The authors evaluated the 60-Second Test (SST), a brief test of mental concentration, as a supplement to the Glasgow Coma Scale (GCS) for monitoring verbally responsive patients in the neuro-intensive care unit. The SST demonstrated excellent reliability and was abnormal in 79% of patients assigned a top GCS score of 15. However, both tests had poor responsiveness to clinically identified changes in level of consciousness (LOC). The SST is sensitive to subtle alterations in LOC but, like the GCS, may have limitations as a monitoring tool in the neurocritical care setting.