tors can contribute to insomnia.
The increased prevalence of insomnia in olde r adults is partly explained by the higher
incidence of physical health problems with aging. Changes in sleep patterns associated with
the normal developmental process must be diff erentiated from those exceeding age-related
changes. Although polysomnography is of limit ed value in the routine evaluation of in-
somnia, it may be more useful in the differen tial diagnosis among older adults because the
etiologies of insomnia (e.g., sleep apnea) are more often identifiable in older individuals.