Periodic limb movement disorder (PLMD) is a sleep-related movement disorder characterized by involuntary, rhythmic limb movements during sleep. While PLMD itself is not considered life-threatening, its association with certain underlying health conditions raises concerns about mortality risks. PLMD has been found to be associated with cardiovascular diseases such as hypertension and cardiovascular disease. The fragmented sleep caused by the repetitive limb movements and associated arousals may contribute to sympathetic activation, chronic sleep disruption, sleep deprivation, and subsequent cardiovascular problems, which can increase mortality risks. The comorbidities and health factors commonly associated with PLMD, such as obesity, diabetes, and chronic kidney disease, may also contribute to increased mortality risks. PLMD is often observed alongside other neurological disorders, including restless legs syndrome (RLS) and Parkinson's disease. The presence of PLMD in these conditions may exacerbate the underlying health issues and potentially contribute to higher mortality rates. Further research is needed to elucidate the specific mechanisms linking PLMD to mortality risks and to develop targeted interventions that address these risks.

Periodic limb movements during sleep (PLMS) are prevalent in various sleep disorders, such as restless legs syndrome (RLS), periodic limb movements disorder, obstructive sleep apnea (OSA), REM sleep behavior disorder (RBD), and narcolepsy. PLMS has been hypothesized to be related to the decline of dopaminergic transmission. In RLS, PLMS is suggested to be related to iron deficiency and symptom severity. PLMD is a rare sleep disorder, and the role of PLMS in PLMD has not been clearly investigated yet. PLMS in OSA, which remain after proper PAP therapy, may need further management. The clinical relevance of PLMS in RBD and narcolepsy have not been investigated thoroughly and need further studies. Whether PLMS are to be considered as a mere symptom of individual sleep disorders or not can be elucidated through studies investigating the efficacy of therapeutic approaches to reduce PLMS in various sleep disorders.

The Seasonal Affective Disorder (SAD) is a disorder characterized by prolonged periods of depression and various physical and psychological symptoms experienced during specific seasons, typically winter. In this review aims to provide a comprehensive overview of SAD with a specific focus on psychophysiological aspects. Through the review from ancient times to the present, this paper explores the characteristics, causes, and underlying mechanisms of SAD. Particularly, it comprehensively reviews the research findings on the relationship between external factors such as light, sunlight, climate, and their association with SAD. Furthermore, the paper discusses the interplay between SAD and psychophysiological changes, along with the latest research trends in treatment and prevention strategies. By combining theoretical and practical perspectives on SAD, this article aims to provide a holistic understanding and offer suggestions for future research directions and clinical interventions.

목 적: 본 연구에서는 불면증상 뿐만 아니라 과다수면, 하지불안증후군을 포함하여 수면 문제를 포괄적으로 평가하기 위한 수면 문제 선별 설문지(Sleep Problem Screening Questionnaire, SPSQ)를 개발하고, 신뢰도와 타당도를 검증하고자 하였다. 방 법: 불면증상(SPSQi), 과다수면(SPSQh), 하지불안증후군(SPSQr)의 세 가지 하위 영역을 포함하는 SPSQ를 개발하였다. 다음으로, 불면장애 임상군 222명 및 건강군 78명을 대상으로 SPSQ와 비교 척도인 불면증 심각도 척도(Korean version of Insomnia Severity Index)를 진행하고, 해당 데이터를 분석에 사용하였다. 결 과: SPSQ는 수용할만한 내적 일관성과 수렴·변별 타당도를 보여 수면장애의 측정에 타당한 도구로 평가되었다. ROC curve 분석 결과, 불면장애의 임상적 유의미성 판단을 위한 절단점은 SPSQi 6점, 민감도와 특이도는 각각 0.94, 0.96이었다. 결 론: 해당 연구결과는 SPSQ가 일반 성인 인구의 수면 문제를 선별하는데 있어 신뢰할 수 있고 유효한 도구임을 시사한다. 단, 하지불안증후군 및 과다수면 관련 척도와 비교 검증이 수행되지 못한 점을 고려해야겠다.