a shorter 10-itemPostpartum Fatigue Scalethat eliminated items that might be
associated with other postpartum issues and not be related to fatigue. The 10-item
scale breaks into two subscales, one of symptoms of physical fatigue and the other
of mental fatigue (Milligan et al. 1997 ). Rychnovsky and Hunter ( 2009 ) used a
modified version of the scale with postpartum women in which respondents gave
responses to the same 30 symptoms on a four-point Likert scale (not at
all/sometimes/moderately so/very much so).
Scales Designed for Use with Clinical Populations
In reviewing research on parental postpartum sleep, it is apparent that several scales
that were initially developed for use in clinical populations have been inappropri-
ately applied to normal healthy populations of postpartum parents. TheEpworth
Sleepiness Scale(ESS) is designed to assess sleepiness in various day-to-day sit-
uations, as experienced‘in recent times’. Consisting of 8 items evaluated on a
4-point Likert scale, the scale is primarily validated for detecting serious sleep
pathologies, such as obstructive sleep apnea, narcolepsy, and hypersomnia (Johns
1991 ) and was developed with the population of older adults in mind, rather than
the postpartum population. Though data on non-clinical populations has been
collected using this scale, it is not the most appropriate choice to measure sleepiness
in a healthy population of parents in the postpartum period. ThePittsburgh Sleep
Quality Index (PSQI) is a very commonly used multidimensional subjective
instrument used to determine quality of sleep. It combines recalled data on times of
sleep and waking, hours of sleep, and time to fall asleep, with 4-point Likert ratings
of 15 items related to sleep quality (Buysse et al. 1989 ). However, the PSQI was
developed to identify abnormal sleep in the geriatric population, and therefore is not
necessarily appropriate for use with healthy parents without a history of sleep
problems, though it has been used for this purpose in several studies. TheStanford
Sleepiness Scale(SSS) is a unidimensional scale designed to assess how alert the
respondent is feeling at the moment of assessment. It consists of a single scale with
7 options, ranging from‘feeling active’to‘no longerfighting sleep’(Hoddes et al.
1972 ). One group of researchers has applied the scale to parental sleepiness (Insana
and Montgomery-Downs 2010 ; Insana et al. 2011 ; Insana and Montgomery-Downs
2013 ).
Perceived sleep estimatesare sometimes used instead of, or in addition to, a
subjective scale. These include recall questions, such as‘how long were you
awake?’and‘how many times did you wake?’(Insana et al. 2011 ).Sleep diaries
are designed to obtain more in-depth perceived sleep estimates (Mueller et al.
2011 ). In research addressing parent–infant sleep, the respondentfills in a log that
indicates periods of sleep, usually both for the parent and for the infant (Ball 2002 ).
Sleep diaries are frequently used in combination with actigraphy, which, as dis-
cussed above, is an objective sleep measure based on the measurement of move-
ment. Sleep diaries offer an important corrective for actigraphy, in that information
3 Baby-Lag: Methods for Assessing Parental Tiredness and Fatigue 37