Speed of processing

Reasoning is not just about solving difficult problems, but also about solving them quickly; the difference between power and speed. IQ tests as above do have timed subtests sensitive to speed, but it can be useful to administer specific tests that are not quite so confounded with intellectual ability.

One example, particularly sensitive to even quite mild concussion, is the Paced Auditory Serial Addition Test ( PASAT).(1112) Here, the client is read a list of numbers, and as each one is read out so it has to be added to the previous number and the answer spoken aloud ( Table... .6). This has to be done quickly or the next number will come along. There are several trials in which the numbers are delivered at a faster and faster pace, from one number every 2.4 s down to every 1.2 s. It sounds easy but in actuality is very demanding; even at the slowest speed the average score is only about 70 per cent correct, and this falls away to only about 40 per cent at the fastest speed. Indeed, if a patient has any significant mental slowing, they often cannot do the test at all. Obviously the test cannot be used if the patient has a stammer, or is dysarthric or innumerate.

Table 6 Sample from PASAT

A less stressful test of mental speed is the Speed of Comprehension Test, (!3> in which the person indicates as fast as possible whether simple sentences are true or false (e.g. tomato soup is a liquid, grapes are people). There are four parallel versions, and the test can be given auditorily for patients who cannot read.

Two visual tests of mental speed are Map Search (looking for target symbols on a map as fast as possible) and Telephone Search (looking for various symbols on a page from a telephone directory).(l4> There are three parallel forms.

One test that tries to disentangle the relative contribution of slowed motor speed versus slowed mental speed, often a crucial issue in patients with motor deficits, is the Adult Memory and Information Processing Battery(!5) which has two useful timed tests of cancelling target digits.

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Funny Wiring Autism

Funny Wiring Autism

Autism is a developmental disorder that manifests itself in early childhood and affects the functioning of the brain, primarily in the areas of social interaction and communication. Children with autism look like other children but do not play or behave like other children. They must struggle daily to cope and connect with the world around them.

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