Cognitive Function Scanner®
Functions and Parameterization


Copyright © 1982-2008 by Peter Laursen, DPsySc, DMedSc, PhD

The Cognitive Function Scanner® system was developed in 1982 with the purpose to establish a computer-aided, standardized, reliable and economical method for assessment of general cognitive status. During the following years the Cognitive Function Scanner system was further refined in close collaboration with its users. Today the Cognitive Function Scanner is a comprehensive state-of-the-art assessment tool including nine tests of learning and memory, psychomotor function, visuospatial function, attention, perception, and vigilance producing a total of 45 psychometric parameters all normed on the basis of large epidemiological studies of the general Danish population. In addition to the psychometric parameters the system includes a detailed time-linked recording of the response process in accordance with the recommendations of modern cognitive psychology, supplying essential information for interpretation of the test results. Like all scoring and time measurements the recording of the response process takes place "in the background", i.e. without any signs which could disturb the tested subject. With the Cognitive Function Scanner you can freely switch between 12 languages (Danish, English, Faroese, Finnish, French, German, Norwegian, Portuguese, Spanish, Swedish, Serbo-Croatian and Turkish).

The Cognitive Function Scanner system is briefly characterized as follows:

  • The level of difficulty of each psychological test is selected so that it allows not only to distinguish between clearly pathological and normal conditions but also to detect even mild degrees of cognitive dysfunction
  • A set of reference values based on a large sample of the general population (N=1,026) may be used as guidelines for the evaluation of a client's performance on a psychometric basis
  • A qualitative process-oriented approach may be used for the evaluation of a client's functioning on the basis of cognitive process theory
  • All time measurements are recorded automatically without intervention by the examiner, and they are accurate to the tenth of a second as a minimum (the Reaction Time Test to the tenth of a millisecond)
  • The tests are parameterized in a way that makes them suitable for subsequent statistical analyses
  • The tests are selected with the clear aim that they appear meaningful in relation to everyday tasks and thus stimulate the subject's motivation to work at his full capacity
  • The sensitivity of the tests to cultural differences is limited as much as possible in order to make them applicable for examination of different population groups
  • The duration of the Cognitive Function Scanner examination of central psychological functions is on the average shorter than the duration of traditional test methods. A well functioning subject will be able to complete the tests in approximately one hour.
  • Picture 1
    A view from the examination room
    Notice that examinee and psychologist sit side by side

    The purpose of the inclusion of detailed response process parameters in the Cognitive Function Scanner system is not to abandon the psychometric qualities of cognitive testing, but to supply helpful information for the interpretation of the psychometric outcomes in complex diagnostic cases. The recording of the response process is obtained by watching each step of the response flow linking response content with time latency measured in a continuous series and with an accuracy of a fraction of a second.

    Learning and Memory

    The Cognitive Function Scanner system comprises three tests for learning and memory: one predominantly for testing the right-hemisphere function of the brain and two predominantly for the left-hemisphere function. For the examination of the right-hemisphere function a face recognition test is used. For the examination of the left-hemisphere function a word recognition test and a two-digit numbers series test are used. The latter is administered according to Buschke and Fuld's word series test featuring a selective reminding procedure.

    The first test in the system is the Face Recognition Test. This test was chosen because it is easy and therefore offers a "soft" introduction to the test situation. It consists of three series of portraits presented on the computer screen (video-digitized black and white pictures of very high quality). The first series is composed of nine portraits, which the subject is asked to look at carefully so that he will be able to point them out when he sees them among 25 other portraits. Every stimulus picture is shown for five seconds. The second series consists of 34 portraits, among which are the nine stimulus portraits. This series is run immediately after the first series and the subject is asked to respond "yes" or "no" to every portrait presented. The subject gives his responses at his own pace via the examinee keyboard. Once a response has been given, correction is not possible. The test also includes a retention section approximately 1 hour later, after the other tests have been completed.

    Picture 2
    Responding to the Face Recognition Test

    The selection and arrangement of the stimulus pictures are made according to a random procedure each time the test is initialized in order to reduce the test re-test effect. The parameters of the test are:

    Short-term memory:

  • Number of unrecognized faces
  • Number of incorrectly recognized faces
  • Response latency for each item in seconds
  • Response latencies total in seconds
    Retention:
  • Number of unrecognized faces
  • Number of incorrectly recognized faces
  • Response latency for each item in seconds
  • Response latencies total in seconds.

    The second test in the system is the Word Recognition Test. It is designed exactly as the Face Recognition Test, thus allowing comparison between the functioning of the two brain hemispheres. The test consists of three series of adjectives presented on the computer screen. The first series is composed of nine words, which the subject is asked to look at carefully so that he will be able to point them out when he sees them among 25 other words. Every stimulus word is shown for five seconds. The second series consists of 34 words, among which are the nine stimulus words. This series is run immediately after the first series and the subject is asked to respond "yes" or "no" to every word presented via the examinee keyboard. Once a response has been given, correction is not possible. The test also includes a retention section approximately 1 hour later, after the other tests have been completed.

