Psychological disturbances that patients may experience during admission to intensive care units (ICUs) can have distressing implications for their emotional and physical integrity, progress and subsequent recovery. It is widely believed by practitioners and reflected in professional literature that these disturbances are precipitated by sensory deprivation or overload in the physical environment of intensive care units. In this paper the sources and mechanism of the sensory imbalances experienced by these patients are examined. A new concept--sensoristrain--has been developed in an attempt to promote awareness and improve understanding of the phenomenon among nurses. Once this has been achieved, assessment and identification of patients at risk are optimized and appropriate interventions can be formulated. Using an eclectic approach to analyse sensoristrain, both causes and effects of the phenomenon have been identified from the literature. This information has been combined with practical examples in the development of a model of the concept sensoristrain. The paper concludes by outlining the resulting implications for nursing practice, which may be used to guide future research both in concept development and identification of effective prevention of the phenomenon conceptualized and interventions if it occurs.