Gamaldo Charlene E, Benbrook Amy R, Allen Richard P, Oguntimein Oluwamurewa, Earley Christopher J
Johns Hopkins University School of Medicine, Department of Neurology, 5501 Hopkins Bayview Circle, Room 1B.75, Baltimore, MD 21224, United States.
Sleep Med. 2008 Jul;9(5):500-5. doi: 10.1016/j.sleep.2007.07.014. Epub 2007 Sep 14.
Restless legs syndrome (RLS) is a common sensorimotor disorder that peaks in severity during the night and comes on with rest. As a result, this condition often results in significant chronic sleep loss, especially for those with severe disease. Chronic partial sleep restriction has been associated with conditions such as depression, anxiety, chronic pain, and decline in cognitive function. Furthermore, studies have found that RLS patients suffer from these conditions more than their unaffected peers. Thus, the morbidity rate associated with RLS has often been attributed to the chronic sleep loss that frequently accompanies this condition. However, no study has specifically compared RLS sufferers to otherwise normal sleep-restricted controls in order to assess disease morbidity independent of its sleep deprivation effects. In this study, we compared the cognitive function of RLS patients who were off treatment to sleep-restricted control subjects.
A novel chronic partial sleep-restriction protocol that utilized a 14-day combined inpatient and outpatient design was implemented in order to test the differences in cognitive functioning between RLS patients and sleep-restricted controls. The brief cognitive battery included instruments assessing general intelligence and global executive function in order to control for baseline cognitive function between the groups, and then the effects of sleep loss were assessed using prefrontal lobe-specific tasks. The final sample consisted of 16 RLS (11 male and 5 female) and 13 sleep-restricted control subjects (7 male and 6 female).
In order to examine the differences in cognitive functioning between sleep-restricted controls and RLS subjects, independent samples t-tests were conducted. RLS subjects performed significantly better on both the Letter Fluency (t=2.13, p<0.05) and Category Fluency (t=2.42, p<0.05) than sleep-restricted controls.
RLS subjects performed better than the sleep-restricted controls on two tasks that are particularly sensitive to sleep loss. Although previous studies suggest that sleep deprivation may impact the cognitive function of those with RLS, our data suggests that RLS subjects may show a relative degree of sleep loss adaptation. Future investigations that more closely match the sleep loss pattern of RLS subjects to controls are warranted in order to explore these potential traits further.
不宁腿综合征（RLS）是一种常见的感觉运动障碍，夜间病情严重程度达到峰值，休息时发作。因此，这种疾病常导致严重的慢性睡眠不足，尤其是对于重症患者。慢性部分睡眠限制与抑郁症、焦虑症、慢性疼痛和认知功能下降等疾病有关。此外，研究发现RLS患者比未受影响的同龄人更容易患这些疾病。因此，与RLS相关的发病率通常归因于这种疾病常伴随的慢性睡眠不足。然而，尚无研究专门将RLS患者与正常的睡眠受限对照组进行比较，以评估独立于睡眠剥夺影响的疾病发病率。在本研究中，我们比较了未接受治疗的RLS患者与睡眠受限对照组的认知功能。
实施了一种新颖的慢性部分睡眠限制方案，该方案采用14天住院与门诊相结合的设计，以测试RLS患者与睡眠受限对照组在认知功能上的差异。简短的认知测试组合包括评估一般智力和整体执行功能的工具，以控制两组之间的基线认知功能，然后使用前额叶特定任务评估睡眠不足的影响。最终样本包括16名RLS患者（11名男性和5名女性）和13名睡眠受限对照受试者（7名男性和6名女性）。
为了检查睡眠受限对照组与RLS受试者在认知功能上的差异，进行了独立样本t检验。RLS受试者在字母流畅性（t=2.13，p<0.05）和类别流畅性（t=2.42，p<0.05）方面的表现均显著优于睡眠受限对照组。
在对睡眠不足特别敏感的两项任务中，RLS受试者的表现优于睡眠受限对照组。尽管先前的研究表明睡眠剥夺可能会影响RLS患者的认知功能，但我们的数据表明RLS受试者可能表现出相对程度的睡眠不足适应性。有必要进行进一步的研究，使RLS受试者与对照组的睡眠不足模式更紧密匹配，以进一步探索这些潜在特征。
