|
| Study | Sample characteristics | Type of study | Results |
|
| Quan et al. 2006 [7] | 67 patients, age = 59.4 ± 9.2,
AHI = 22.4, AHI > 10, 74 healthy controls | Case—control study | Mild to moderate OSAS has little impact on the selected measures of attention, executive function, and motor and processing speed. |
|
| Mathieu et al. 2008 [8] | 28 patients, two age groups, Group A: <50 yr, AHI = 50.8 ± 4.1, Group B: >50 yr, AHI = 42.5 ± 4.1, 30 healthy controls | Case—control study | OSAS patients exhibit attention and verbal long-term memory dysfunctions. Short-term memory, working memory, and planning and flexibility appeared well preserved. OSAS patients showed some difficulty in the initial acquisition of the procedural skill but no procedural skill-learning deficit over time. |
|
| Lim et al. 2007 [53] | 46 patients; 14 patients (OSAS treated with placebo), age = 48.9 ± 3.2, AHI = 65.8 ± 8.2; 17 patients (OSAS treated with CPAP), age = 46.7 ± 2.4, AHI = 63.5 ± 7.8; 15 patients (OSAS treated with oxygen), age = 47.1 ± 2.3, AHI = 58.6 ± 8.3 | Randomized placebo—controlled design | OSAS patients showed diffuse impairments,
particularly in terms of speed of information processing, attention and working memory, executive functioning, learning and memory, and alertness and sustained attention. |
|
| Yaouhi et al. 2009 [58] | 16 patients, age = 54.75 ± 5.71, AHI = 38.31 ± 14.33, 14 healthy controls | Case—control study | Patients showed poor performance on episodic memory. The remaining neuropsychological test scores (attention, vigilance, working memory, executive functions, and verbal fluency) were within the normal range. |
|
| Ferini-Strambi et al. 2003 [60] | 23 patients, age = 56.5 ± 6.13, AHI = 54.9 ± 13.37, 23 healthy controls. | Case—control study | OSAS patients had a significant impairment, compared to controls, in tests of sustained attention, visuospatial learning, executive function, motor performance, and constructional abilities. |
|
| Muñoz et al. 2000 [64] | 80 patients, age = 49.1, AHI = 60.2,
80 healthy controls | Clinical study of CPAP effects | Patients had a longer reaction time and poorer vigilance than healthy controls. |
|
| Engleman et al. 1994 [67] | 32 adult patients, AHI = 28 (range 7–129) | Placebo—controlled, crossover study | Patients showed improved vigilance, mental flexibility, and attention after CPAP treatment. |
|
| Engleman et al. 1999 [68] | 34 patients, age = 44,8 ± 6,
AHI = 10 ± 3 (range 5–15) | Placebo control
study of CPAP effects | Differences between before CPAP and after CPAP treatment in OSAS patients in attention (improvement in tests such as digit symbol examining attention skills). |
|
| Naegele et al. 1998 [69] | 17 patients, age = 44.80 ± 2.5, AHI = 53.5 7.6, 17 healthy controls | Case—control study of CPAP effects | Executive and learning disabilities as well as short-term memory impairment were found in OSAS patients. |
|
| Andreou and Agapitou 2007 [73] | 20 adolescents, age = 18.41 ± 0.37, AHI = 15.48 ± 7.08, 20 healthy controls | Clinical case—control study | Snoring adolescents showed reduced language and verbal abilities which were associated with disruption of sleep by apneas. |
|
| Aloia et al. 2004 [74] | 37 peer-reviewed articles were selected for this review | Review | Findings were equivocal for most cognitive domains. Treatment was noted to improve attention/vigilance in most studies but not constructional abilities or psychomotor functioning. |
|
| Rouleau et al. 2002 [75] | 28 patients, 18 healthy controls | Clinical study | OSAS patients did not show procedural skill learning deficits and episodic memory impairments. Frontal dysfunction, decrement in psychomotor efficiency, and vigilance characterized the impaired neuropsychological profile of OSAS patients. |
|
| Lau et al. 2010 [76] | 37 adult patients (moderate to severe OSAS treated with CPAP)
27 healthy controls | Clinical case—control study | Treated individuals performed at a comparable level to controls on basic working memory storage tests but showed a significant reduction on tests of working memory, requiring central executive functioning. The patients also performed worse on complex attention, executive function, and psychomotor speed tests than healthy controls. |
|
| Kingshott et al. 2000 [77] | 62 patients, age = 51 ± 11,
AHI 62 ± 33 | Clinical case study of CPAP treatment | Cognitive performance tests measuring coding speed, reaction time, and attention were found improved after CPAP therapy. |
|
| Mazza et al. 2005 [78] | 20 patients, age = 51 ± 2 yrs, AHI = 45 ± 22,
40 controls | Clinical case—control study | 95% of patients had vigilance and/or attention impairment. |
|
| Pierobon et al. 2008 [79] | 157 patients, age = 47.8 ± 11.9,
AHI = 54.4 ± 0.9 | Clinical case—normative study | Patients were impaired in short-term verbal memory and in short-term visual spatial memory. 40.8% did not have cognitive deficits. |
|
| Monasterio et al. 2001 [80] | 142 patients, age = 53 ± 9
AHI = 10–30 | Clinical case—control study | All the initial mean values of the cognitive tests performed were not impaired.
