RESEHARCH PAPER IN THE UNITED STATES

Patient classification in neuropsychological research

OBJETIVE:

We have argued that in such cases very restrictive conditions
must he met in order to be able to draw valid inferences about the structure of

normal cognitive mechanisms.

Two consequences of these conditions are (I)

patient classification into syndrome types (e.g., phonological dysgraphia. agrammatism,

and so forth) can play no useful role in research concerned with issues

about the structure of normal cognitive functioning or its dissolution under conditions

of brain damage; and (2) only single-patient studies allow valid inferences

about the structure of cognitive mechanisms from the analysis of impaired performance.

In a number of papers we have been concerned with the type of inferences

that are legitimate in “experiments of nature” where the experimenter does not

and cannot control the modifications to the cognitive system that are introduced

by brain damage.