Table 1

Evaluation of tools for sleep assessment in athletes

Tool	Strengths	Weaknesses	Practicality of use
Objective tools
Polysomnography	Gold standard for sleep assessment. Determination of sleep stages and spectral power. Diagnosis for sleep disorders.	Expensive, intrusive and typically one-time assessment. Typically performed in laboratory in an unnatural sleep environment. Expertise required for interpretation.	Laboratory or home-based systems. Mainly used for sleep disorders diagnosis and research.
Research-grade actigraphy devices	Current standard for sleep assessment in the athletic field setting. Non-intrusive and less expensive than polysomnography. Provides long-term monitoring, provides data on routine. Validated against polysomnography.	Does not measure sleep stages accurately. Not suitable for diagnosis of sleep apnoea. Device is easily removed. Requires expertise for analysis. More expensive than commercial devices. Difficulties with assessing insomnia. Typically overestimate total sleep time and sleep efficiency relative to polysomnography. Some devices do not disclose algorithms.	Affords long-term monitoring in a realistic setting but requires some sleep expertise.
Commercial wearable devices	Non-intrusive and less expensive than polysomnography and research-grade Actigraphs. Provides long-term monitoring and data on routine. Increases sleep awareness, promotes athlete-staff interaction and provides immediate feedback. May prompt further evaluation.	Does not measure sleep stages accurately, unless validation supports this function. Not suitable for diagnosis of most sleep disorders under normal conditions. Device is easily removed. May cause increase in anxiety/worry around sleep. Immediate feedback could influence/be detrimental to performance. Typically overestimate total sleep time and sleep efficiency relative to polysomnography. Most devices do not disclose algorithms or provide access to raw data. Many devices have limited validation.	Affords long-term monitoring in a realistic setting but device must be validated. Ability to adjust feedback important, when required.
Nearables	Non-intrusive, placed on or near the bed, accessible, generally low cost and affords long-term monitoring. May increase sleep awareness, promote athlete-staff interaction and provide immediate feedback. May prompt further evaluation.	Lack of sufficient validation, device not worn by individual, may increase screen time, may increase anxiety/worry around sleep. Immediate feedback could influence/ be detrimental to performance. Little information on algorithms used and most devices do not provide access to raw data.	Lack of validation; therefore, questionable utility.
Subjective tools
Sleep diaries	Non-intrusive and cost effective. Affords long-term monitoring and provides information on routine, subjective information.	Burdensome and may be influenced by recall bias. Overestimates sleep duration and efficiency relative to polysomnography.	Affords long-term monitoring in a realistic setting but takes effort from the athlete and the practitioner to collect the data. For example, Consensus Sleep Diary.
Sleep questionnaires	Cost and time effective, can provide behaviour information.	May be influenced by response bias, lack of standardised data for athletes.	Questionable utility without validation in athletes. For example, PSQI, ISI, KSS, SSS, ESS, SHI, LSEQ, VAS, MEQ, subjective ratings.
Athlete-specific sleep questionnaires	Cost and time effective, can identify athletes who need further sleep assessment, can provide behaviour information, validated in athletes.	May be influenced by response bias, lack of validation with polysomnography.	Can be used as an initial clinical tool (ASSQ), and a way to identify maladaptive sleep behaviours (ASBQ). See figure 2 for specifics. Additional questionnaires needed to be developed for athlete specific assessment.

ASBQ, Athlete Sleep Behaviour Questionnaire; ASSQ, Athlete Sleep Screening Questionnaire; ESS, Epworth Sleepiness Scale; ISS, Insomnia Severity Index; KSS, Karolinska Sleepiness Scale; LSEQ, Leeds Sleep Evaluation Questionnaire; MEQ, Morningness and Eveningness Questionnaire; PSQI, Pittsburgh Sleep Quality Index; SHI, Sleep Hygiene Index; SSS, Stanford Sleepiness Scale; VAS, Visual Analogue Scale.