|
|
| Twigg et al. 2010 [81] | 60 patients, age = 51 ± 9,
AHI = 23.1, 60 healthy controls. | Clinical case—control study | Patients with OSAS displayed reduced performance on verbal episodic memory tasks, whereas visual episodic, semantic, and working memory remained intact. |
|
| Dècary et al. 2000 [82] | Review | Review | Poor general intellectual functioning, attention, memory and learning abilities, executive functions, and motor performance were found in OSAS patients. |
|
| Felver-Gant et al. 2007 [83] | 56 patients,
age = 52.8 ± 11.2, AHI = 41.4 ± 22.1 | Clinical case—control study | Working memory, declarative memory, executive functioning, and motor speed was impaired in OSAS patients. |
|
| Daurat et al. 2008 [84] | 28 patients,
29 healthy controls | Clinical case—control study | Recollection was strongly disturbed in patients, while attention was only slightly disturbed. |
|
| Aloia et al. 2003 [85] | 12 patients, age = 64.8 ± 6.4,
AHI = 51.2 ± 19.8 | Clinical case study | Attention, verbal delayed recall, constructional abilities, and language were impaired in OSAS patients. |
|
| Feuerstein et al. 1997 [86] | 10 patients,
10 healthy controls | Clinical case—control study of CPAP treatment | Patients were found with a significant decreased ability to initiate new mental processes and to inhibit automatic ones in conjunction with a tendency for perseverative errors. Deficits of verbal and visual learning abilities. |
|
| Lee et al. 2009 [87] | 30 patients,
30 healthy controls | Clinical case—control study | More severe cases of OSAS were associated with impaired language function reflecting frontal-subcortical pathology. |
|
| Grenèche et al. 2011 [88] | 12 patients, age = 51.8 ± 2.5, AHI = 58.9 ± 11.4, 10 healthy controls | Clinical case—control study | OSAS patients exhibited poor working memory performances. Immediate memory was not impaired. |
|
| Torelli et al. 2011 [89] | 16 patients, age = 55.8 ± 6.7,
AHI = 52.5 ± 26.0, 14 healthy controls | Clinical case—control study | Patients with OSAS had impaired auditory-verbal learning. No other significant differences between the two groups were detected. |
|
| Saunamäki et al. 2009 [90] | 40 patients, age = 47.2 ± 7.8, AHI = 41.0 ± 22.8; 20 healthy controls. | Clinical case—control study | Patients showed poorer performance than controls on executive functions. |
|
| Bardwell et al. 2001 [91] | 36 patients, Group A (placebo group), age = 48 ± 2.2, AHI = 43.6 ± 6.4, Group B (CPAP), age = 47 ± 1.9, AHI = 56.8 ± 5.4 | Clinical study of CPAP effects | OSAS patients exhibited poor executive functions. |
|
| Salorio et al. 2002 [92] | 28 patients, age: 28–60 yrs, 24 healthy controls | Clinical case—control study | Patients exhibited poorer recall abilities across learning trials, less efficient use of semantic clustering, and poorer use of semantic cues. Retention of previously encoded information and recognition was intact. No deficits in general executive control. |
|
| Lis et al. 2008 [93] | 20 patients, age = 53.4 ± 10.5, AHI = 57.9 ± 20.2; 10 healthy controls | Clinical case—control study | Deficits in tasks of executive functioning. |
|
| Beebe et al. 2003 [94] | 25 studies.
1092 patients,
899 healthy controls. | Meta-analytic review of research through 2001 | OSAS was found to have a negligible impact on intellectual and verbal functioning but a substantial impact upon vigilance and executive functioning. Data were mixed with regard to visual and motor functioning. Post-hoc inspection of the data suggested that tests of fine-motor coordination or drawing were more sensitive to OSAS than were tests of fine-motor speed or visual perception. Data were also mixed with regard to memory functioning. |
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