Sleep is important for neural plasticity, and plasticity underlies sleep-dependent memory consolidation. It is widely appreciated that protein synthesis plays an essential role in neural plasticity. Studies of sleep-dependent memory and sleep-dependent plasticity have begun to examine alterations in these functions in populations with neurological and psychiatric disorders. Such an approach acknowledges that disordered sleep may have functional consequences during wakefulness. Although neurodevelopmental disorders are not considered to be sleep disorders per se, recent data has revealed that sleep abnormalities are among the most prevalent and common symptoms and may contribute to the progression of these disorders. The main goal of this review is to highlight the role of disordered sleep in the pathology of neurodevelopmental disorders and to examine some potential mechanisms by which sleep-dependent plasticity may be altered. We will also briefly attempt to extend the same logic to the other end of the developmental spectrum and describe a potential role of disordered sleep in the pathology of neurodegenerative diseases. We conclude by discussing ongoing studies that might provide a more integrative approach to the study of sleep, plasticity, and neurodevelopmental disorders.

Risk factors for the onset of cognitive impairment in Costa Rica are not well understood, despite a substantial elderly population stemming from a higher than average life expectancy for the western hemisphere. To investigate the risk factors that predict the onset of cognitive impairment in the rural elderly of Costa Rica, a modified version of the Mini Mental State Exam—designed for illiterate populations—was administered to 90 elderly inhabitants of San Carlos, Alajuela, Costa Rica between April and May of 2011. Subsequently, each participant took a structured interview assessing viability of risk factors and behaviors potentially contributing to a diagnosis of cognitive impairment. Results showed strong dependencies between age (p=0.0001), education level (p=0.0095), the ability to read (p=0.0001) and write (p=0.0153), frequency of reading (p=0.0011), use of puzzles and mind games (p<0.0001), vocation (p=0.0225), area of residence (p<0.0001), comorbid mental diseases (p=0.0005), history of stroke or brain trauma (p=0.0104), urinary or renal problems (p=0.0443), consistent cooking practices (p=0.0262) and number of living companions (p=0.0299) in susceptibility for developing cognitive impairment. The study concluded that high intellectual use, or lack thereof, during the lifetime of a person was a predictor for cognitive status later in life. In addition, comorbid mental disorders, including neurological trauma due to stroke, impeded normal cognitive function. Future research should examine incidence and risk factors of cognitive impairment in urban, more educated populations. Jeffrey L. Nadel Diana Ulate Associated Colleges of the Midwest, San Pedro Montes de Oca, Costa Rica; jeffrey.nadel@gmail.com, acmcostarica@acm.edu