Activities of daily living (ADL) are common human activities, specifically excluding work. They include self-care, communication, physical activity, sensory function, travel, and sleep (1).

These terms are considered together because they all have in common the requirement for the physician to offer an opinion regarding the cause or influences on the cause of the impairment.

Apportionment is defined as a proportional distribution. Apportionment is done when more than one identifiable factor plays a role in causation of impairment. In these situations the physician may be asked to apportion the relative weight of each factor. Often this is difficult, and a best estimate must suffice.

An example of a case using apportionment is an individual with preexisting knee arthritis and minimal difficulty who then sustains a tibial plateau fracture and subsequently requires a total knee replacement. In this situation the physician might apportion the need for knee replacement as 25% due to a preexisting problem and 75% trauma-induced.

There are situations in which the physician can come to no reasonable conclusion regarding apportionment; in that case, he or she should just state that there are multiple factors and let the authorities work it out themselves. Some states do not have an apportionment statute (i.e., if an individual is injured, the judicial system handles the case as if there were no preexisting or concomitant factors), but that is not the physician’s worry. Let the attorneys and judges handle it.

Aggravation in the impairment-rating setting refers to a factor that worsens a medical condition or impairment. An aggravation may be temporary or permanent. In the treatment of an ongoing workers’ compensation case in which aggravation of a preexisting condition is involved, it is quite important to make the determination that a worker has reached maximum medical improvement. Consider the following statement from a
medical examiner: “The aggravation of the preexisting condition was temporary, and the claimant has returned to his preinjury status.” This commentary allows the authorities to move forward with bringing the matter to a conclusion. It also shows the mark of an experienced physician as well as one who has the courage of his or her convictions.

Causation is an identifiable factor that results in a medically identifiable condition (1). Most of the time causation is straightforward; on occasion, however, it can become an issue when multiple causalities are involved. In that situation the physician is called upon to state an opinion as to their relevance.