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In three case-control studies and a household transmission cohort, Danuta Skowronski and colleagues find an association between prior seasonal flu vaccination and increased risk of 2009 pandemic H1N1 flu.

Neuropsychological deficits have been documented in patients with obstructive sleep apnea syndrome (OSAS). Both nocturnal hypoxemia and impairement of daytime vigilance have been suggested as the pathogenesis of these deficits, yet it remains difficult to find good correlations between cognitive deficits and either of these physiological parameters. In the present study, 10 normal controls were compared to 10 moderately and 10 severely apneic patients, all recorded in a sleep laboratory for two consecutive nights, with a vigilance and neuropsychological assessment made during the intervening day. Relative to the controls, moderate and severe OSAS showed differences in many cognitive functions, although the severely affected showed the greater differences. Moreover, severe apneics were also worse than moderate apneics on tests that were found to be normal in the latter group. This suggests a discontinuity in the appearance of neuropsychological deficits as OSAS progresses. Further analyses revealed that reductions in general intellectual measures, as well as in executive and psychomotor tasks were all attributable to the severity of hypoxemia, while other attention and memory deficits were related to vigiance impairment. Therefore, both vigilance impairment and nocturnal hypoxemia may differentially contribute to the cognitive dysfunctions found in OSAS.

The obstructive sleep apnea syndrome is characterized by nocturnal sleep disturbance, excessive daytime sleepiness and neuropsychological deficits in the areas of memory, attention, and executive tasks. In the present study, these clinical manifestations were assessed in apneic patients before and 6 months after treatment with nasally applied continuous positive airway pressure (CPAP). CPAP treatment was found to restore normal respiration during sleep and to normalize sleep organization. Daytime vigilance greatly improved with treatment but some degree of somnolence as compared to normal controls persisted. Similarly, most neuropsychological deficits normalized with treatment. The exception was for planning abilities and manual dexterity, two neuropsychological deficits that have been found to be highly correlated with the severity of nocturnal hypoxemia. These results raise the possibility that anoxic brain damage is a pathogenic factor in severe obstructive sleep apnea syndrome.

There is a lack of data about the practice effect and test-retest reliability (TRR) on many attentional and executive tests in neuropsychology. In this study, 37 subjects aged 52 to 80 were tested three times with an inter-assessment interval of 14 days. The battery included the Rey Auditory Verbal Learning Test, the Stroop interference test, the Letter-Number Sequencing test, Wechsler Adult Intelligence Scale-III (WAIS-III), the Ruff 2 and 7 Selective Attention Test, the Tower of London, the Verbal Fluency test, and simple, choice, and sequential reaction time tests. The results showed that tasks were generally subject to a practice effect, except for those with alternate forms. In all tests, there were a number of scores demonstrating good TRR, but others, although largely used in clinical practice, failed to reach acceptable TRR standards. Usually, time derived scores were associated with the best TRR.

Numerous studies have assessed a wide range of cognitive deficits associated with obstructive sleep apnea syndrome (OSAS). The comparison of these various results, however, is hampered by the fact that different studies employ different neuropsychological tests, even when assessing the same function. The aim of this paper is to present a standardized neuropsychological test battery for the evaluation of OSAS patients. Following a description of the general characteristics of OSAS, we review the main cognitive functions reported as being impaired in OSAS patients. These include general intellectual functioning, attentional functioning, memory and learning abilities, executive functions, and motor performance. Based on this review, we propose a test battery designed to cover these cognitive processes while taking into account the time constraints present in most research and clinical centers. In addition to providing a comprehensive neuropsychological evaluation of OSAS patients, the proposed test battery should facilitate the comparison of results from different laboratories.

Household transmission of pH1N1 may be substantially greater than previously estimated, especially in association with clinical presentations that include gastrointestinal complaints. Approximately 10% of pH1N1 infections acquired in the household may be asymptomatic.

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