Objective Measures of Sleepiness and Wakefulness: Application to the Real World?

Abstract

The impact of excessive sleepiness on the individual and on society is immense, and chronic sleepiness is one of the most common complaints evaluated by sleep medicine specialists. The author explores how measures of sleepiness and wakefulness using the Multiple Sleep Latency Test (MSLT) and the Maintenance of Wakefulness Test (MWT) can be clinically useful. A companion article presents a counterpoint discussion of the limitations and drawbacks associated with the MSLT and MWT. Both presentations use an evidence-based approach to understanding the operating characteristics of these tests, and the overall goal is to clarify for sleep medicine specialists the positive and negative attributes of the MSLT and MWT. The MSLT and MWT are the most widely accepted objective measures of an individual's ability to fall asleep and ability to remain awake, respectively. The MSLT is a well-validated and extensively published objective measure of the speed at which a subject falls asleep under standardized laboratory conditions, and it is associated with good to excellent interrater and intrarater reliability, and excellent test-retest reliability. The MSLT is indicated as part of the evaluation of suspected narcolepsy and it may be helpful in differentiating narcolepsy from idiopathic hypersomnia. Mean sleep latency values less than 5 minutes are observed in the majority of subjects with narcolepsy, and the presence of two or more sleep-onset rapid eye movement periods is strongly correlated with a diagnosis of narcolepsy. An MSLT should be performed to address specific clinical questions, and should not be used as a screening tool. The MWT has clinical usefulness in evaluating response to treatment following intervention for conditions associated with excessive sleepiness, and in assessing individuals who must remain awake for safety reasons. However, the sleep medicine specialist should not rely solely on mean sleep latency values as a single indicator of impairment or risk of accidents, but findings should be integrated with the clinical history, compliance, patient judgment, and other factors to form a global impression regarding the individual's response to treatment. Future challenges include refinement of normative ranges in different populations using rigorous statistical methods, and improved understanding of the specific operating characteristics of the MSLT and MWT in different age groups. Additional study is necessary regarding the impact of MSLT and MWT findings on clinical decision-making, patient outcome, and patient and physician satisfaction. From a safety and regulatory standpoint, additional study is needed to establish the correlation between MWT findings and the risk of adverse consequences of sleepiness such as accidents. Because the MSLT and MWT are in-laboratory tests, it is important that investigators also develop novel techniques that provide reliable assessment of sleepiness and wakefulness in the actual work environment over extended periods. In summary, the MSLT and MWT are not perfect tests, but ...

Impact of obstructive sleep apnea on cognitive performance

“…Previous studies investigating cognitive performance in patients with OSA have been able to distinguish the impairment resulting from EDS from that determined by chronic obstructive pulmonary disease, which traditionally assumes the occurrence of ischemic prefrontal lesions [21][22][23] .…”

Diretrizes brasileiras para o diagnóstico de narcolepsia

“…68,69 It is not a diagnostic test for narcolepsy and the American Academy of Sleep Medicine recommends the MWT to evaluate 65 the capacity of a patient to remain awake when there is a safety risk to the patient or others 66,67 and to determine the response to treatment in patients with ES 66,67 5) Conclusions of the neurophysiological evaluation The PSG and MSLT are useful to confirm the narcolepsy diagnosis. If PSG followed by the MSLT is negative on separate occasions, the diagnosis of ES due to narcolepsy is excluded.…”

“…Sleep fragmentation associated with OSA can cause false-positive results in the MSLT. 65,66 c) Indications for MSLT repetition in narcolepsy: 67 • first test affected by external circumstances or inadequate study conditions;…”

Estudo da capacidade de manter o alerta em pacientes com fibromialgia por meio do teste da manutenção da vigília

“…A sonolência diurna excessiva pode ser investigada por meio de questionários como o de Epworth (7) . No entanto, a avaliação tem maior acurácia quando são utilizados exames objetivos como o teste das múltiplas latências do sono (TMLS) e o teste da manutenção da vigília (TMV) (8)(9)(10)(11)(12)(13)(14) . No entanto, deve-se considerar que fatores psicológicos podem influenciar as metodologias disponíveis para a avaliação da sonolência diurna, em especial fatores motivacionais e penalidades (14) .…”

“…No entanto, a avaliação tem maior acurácia quando são utilizados exames objetivos como o teste das múltiplas latências do sono (TMLS) e o teste da manutenção da vigília (TMV) (8)(9)(10)(11)(12)(13)(14) . No entanto, deve-se considerar que fatores psicológicos podem influenciar as metodologias disponíveis para a avaliação da sonolência diurna, em especial fatores motivacionais e penalidades (14) . Tendo como hipótese que distúrbios do sono na fibromialgia e a queixa de sono não reparador podem acarretar redução da capacidade de alerta, propõe-se este estudo no sentido de avaliar esse aspecto em pacientes com fibromialgia por meio do TMV.…”