    As with the Face Recognition Test the sequence of the stimulus words is made according to a random procedure each time the test is initialized in order to reduce the test re-test effect. The parameters of the test are:

    Short-term memory:

  • Number of unrecognized words
  • Number of incorrectly recognized words
  • Response latency for each item in seconds
  • Response latencies total in seconds
    Retention:
  • Number of unrecognized words
  • Number of incorrectly recognized words
  • Response latency for each item in seconds
  • Response latencies total in seconds.

    In the third learning and memory test in the Cognitive Function Scanner system, the Number Learning Test, the subject is asked to remember eight two-digit numbers which are randomly generated by the computer in the interval 21-99. The numbers are shown on the computer screen at intervals of three seconds. When the numbers are presented, the subject is asked to read them aloud concurrently with their appearance on the screen. When all eight numbers have been shown, the subject is asked to respond. He may enter the numbers in any order he likes by means of the digit keys on the examinee keyboard. If some numbers are missing, only the missing numbers are shown to him again on the screen. After a few seconds, when the screen is cleared, the subject has to enter all eight numbers again. If some of the numbers are still missing, these are shown again. The test continues with this selective reminding until the subject has learned all eight numbers, or to the maximum of 10 trials.

    The number series is automatically changed each time the test is initialized.

    Like the two former tests the Number Learning Test includes a section of retention in which the subject is asked to enter the numbers he remembers. This entry is made approximately 1 hour after the learning process is completed. The parameters of the test are:

    Short-term memory:

  • Number of unrecalled numbers in the first trial
  • Number of "invented" numbers in the first trial
  • Number of perseverations in the first trial
  • Response latency for each response in seconds
    Learning:
  • Number of unrecalled numbers in each trial
  • Number of retrieval errors in each trial (i.e. numbers which have been entered at least once but for a period of time were unretrievable during the learning process)
  • Number of "invented" numbers in each trial
  • Number of perseverations in each trial
  • Response latency for each response in seconds
  • Total number of unrecalled numbers
  • Total number of retrieval errors
  • Total number of "invented" numbers
  • Total number of perseverations
  • Response latencies total in seconds
    Retention:
  • Number of unrecalled numbers
  • Number of "invented" numbers
  • Number of perseverations
  • Response latency for each response in seconds
  • Response latencies total in seconds.

    Psychomotor Function

    The Cognitive Function Scanner system comprises two tests of visuomotor function, the Figure Drawing Test for the continuous function and the Pen-to-Point Test for the discrete function. Both brain hemispheres are examined separately. In both tests the examination is started with the dominant hand.

    Picture 4Picture 5
    Responding to the Figure Drawing Test and the Pen-to-Point Test

    Both tests are made with the help of an electronic drawing pad (digitizer). In the Figure Drawing Test the subject is asked to trace a curved line with a ballpoint pen without ink. The Pen-to-Point Test is a kind of simulated pegboard test. It consists of a number of small crosses placed on a straight line. The subject is asked to point out the center of each cross with the tip of the ballpoint pen without ink.

    The parameters of the Figure Drawing Test are:

    Motor precision:

  • Dominant hand, deviation from the printed line in millimeters
  • Dominant hand, number of pen liftings
  • Non-dominant hand, deviation from the printed line in millimeters
  • Non-dominant hand, number of pen liftings
    Speed:
  • Dominant hand, time in seconds
  • Non-dominant hand, time in seconds
    Spatial orientation:
  • Dominant hand, drawing direction
  • Dominant hand, visual side-discrepancy
  • Non-dominant hand, drawing direction
  • Non-dominant hand, visual side-discrepancy

    The parameters of the Pen-to-Point test are:

    Motor precision:

  • Dominant hand, deviation from the cross center in millimeters
  • Non-dominant hand, deviation from the cross center in millimeters
    Speed:
  • Dominant hand, time in seconds
  • Non-dominant hand, time in seconds.

    Visuospatial Function

    The sixth test of the Cognitive Function Scanner system, the Parallelogram Test, aims at measuring visuospatial function. The test consists of 10 groups of 3 parallelograms each all printed on the drawing pad. For each group the subject is asked to determine orientation and congruity between the parallelogram to the left and the two other parallelograms. The ballpoint pen without ink is used as response (pointing) device.

    Picture 6
    Responding to the Parallelogram Test

    The parameters of the test are:

    Visuospatial function:

  • Response position for each group
  • Number of errors
    Speed:
  • Response latency for each group in seconds
  • Response latencies total in seconds.

    Concentration Function

    The concentration function is assessed by means of the Continuous Graphics Test. The test is composed of three simple periodically repeated graphic patterns. The subject has to copy these patterns on a row of squares on the drawing pad with the ballpoint pen without ink. Because of lack of visual feedback from the "invisible" drawing the subject has to remember the pattern and to be aware of how far he has reached in the pattern.

