APRAXIA (literally, “inability to act or do”)


Loss of ability to perform purposeful movements or manipulate common objects.This disorder is caused by injury or disease which damages the parietal lobe of the brain. The injury does not produce paralysis or disturbances of sensation, but affects the memory for acts and skills. The apraxic individual cannot remember how to do things he has been doing all his life, such as tying his shoelaces, opening a door, driving a car, or eating with knife and fork. He can recognize objects and move his arms and legs but cannot put movements together into a useful pattern.There are various types of apraxia, each tested by the types of activities mentioned in the following descriptions. In the limb-kinetic type the patient can appreciate and understand the kind of movement he wants to make, such as swinging a tennis racket, but cannot carry it out with accustomed skill. This disorder is usually limited to one limb or one side of the body, and results in extremely clumsy attempts at control. In the idiokinetic type the patient has no difficulty formulating the idea of the act he wishes to carry out, but finds that he is totally unable to execute it. His impulse simply will not translate itself into the appropriate movements. He may, for example, make a fist when he grasps objects automatically, but he cannot make a fist on command. The apraxia may be present on both sides or only on one side of the body. Sometimes the face is affected, and the individual cannot imitate a smile or any other expression at will.Ideational apraxia consists in a failure to perform a complex series of actions because the patient has a distorted conception of the movement as a whole. In trying to light a cigar he might put the match in his mouth and rub the cigar against the matchbox. A person who is afflicted with the constructive type of apraxia, cannot reproduce simple patterns with matchsticks or blocks. An apraxia for dressing appears to be a separate category, sometimes occurring in isolation from the other types. The patient cannot choose or put on his clothes correctly because he is unable to relate the form of the garments to the shape of his body. (This is probably a blend of apraxia and agnosia, the inability to know or recognize objects or language.) See AGNOSIA.APTITUDE TESTS (Multiple). A battery of separate tests designed to measure the basic components of intelligence.Multiple aptitude tests are based on three observations. First, intelligence tests do not always measure the same abilities, and therefore an individual may score differently on different tests; second, some of the abilities measured on intelligence tests appear to be relatively independent aptitudes, since an individual might do consistently better on one part of the test than on another; and third, the usual intelligence tests do not cover every important intellectual function. As a result of these observations, psychologists have sought to identify all the basic abilities involved in intelligence. In so doing, they applied a procedure known as factor analysis, which consisted of three basic steps: (a) administration of tests on different functions to the same person; (b) a determination of the intercorrelations among the resulting scores; and (c) statistical analysis of the correlations to discover which abilities tended to cluster together and which were relatively independent.When the basic abilities, or factors, were identified, aptitude tests were devised to measure them. Although different investigators have offered different combinations of tests, and different test items, the common purpose of multiple aptitude tests is to provide a more balanced and comprehensive measure of intelligence. To show the subject’s strengths and weaknesses most graphically, a profile of scores rather than a single global I.Q. is computed.the following batteries are in wide use today. (Sample items are not given here, since they are similar to those described under tests for intelligence and special aptitudes).SRA Primary Mental Abilities {PMA) (Ages 5 to 7, 7 to 11, 11 to 17). These batteries are an outgrowth of Thurstone’s Chicago PMA Tests (1941), which were based on his analysis of mental abilities into verbal comprehension, word fluency, number, space, as sociative memory, perceptual speed, and general reasoning. The SRA tests do not include all these factors in every battery. Research has shown that the tests for ages five to seven have little value since multiple aptitude batteries are ineffective in the primary level—in fact, differentiation of the child’s abilities does not progress far enough to justify their use below the high school level. Critics find that the current batteries have a number of other serious weaknesses. They are oversimplified, depend excessively on speed, and do not present adequate normative or validity data. Their chief value is in illustrating Thurstone’s factor theory.Differential Aptitude Tests {DAT) (Ages 8 to 12, and unselected adults). Developed primarily for use in educational and vocational counseling, these tests yield scores for eight factors: verbal reasoning, numerical ability, abstract reasoning {Fig. 3), space relations {Fig. 4), mechanical reasoning {Fig. 5), clerical speed and accuracy, spelling,Fig. 4. Space Relations. Which of the figures on the right could be made by folding the given pattern?Fig. 5. Mechanical Reasoning. If the driver turns in the direction shown, which way will the pulley at “X” turn?and sentence usage. Norms are based on a representative national sample, and reliability coefficients are high. A tremendous amount of validity data is available, most of which shows relatively high correlations with performance in high school and college. A combination of the scores on two of the tests, verbal reasoning and numerical ability, correlates so highly with grades that it may be effectively used as an intelligence (or at least a scholastic aptitude) test. The authors advocate a clinical rather than a statistical interpretation of scores, and in a case book, Counseling From Profiles, they show how they can be utilized in guiding students.Flanagan Aptitude Classification Tests (FACT). Designed mainly for vocational counseling and employee selection, this