COGNITO - Inserm · PDF file2. Introduction . COGNITO is a computerized neuropsychometric...
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Introduction Construction of the
battery Getting started
Administration How to administer the tests and record
Results How performance is
recorded in the Results file
Introduction COGNITO is a computerized neuropsychometric examination based on well-known cognitive tests designed for both cognition research and clinical assessment. It was originally developed with MacIntosh Hypercard software (version ECO) for use in both population and clinical studies of brain ageing and has now been up-dated into Flash, thus extending its hardware possibilities. The original version was used in a prospective population study from general practice from which normative data was derived, and the ability of the battery to detect difficulties in information processing two years prior to the diagnosis of dementia was also established. The battery has been subsequently used to track cognitive changes due to depression, following anesthesia, as a consequence of anticholinergic drug use, and in the development of diagnostic criteria for mild cognitive impairment (MCI). More recently COGNITO has been used to monitor cognitive changes during treatment in schizophrenia. COGNITO assesses reaction time, primary and working memory (an articulation sub-test further permitting identification of problems related to the articulatory loop) visuospatial and verbal secondary memory (with free, cued and multiple choice paradigms) , implicit learning (priming), language skills (word and syntax comprehension, naming, verbal fluency), functional and semantic categorization of visual data (visual reasoning and form perception), focused and divided attention (visual and auditory modalities) and crystallized intelligence (vocabulary).
Responses are made via a tactile screen which permits the recording of response latency (deducting reaction time provides an estimation of information processing time). The examination may be carried out by trained lay interviewers with the possibility of the interviewers voice being replaced by pre-recorded instructions. The interpretation of the results can only, however, be made by a clinician competent in neuropsychology. Qualitative aspects of performance (perseveration, intrusions, visual field neglect) are also recorded. The test is suitable for children over 12 and adults of any age provided they are able to read, hear instructions and see the words and images. Practice trials are given which may be repeated until the subject has understood what is required. In order to be able to test highly performing persons some of the tasks become very challenging, so some tests stop automatically after repeated failures to avoid discouragement. The examination takes 45 minutes to an hour to complete depending on the ability of the subject. While it is possible to select and administer specific tests, it is suggested that the whole battery be given where possible in order to standardize fatigue effects and the time delay between the presentation of memory stimuli and the recall trials.
GETTING STARTED Home page
Identification page Subject details and test selection
1. HOME PAGE
On this page select either the French or the English version of COGNITO. From this page you may start a new testing session, complete an examination which has already been started or exit from the battery. You must select one of these options by the mouse or touching the screen in order to proceed with the examination or end the session.
2. IDENTIFICATION In order to begin testing a file name must be entered. This will be the name given to the Results file which will appear automatically on the Desktop upon completion of the examination. You may then either cancel the session (in which case no file will be created) or touch Enter in order to continue.
3. SUBJECT DETAILS The date and time of the examination will be entered automatically but may be modified. Age, sex and a subject identifier must be given. The interviewer may add remarks here relating to test conditions. The Summary button will show the list of tests and those which have already been administered (in the case of redoing the battery). A filled in white dot next to the test name indicates a completed test, a half-filled dot an uncompleted test. See page 5 for further functions on this menu.The Start button commences testing.
1. REACTION TIME
The test measures simple reaction time using the dominant hand. When a stimulus (a clown) appears on the screen, the subject must press the space bar. The time recorded appears on the screen.
Trials are given with random inter-trial intervals.
The reaction time is recorded to one hundredth of a second. A correct response will be between 100 and 500 milliseconds.
If the subject responds before 100 milliseconds it is counted as an Anticipation error. If the subject responds between 500 and 2000 milliseconds it is considered a time Lapse problem (an very slow response - subject has probably been distracted from a correct response leading to a possible outlier score). If the subject does not respond at all after 2 seconds it is considered a failure (Over Time error).
The test is terminated when the subject has recorded 12 valid responses. A maximum of 36 trials may be given.
In the Results file the following are recorded:
- Validity of response for each trial - The mean of the 12 valid responses - Total number of trials by the subject - The number of Anticipation errors - The number of time Lapses - The number of Over Time errors
After reading the instructions to the subject press the Start button to begin the 5 Practice trials.
The subject should have his finger just above the space bar in preparation for each stimulus. The practice trial may be repeated as often as necessary if the subject has difficulty in understanding the instructions or begins to touch the bar before the stimulus has appeared.
The interviewer should only start the real test when the instructions are understood
2. FAMILIARISATION TASK USE OF THE TESTING MENU
This task is designed to familiarize the subject with the tactile screen. It is not scored or recorded in the results. The subject is asked to touch the stimulus (the clown from the reaction time test) and differentiate two stimuli (name of the clown). The subject then touches the clown at 3 different places on the screen.
The testing menu
Taking the cursor or touching the upper part of the screen will make a menu bar appear in green. From this menu the interviewer may activate/disactivate a voice which reads the instructions for each test, see the list of tests which have been started and completed, go to the next test or back to the last test, return to the COGNITO home page or exit from the battery. This menu accompanies every test in the battery.
3. READING AND SYNTAX COMPREHENSION
The test is in two parts. The first a simple reading task and the second a comprehension task in which the subject carries out instructions of increasing syntactical complexity.
The subject is given one practice trial. If the subject is unable to read and understand the sentences then it is unlikely that the results for subsequent tests will be valid. Press the Start button to commence the test.
The subject is required to read the sentence. This is scored by the interviewer as C=Correct or I=Incorrect. The scoring options are activated by passing the mouse or touching the upper right hand part of the screen. This must be done in order to move on to the next part of the test. If the subject does not respond within 10 seconds the next trial is given and a Time error noted.
The subject must now carry out the instruction given in the sentence. This will be scored as Correct or Incorrect in the Results file along with the response latency (time taken to reply). The subject is given 5 trials.
The following appears in the Results file:
- Number of sentences read
- Number incorrectly read
- Number correctly understood
- Incorrect response corrected
- Number of Time errors
4. AUDITORY ATTENTION
The subject is asked to discriminate between long and short sounds presented at variable intervals and to count only long sounds. The interviewer should use the practice trial to determine whether the subject has hearing difficulties which may hinder the completion of the task. Press the Start button to begin.The screen is blank and the subject should look at the screen while counting in order to standardize competing environmental stimuli.
10 trials are given. After each trial a counter appears on which the interviewer should note the reply given by the subject, then press OK to start the next trial.
The following will appear in the Results file:
- The number of correct responses
- The total number of errors
- The number of overestimations
- The number of underestimations
5. VISUAL ATTENTION
The subject is shown a shape for 2 seconds then a screen with variations on this shape of which two are the same. The subject must visually locate and touch the two similar shapes. When the subject touches the correct shape it changes from red to blue. If a change of colour does not occur the subject should be asked to touch with a larger surface of the fingertip. Two practice trials are given.
10 trials are given. If the subject does not respond within 30 seconds then this is scored a Time error and the next trial is given. If the subject touches the wrong shape then