect of this is that, depending on the task and the goals of the individual, the content of working memory must be updated continually. Deficits in working memory can therefore lead to considerable difficulties in solving problems, structuring complex work processes or adapting to a given situation, independent of problems in memory in the form of impaired encoding, consolidation, and retrieval.

This task examines the control of information flow and the updating of information in working memory. A sequence of numbers is presented to the subject on the monitor. The subject is required to determine whether each number - depending on the condition - corresponds with the previous number or the one before that. Three conditions with different levels of difficulty can be selected.

The test is not suitable for patients with language disorders because of its verbal material.