battery is based on twenty-one “critical job elements” identified through job analysis. These elements were chosen because they differentiated successful from unsuccessful workers on a variety of jobs. Tests were then created to measure each of the elements—for example, the “assembly” item shows parts of objects (Fig 6), and the subject selects one of five pictures in which they are correctly assembled. Some of the other elements are ingenuity, planning, carving, and tapping. See JOB ANALYSIS.Norms have been established for grades nine to twelve, and the scores have been combined into thirty-eight occupational aptitude scores, including a score for general college aptitude, and scores for occupations ranging from plumber to humanities teacher. The reliabilities of the composite scores are higher than those for the individual tests, but they show considerable overlapping. This is to be expected for occupations as closely related as telephone operator and office clerk, which correlate .90, but not for airplane pilot and draftsman, which nevertheless have been found to correlate .95. The battery has proven effective in predicting success in occupational training, but there is as yet an insufficient amount of data on its ability to predict success on the job itself.Guilford-Zimmerman A ptitude Survey. Constructed for counseling and personnel classification, this battery includes tests for (1) verbal comprehension, (2) general reasoning, (3) numerical operations, (4) perceptual speed, (5) spatial orientation, (6) spatial visualization, and (7) mechanical knowledge. Tests 1 and 2 can be combined to yield a score for abstract intelligence; 3 and 4 for clerical aptitude; and 5, 6, and 7 for mechanical aptitude. Two spatial tests are used because orientation isFig. 6. Assembly. Which is the correct assembly of the parts at the left?necessary for such operations as piloting a plane or running a machine, while visualization is involved in picturing objects as they would be when tilted or rotated. So far, validity studies show substantial correlations of tests 1 and 2 with grades in most courses, while scores on the numerical and space tests correlate with mechanical or scientific learning and with success in industrial training. Evidence of predictive validity for different occupations has not been offered.Holzinger-Crowder Uni-Factor Tests. Based directly on factorial analysis, this battery provides tests for four sharply defined functions: verbal, spatial, numerical, and reasoning. The battery meets all technical requirements, and the norms are based on a large national sample of junior and senior high school students. The manual gives directions for combining the factor scores to predict general scholastic aptitude and performance in science, social studies, English, and mathematics. Evidence on differential validity is promising, and the tests are therefore considered useful in selecting educational and vocational areas.Multiple Aptitude Tests [MAT). This battery presents nine well-constructed tests that yield scores in verbal comprehension, perceptual speed, numerical reasoning, and spatial visualization. The procedures for scoring and for evaluating resulting profiles are carefully handled. Like the DAT, the test is designed primarily for counseling, but there is as yet insufficient data on its effectiveness in predicting school grades or occupational performance.General Aptitude Test Battery (GATB). Developed by the United States Employment Service for use by state employment counselors, this battery is the result of factorial analyses of preliminary tests given to large groups of trainees in vocational courses. After repeated revisions, the tests have been reduced to twelve, and the factors tothe following nine: intelligence (computed by adding the scores on the next three tests), verbal aptitude, numerical aptitude, spatial aptitude, form perception, clerical perception, motor co-ordination, finger dexterity,manual dexterity. The nine scores can be converted into standard scores, and can therefore be compared.By testing large groups of employees and trainees, occupational ability patterns (OAP’s) have been established, against which an individual’s profile score can be matched. For instance, plumbing requires a minimum score of 85 for intelligence and 80 for numerical aptitude, spatial aptitude, and manual dexterity. The OAP’s so far developed cover over five hundred occupations, and the test is now used in counseling about a half million applicants each year, not only in State Employment offices but in colleges, VA hospitals, prisons, and other nonprofit organizations. A huge amount of validity data has been reported in the Validity Information Exchange published in Personnel Psychology.In general, the GATB is considered highly effective, although it has certain limitations: the tests are greatly speeded, mechanical comprehension is omitted, and reasoning and creativity do not receive sufficient attention.Employee Aptitude Survey Test Series. This battery consists of ten brief, easily administered business and industry tests validated against performance on different jobs: the Verbal Comprehension Test, for executive and high- level office workers; the Numerical Ability Test, for supervisors, accountants, clerical workers; the Visual Pursuit Test (tracing lines), for draftsmen, checkers, technicians; the Visual Speed and Accuracy Test, for bookkeepers, stenographers, machine operators; the Space Visualization Test, for engineers, draftsmen, technicians; the Numerical Reasoning Test, for technical and supervisory positions; the Verbal Reasoning Test, for administrative and technical decision-making positions; the Word Fluency Test of Oral and Written Expression, for journalists, salesmen, secretaries, executives; the Manual Speed and Accuracy Test, for clerical workers, technicians, and machine operators; and the Symbolic Reasoning Test, for data-programmers, accountants, engineers, and other high-level personnel.

Cite this page: N., Sam M.S., "APRAXIA (literally, “inability to act or do”)," in PsychologyDictionary.org, November 28, 2018, https://psychologydictionary.org/apraxia-literally-inability-to-act-or-do/ (accessed December 4, 2021).


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