Insomnia Insomnia

Cognitive-Behavioral Therapy 159
Objective Assessment
In current clinical practice, the diagnosis of primary insomnia does not require
an in-laboratory, polysomnographic study to substantiate the diagnosis. This is true
for three reasons. First, there is enough of a general correspondence between the
subjective complaint and objective measures so that polysomnographic assessment
is not required to verify the sleep continuity disturbance. Second, traditional
polysomnography does not reveal, or allow for the quantification of, the underlying
sleep pathophysiologies that presumably give rise to the patient’s complaints. Third,
and most pragmatically, third-party payers will not reimburse for sleep studies on
patients with likely primary insomnia. However, sleep studies are indicated if the
patient demonstrates symptoms consistent with other intrinsic sleep disorders and/
or fails to respond to treatment.
When assessed with polysomnography, patients with primary insomnia reliably
exhibit increased SL, increased FNAs, increased WASO time, and decreased TST
relative to good sleeper controls. Polysomnographic findings, however, do not
correspond in a one-to-one fashion to patient perceptions of sleep continuity.
Patients with insomnia routinely report more severe sleep disturbance than is evident
on traditional polysomnographic measures (28–30). Some have argued that
this discrepancy might be explained by the findings that patients with primary insomnia
show a greater degree of psychopathology, including tendencies to somatize
internal conflicts and exaggerate symptoms (31–33). Others have argued that the
subjective–objective discrepancy findings reflect a cardinal feature of the disorder,
that is, the persistence of sensory and information processing into NREM sleep. The
continuance of such processes into polysomnographic-defined sleep are thought to be
the basis for patient difficulties distinguishing between wakefulness and sleep (3).
The extent to which one or both of these factors contributes to the discrepancies
between subjective and objective measures of sleep in insomnia continues to be a
matter of ongoing debate. (For additional information on these issues, please see the
following section on the cognitive-behavioral perspective on insomnia.)
When polysomnography is not feasible, the use of alternative, less costly objective
devices can be particularly helpful when the clinician suspects a high degree of
SSM. SSM is a term (as well as disorder) used to describe the common finding
among patients with insomnia that there is a discrepancy between a patient’s subjective
impression of sleep parameters and what is measured via objective recording
methods. At the level of self-report, extreme values (gathered retrospectively or
prospectively) may suggest that this is a component of the disorder (e.g., SLs >2
hours, WASO >2 hours, or a TST of ≤4 hours). In the absence of a
polysomnographic study, actigraphs may be used to obtain corroborating prospective
data. Actigraphs are wristwatch-like devices that utilize sophisticated movement
detectors to estimate the traditional sleep continuity parameters (e.g., SL,
WASO, FNA, and TST). This information may, in turn, be compared to the selfreport
data to assess the degree to which SSM is occurring. The extent to which
subjective–objective discrepancies can be resolved using actigraphy has not been