High Quality Content by WIKIPEDIA articles! An altered level of consciousness is any measure of arousal other than normal. Level of consciousness (LOC) is a measurement of a person`s arousability and responsiveness to stimuli from the environment. A mildly depressed level of consciousness may be classed as lethargy; someone in this state can be aroused with little difficulty. People who are obtunded have a more depressed level of consciousness and cannot be fully aroused. Those who are not able to be aroused from a sleep-like state are said to be stuporous.Coma is the inability to make any purposeful response. Scales such as the Glasgow coma scale have been designed to measure level of consciousness.