To evaluate the effect of intermittent hypoxemia on neuropsychological functioning, neuropsychological tests were administered to 14 sleep apnea patients, a control group of 10 patients with other disorders of excessive somnolence, and another control group of 14 healthy volunteers. The sleep disorder groups were matched on two measures of sleepiness. It was found that sleep apnea patients performed significantly worse than both controls on 7 of 14 neuropsychological measures and on a rating of global neuropsychological impairment. The overall level of performance reflected only moderate impairment. Within the sleep apnea group, hypoxemia severity was significantly correlated with deficits on measures of motor and perceptual-organizational ability.
"The majority of studies assessing cognition show spared global cognitive functioning and basic language functions   . By contrast , most OSA patients are impaired on testing of vigilance, that is, tests that require sustained attention for a period of time, a finding which has important implications for the ability to drive and for general occupational functioning    . "
"Mild impairments in short-term verbal (Naegele et al., 1995, 2006; Twigg et al., 2010) and visual (Ferini-Strambi et al., 2003; Naegele et al., 1995) memory have been observed in some studies but not others (Greenberg et al., 1987; Kim et al., 1997). Longterm semantic memory impairment has also been reported (Ferini-Strambi et al., 2003; Salorio et al., 2002), but again the findings are not consistent on all tests (Bedard et al., 1991b; Greenberg et al., 1987; Naegele et al., 1995). Where procedural memory has been investigated, this too has produced inconsistent results (Naegele et al., 2006; Rouleau et al., 2002). "
[Show abstract][Hide abstract] ABSTRACT: Sleep-related breathing disorders encompass a range of disorders in which abnormal ventilation occurs during sleep as a result of partial or complete obstruction of the upper airway, altered respiratory drive, abnormal chest wall movement, or respiratory muscle function. The most common of these is obstructive sleep apnea (OSA), occurring in both adults and children, and causing significant cognitive and daytime dysfunction and reduced quality of life. OSA patients experience repetitive brief cessation of breathing throughout the night, which causes intermittent hypoxemia (reductions in hemoglobin oxygen levels) and fragmented sleep patterns. These nocturnal events result in excessive daytime sleepiness, and changes in mood and cognition. Chronic excessive sleepiness during the day is a common symptom of sleep-related breathing disorders, which is assessed in sleep clinics both subjectively (questionnaire) and objectively (sleep latency tests). Mood changes are often reported by patients, including irritability, fatigue, depression, and anxiety. A wide range of cognitive deficits have been identified in untreated OSA patients, from attentional and vigilance, to memory and executive functions, and more complex tasks such as simulated driving. These changes are reflected in patient reports of difficulty in concentrating, increased forgetfulness, an inability to make decisions, and falling asleep at the wheel of a motor vehicle. These cognitive changes can also have significant downstream effects on daily functioning. Moderate to severe cases of the disorder are at a higher risk of having a motor vehicle accident, and may also have difficulties at work or school. A number of comorbidities may also influence the cognitive changes in OSA patients, including hypertension, diabetes, and stroke. These diseases can cause changes to neural vasculature and result in neural damage, leading to cognitive impairments. Examination of OSA patients using neuroimaging techniques such as structural magnetic resonance imaging and proton magnetic resonance spectroscopy has observed significant changes to brain structure and metabolism. The downstream effects of neural, cognitive, and daytime functional impairments can be significant if left untreated. A better understanding of the cognitive effects of these disorders, and development of more effective assessment tools for diagnosis, will aid early intervention and improve quality of life of the patient.
Progress in brain research 01/2011; 190:53-68. DOI:10.1016/B978-0-444-53817-8.00003-7 · 2.83 Impact Factor
"Although, we observed little impact of OSAH by itself on selected measures of neuropsychological function, hypoxemia was associated with decrements in motor and processing speed performance. In clinical populations, OSAH patients with hypoxemia have been found to be more cognitively impaired than persons without hypoxemia  . Some studies performed in non-clinical samples have also found a relationship between severity of hypoxemia and neuropsychological function  . "
[Show abstract][Hide abstract] ABSTRACT: Obstructive sleep apnea-hypopnea (OSAH) is associated with sleep fragmentation and nocturnal hypoxemia. In clinical samples, patients with OSAH frequently are found to have deficits in neuropsychological function. However, the nature and severity of these abnormalities in non-clinical populations is less well defined.
One hundred and forty-one participants from the Tucson, AZ and New York, NY field centers of the Sleep Heart Health Study completed a battery of neuropsychological tests for 9-40 months (mean=24 months, SD=7 months) after an unattended home polysomnogram. Sixty-seven participants had OSAH (AHI>10) and 74 did not have OSAH (control (CTL), apnea-hypopnea index (AHI)<5). In addition to the individual tests, composite variables representing attention, executive function, MotorSpeed and processing speed were constructed from the neuropsychological test battery.
There were no significant differences in any individual neuropsychological test or composite variable between the OSAH and CTL groups. However, when time spent with O(2) saturations less than 85% was dichotomized into those participants in the top quartile of the distribution and those in the lower three quartiles, motor speed was significantly impaired in those who were more hypoxemic. In addition, poorer motor speed (model adjusted R(2)=0.242, P<0.001) and processing speed performance (model adjusted R(2)=0.122, P<0.001) were associated with more severe oxygen desaturation even after controlling for degree of daytime sleepiness, age, gender and educational level.
Mild to moderate OSAH has little impact on the selected measures of attention, executive function, motor speed and processing speed. However, hypoxemia adversely affects both motor and processing speed. These results suggest that in middle-aged to elderly adults the neuropsychological effects of clinically unrecognized mild to moderate OSAH are neither global nor large.
Sleep Medicine 10/2006; 7(6):498-507. DOI:10.1016/j.sleep.2006.02.005 · 3.15 Impact Factor
Data provided are for informational purposes only. Although carefully collected, accuracy cannot be guaranteed. The impact factor represents a rough estimation of the journal's impact factor and does not reflect the actual current impact factor. Publisher conditions are provided by RoMEO. Differing provisions from the publisher's actual policy or licence agreement may be applicable.