Direct support persons (DSPs) often face problems in observing and determining alertness in individuals with profound intellectual and multiple disabilities (PIMD). A literature study was carried out to gather information about the problems just described. A search of two electronic databases and the references found in relevant hits revealed 42 relevant publications. The results show that two types of descriptions of alertness can be distinguished: (1) those with a focus on the individual only or (2) those with a focus on the interaction of individual and environment. Several observation categories were used in the studies that were found. The reliability of the observations turned out to be a core problem in most of the studies. Only a limited number of environmental conditions that were expected to have an impact on alertness in individuals with PIMD were investigated. While modifications of the environment, interaction strategies, stimulation strategies and staff training were found to have a positive impact on alertness, studies about treatment activities led to conflicting results. Finally, we will formulate the resulting implications for future studies and for the development of an instrument for DSPs in order to observe alertness in individuals with PIMD in clinical practice. (Contains 2 figures and 2 tables.)