Table 1.

Comparison of clinical features associated with coma, vegetative state, minimally conscious state, and locked-in syndrome

ConditionConsciousnessSleep/wakeMotor functionAuditory functionVisual functionCommunicationEmotion
ComaNoneAbsentReflex and postural responses onlyNoneNoneNoneNone
Vegetative stateNonePresentPostures or withdraws to noxious stimuliStartleStartleNoneNone
Occasional nonpurposeful movementBrief orienting to soundBrief visual fixationReflexive crying or smiling
Minimally conscious statePartialPresentLocalizes noxious stimuliLocalizes sound locationSustained visual fixationContingent vocalizationContingent smiling or crying
Reaches for objectsInconsistent command followingSustained visual pursuitInconsistent but intelligible verbalization or gesture
Holds or touches objects in a manner that accommodates size and shape
Automatic movements (e.g., scratching)
Locked-in syndromeFullPresentQuadriplegicPreservedPreservedAphonic/AnarthricPreserved
Vertical eye movement and blinking usually intact