Although objective and subjective methodsof evaluation both exist, we are not aware
of sleep evaluations that successfully measure the invisible experience of parental sleep
loss in the postpartum period generated from an internal or‘emic’perspective. Thefinal
section of the chapter presents narrative data from several focus groups of mothers
caring for infants under a year old. We use these data to propose the need for a novel
instrument to capture key elements of the Baby-Lag phenomenon and offer suggestions
for the development of such a tool.
Objective Methods for Assessing Tiredness and Fatigue:
Can We Objectively Measure the Experience of Parental
Sleep Loss, Tiredness, or Fatigue?
Tiredness and fatigue are slippery concepts, difficult to defineandevenmoredifficult to
objectively measure as variables that can beincluded when building a statistical model.
Existing methods for objective measurement of sleep loss and tiredness have been
developed for use in two key populations: clinical populations where‘tiredness’is
related to pathological conditions such asinsomnia or sleep apnea, and workforce
populations where assessment is conducted for workplace safety monitoring or research
relating to shift work and circadian disruption. Methods for assessing sleep loss and
tiredness in these contexts encompass two main approaches:
(a) those that examine the amount and nature of sleep disturbance or disruption by
examining the quantity and quality of sleep obtained; and
(b) those that assess the consequences for daytime functioning of sleep disruption
or deprivation.Although subjective methods for measuring fatigue have been developed in
clinical and workforce domains, and objective tests of mental fatigue are used in
workforce monitoring, no objective methods for assessing clinical aspects of fatigue
are available as yet, and no methods have been validated for or systematically
applied to early parenting.
Objective Measures of Sleep, Sleep Loss, and Sleep Quality
To provide the relevant background for understanding sleep loss, tiredness, and
fatigue, we begin here by summarizing the methods used to obtain objective
measures of sleep itself. These primarily involve measurement of sleep quantity
(using polysomnography, electroencephalography, and actigraphy), and we discuss
the relevance of these methods to assessing sleep quality. We then examine the
objective methods available to measure the consequences of sleep disruption or
deprivation. These latter methods commonly involve the standardized assessment
30 A.E.F. Rudzik and H.L. Ball