Limitations of cognitive status exams: a case-based discussion

Despite their extensive use in psychiatric and medical settings, brief mental status examinations have significant limitations that are easily overlooked in the pressure-cooker environments within which they are commonly used. Although undoubtedly of value as quick screening devices, the sheer brevity of these instruments all but guarantees limited validity. Brief examinations perform best with grossly impaired cases, alerting clinicians to the fact that something is badly amiss in patients who are significantly confused, disoriented, aphasic, or otherwise severely impaired. Very poor scores are accordingly frequently useful. Moderate or even perfect scores, however, will frequently be misleading, because patients with compromised brains often obtain them (Nelson et al. 1986). One such case follows.