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Bawl battery presentation

 

Bawl

Cliquez ici pour la version en français

 

The BAWL battery (Batterie Attention William Lennox) is a computerized tool for assessing different attentional components. It has been constructed in a neuropsychological aim. However it can be useful in other domains: psychiatry, cognitive psychology, gerontology, as additional informations after physical examination, etc. With its structure, it targets more specifically the assessment of adult subjects (there are no norms for children populations).

 

The different tests of the battery have in common the use of simple tasks, solliciting a minimal level of cognitive processing. The majority of the tasks has been constructed from a common structure (type of items, interstimuli intervals and presentation modalities) in order to favour the reliability for comparisons between tasks. The low level of cognitive processing  linked to the simplicity of the tasks and the common structure of most of the proposed tasks improve the control of the implicated variables when analyzing a subject's performances.

 

Material needed : a PC with a Pentium 200 processor, or all more recent material. The software has been tested  and works without any difficulty until and including Windows 8. The capacity of the random access memory has to be at least of 32 Mo for Windows 95 and 1Gb for Vista. The computer must be connected to a mouse which will serve as response button.

 

 

The battery includes a total of ten reaction time (RT) tasks. Most of these tasks exist in different versions differentiating mostly by the number of items which compose them. The tasks imply one or two sensorial modalities: visual and/or auditory. The RT are recorded in milliseconds.

The entire pool of tasks can be subdivided into four categories : (a) a set of tasks of simple  RTs (b) a subgroup of tasks for the assessment of selectivity and (c) some more specific tasks targeting the assessment of the hemineglect. Some of the battery tasks can also be used simultaneously with others in order to assess (d) divided attention.

Short description of the tasks included in the battery


* Simple reaction time tasks
* Selectivity
* Hemineglect
* Divided attention


A. Simple reaction time tasks:

This set of tasks only requires from the subject that he/she detects elementary perceptive signals to which he/she will have to react as quickly as possible by depressing the response button (mouse). A reaction is expected for each presented signal: there are no distractors.


Visual centred RT: subject has to react as quickly as possible when a black square appears systematically in the centre of the screen. There are three versions of this task according to the number of items : 16, 32 or 64.


Auditory RT: subject has to react as quickly as possible when the computer emits a continuous low sound. There are also three versions of this task: 16, 32 or 64 items .


Mixed RT: task using two sensorial modalities: visual and auditory. Subject has to react as quickly as possible when a black square appears systematically in the centre of the screen but also when the computer emits a continuous low sound. The items of the two modalities are presented in a pseudorandom order, chronology which doesn't allow the subject to anticipate the modality of the stimulus to which he will have to react. This task includes 65 items.


The tasks of lateralized RT (with or without fixation point) described below in the section " Hemineglect " are also tasks of simple detection.

 

B. Selectivity:

This set of tasks is based on a Go/Nogo paradigm where the subject response depends on some specific conditions. Multiple choice RT tasks are to be prefered for selective attention assessment and analysis.

 

In the Simple Binary RT, two types of visual signals (a cross and a circle), appear on the screen. Subject is instructed to react only when one (the cross) of the two is presented, inhibiting any response to the presentation of the other (the circle). This task exists in two versions : 32 (20 targets + 12 distractors) or 64 items (40 targets + 24 distractors).

 

The Double Binary RT includes four signals differentiating by one or two specific features, i.e. color and/or form: a red or blue cross and a circle, also red or blue. Subject has to depress the response key only when two of these signals (red cross and blue circle) appear, inhibiting any reaction to the presentation of the two distractors (blue cross and red circle). This task also exists in two versions: 32 or 64 items.

 

The task of Sustained Attention combines selectivity and sustained attention. Its aim is to study the subject’s capacity to inhibit selectively a response (depressing response key) frequently emitted (automatization). Indeed, subject has to react systematically to the frequent presentation of letters in variable sizes (capital or small letters), inhibiting any reaction to the much more rare presentation of the digit 3. This task exists in three versions which are different according to the duration of the stimuli  presentation on the screen: 750, 1000 or 1250 milliseconds.

 

The task of Mixed RT decribed above can also be used as a selectivity  task; in this case, subject will be instructed that he/she has to react only to signals of a specific modality (for example, only to sound), inhibiting any reaction to the others (visual : square).

 

C. Hemineglect:

Set of tasks aiming the assessment of a deficit in information processing situated in a specific part of the subject’s own or external  space.

 

Lateralized RT: task of visual simple RT, “lateralized” meaning that the targets (a black square) are appearing in different locations on the screen ; with this presentation mode one can compute the RT according to their topography of presentation. There are two versions of this task: 36 or 64 items.

 

Lateralized RT with central fixation: this task is identical to the previous one but with the presence of a small window situated in the centre of the screen where from time to time appears a group of 9 points of which subject has to indicate the presence. The monitoring of this window aims to limit the subject’s visual scanning by forcing him/her to maintain continuously his/her gaze fixed on the centre of the screen. As for the lateralized RT there are two versions of this task (36 or 64 items).

 

Flea square: this task aims to assess the presence of possible hypomotricity in the subject’s neglected hemifield. In practice, he/she has to click with the mouse in a small-sized square. When clicking the square is erased and  appears again immediately in another  location on the screen. These movements imitate the jumps of a small insect, hence the « flea ». Task includes 64 items.

 

Flea asterisk: task similar to the previous one but where subject has to click on a symbol in the form of a star (asterisk). This symbol is of small size and, comparatively to the previous task, requires better motor precision from the subject. As the previous, the task includes 64 items.

 

D. Divided attention:

Several tasks of the battery can be used jointly with other verbal and/or motor tasks in order to assess the subject's capacity to divide and/or allocate correctly his/her attention on different tasks he/she has to conduct simultaneously.


Table below recapitulates different particularities of the proposed tasks:

Tableau 1 en

In this table, the sign [+] means that these tasks can be administered with a non pre-fixed number of items, particularity which is among others useful in double tasks paradigms.

 

The manual which goes with the battery includes the normative data of the tasks collected with a population of nearly 300 subjects. The following table lists on the one hand, the actual distribution of control subjects by task and age and, on the other hand, the total number of passations performed.

Tableau 2 en

A complete demonstration version (in French) is available for downloading on this web page. You can also download the manual (without the normative data).

For all information: Jean-Pierre PETERS

e-mail: jpp.dtvision@gmail.com