Number connection test and continuous reaction times in non-encephalopathic patients: a comparative study

Number Connection Test (NCT) and Continuous Reaction Times (CRT) were determined in 94 hospitalized patients with no previous or actual cerebral dysfunction. By NCT, 47 patients used more than 30 s which is the upper normal limit. Of these, 5 used more than 50 s. Two patients exhibited a CRT exceeding the upper normal limit of 240 ms. Thus, accepting the upper limits quoted, one-half of the patients were falsely classified as encephalopathic by NCT, but only 2% by CRT. This indicates that the NCT is too unspecific to exclude encephalopathy and suggests that the CRT is a more valid measure in this respect.