Measuring recovery from post traumatic amnesia.

Three groups of participants were assessed. Each participant was tested on 20 occasions. The groups comprised people (i) in post traumatic amnesia (PTA) following severe head injury (n=9), (it) with severe head injury but not in PTA (n=10), and (iii) with no history of head injury or other neurological condition (n=13). Subjects were given several tests of memory, attention and learning in order to determine which tests were good at (a) distinguishing people in PTA from those not in PTA, and (b) monitoring recovery over time. The results indicate that people in PTA have a wide range of deficits and their cognitive recovery is a gradual process rather than an all-or-none phenomenon. In terms of measurement, the study suggests that a good test of PTA should include orientation questions, together with a reaction time measure, a visual recognition test and a speed of information processing measure. Most of the tests administered were good at distinguishing between brain-injured and nonbrain-injured people, although only two tests distinguished between the two brain-injured groups, i.e. those in PTA and those out of PTA. Almost all tests were good at monitoring recovery from PTA.