Lenient scoring of spatial orientation errors (SOE) on the Mini-Mental State Exam (MMSE) is common practice, even though it deviates from standard protocol and may compromise its diagnostic power. This study was designed to empirically evaluate the effect of lenient scoring on the MMSE's classification accuracy. Participants were 113 community dwelling older adults recruited for a research study, representing a wide range of range of neurological status from cognitively healthy to Alzheimer's disease. Clinical classification was determined by expert assessors based on multiple sources of clinical evidence. Lenient scoring significantly inflated MMSE total scores (d = .88, large effect), and suppressed failure rates (from 26% to 14%). Standard scoring produced superior overall classification accuracy (75% vs. 67%) over lenient scoring and, more importantly, increased sensitivity from .33 to .53, with minimal loss in specificity (from 1.00 to .95). SOEs are empirical markers of cognitive decline and should not be adjusted based on clinical judgment. Results indicate that diminished sensitivity to cognitive impairment is an unintended consequence of lenient scoring and argue against this practice.
Keywords: Cognitive screening; MCI; MMSE; halo effect; scoring bias; spatial orientation.