    Picture 7
    Responding to the Continuous Graphics Test

    The parameters of the test are:

    Concentration (evaluation by artificial neural network):

  • Pattern sequence in the first pattern
  • Number of errors in the first pattern
  • Pattern sequence in the second pattern
  • Number of errors in the second pattern
  • Pattern sequence in the third pattern
  • Number of errors in the third pattern
    Speed:
  • Response latency for each pattern element in the first pattern in seconds
  • Time in seconds in the first pattern
  • Response latency for each pattern element in the second pattern in seconds
  • Time in seconds in the second pattern
  • Response latency for each pattern element in the third pattern in seconds
  • Time in seconds in the third pattern.

    Attention, Perception, and Vigilance

    The Bourdon-Wiersma Test is a commonly used test of combined visual perception and vigilance. Also widely used as an attention and vigilance test is the reaction time test at different levels of complexity with visual or auditive stimuli.

    Picture 8
    Responding to the Bourdon-Wiersma Test

    The Bourdon-Wiersma Test in the Cognitive Function Scanner system is composed of 37 rows of 25 dot groups of either three, four, or five dots. The subject is asked to search the rows and mark all the four-dot groups. The test is done on the drawing pad with a ballpoint pen with ink. The inkfilled pen is used in order to provide visual feedback and prevent confusion. As focus is on the time spent, time is measured for each row so that the time variation can be used as a measure of vigilance. In addition the number of errors is recorded for each row. The parameters of the test are:

    Perception and attention:

  • Number of missed detections for each row
  • Number of incorrect detections for each row
  • Total number of missed detections
  • Total number of incorrect detections
    Speed:
  • Response time for each row in seconds
  • Total performance time in seconds
  • Median time per line in seconds
    Vigilance:
  • Fluctuation, i.e. the difference in time in seconds between the slowest and the fastest lines

    The last test in the Cognitive Function Scanner system is the Continuous Reaction Time Test composed of a series of audible stimuli each with a constant tone at 440 Hz. The tones are randomly played back with two to six seconds intervals and presented to the subject via headphones. The subject is asked to press a button held in his dominant hand as soon as he hears the tone. When the button is pressed, the tone disappears. A total of 75 stimuli are recorded. The parameters of the test are:

    Perception and attention:

  • Each reaction time in milliseconds
  • Median reaction time in milliseconds
    Vigilance:
  • Fluctuation, i.e. the difference in milliseconds between the slowest and the quickest reactions.

    Output

    In the Cognitive Function Scanner system two different approaches can be used for the evaluation of the examination results, either separately or in combination. In accordance with the psychometric tradition, a subject's test results may be related to reference values derived from a general population sample and adjusted for age, gender and education (N=1026). Or the style of the subject's problem solving strategy may be analyzed qualitatively by relating the content of a response to other responses, response latencies, response stability, etc. in accordance with the process concept of contemporary cognitive psychology (pattern analysis).

    The Cognitive Function Scanner examination is completed with the printing of a series of tables and diagrams. The first table is a summary of the psychometric results and the rest of the tables and diagrams show the response process information. The complete list of result printouts includes the following:

    1. Summary printout table on the main psychometric test parameters
    2. Face Recognition Test, immediate section, response positions and profile of response latencies etc.
    3. Face Recognition Test, retention section, response positions and profile of response latencies etc.
    4. Word Recognition Test, immediate section, response positions and profile of response latencies etc.
    5. Word Recognition Test, retention section, response positions and profile of response latencies etc.
    6. Number Learning, learning process and profile
    7. Number Learning, profile of response latencies
    8. Figure Drawing Test, graphic reproduction of the drawing and the deviation from the target line
    9. Parallelogram Test, response positions (with markings of mirroring, shifting, etc.) and profile of response latencies
    10. Bourdon-Wiersma Test, process profile
    11. Bourdon-Wiersma Test, error matrix
    12. Continuous Graphics Test, process profile (one separate profile for each of the three patterns)
    13. Continuous Graphics Test, full reproduction of the pattern drawn
    14. Continuous Reaction Time Test, profile of response latencies.

    Since the result printout is very extensive in volume only a sample of the summary table is given here. The five columns of figures to the right of the test parameter names contain the actual performance of the subject and the reference values corrected for age, sex and education. The reference values are printed in the grey-shaded columns, and the actual results of the subject are printed in the three remaining white columns, depending on the level of performance. If the performance is better than, or equals, the 50-percentile, the result is printed to left of the 50-percentile column. If the performance falls between the 50-percentile and the 90-percentile, or equals the 90-percentile, the result is printed in the column between the two shaded reference columns. If the performance is poorer than the 90-percentile the result is printed to the right of the 90-percentile column. It means that this summary page can be read as a performance profile with easy identification of the strong and weak sides. For more refined interpretation than allowed by the summary parameters the psychologist is referred to the response process pages following the summary page.

    Below is an example of a Cognitive Function Scanner Result Summary Page. You may download this page in pdf-format and print it in high resolution. No response process page examples are given here because they might give away the answers to the tests.


    Output page # 1