Immediate and Long-term Neurocognitive Outcome in Patients with Obstructive Sleep Apnea Syndrome After Continuous Positive Airway Pressure Treatment

Neuropsychological and executive screening in obstructive sleep apnea: early effect of ventilatory therapy

BACKGROUND

Obstructive sleep apnea (OSA) is often associated with clinical, psychological and neuropsychological comorbidities such as Mild Cognitive Impairment (MCI). This study evaluated changes in clinical, psychosocial, Health Related Quality of Life (HRQoL) and neuropsychological profile in OSA subjects after ventilatory therapy, making comparison with normative data. The aim of the study was to verify the suitability of the HRQoL and neuropsychological screening tests in detecting variations in OSA subjects.

METHODS

At baseline, 32 OSA subjects underwent the following assessment: EuroQol (EQ-5D-3L) and EQ VAS, Hospital Anxiety and Depression Scale (HADS), Montreal Cognitive Assessment (MoCA) and Frontal Assessment Battery (FAB). After the ventilatory titration, 31 OSA subjects repeated the EQ VAS, MoCA and FAB assessment.

RESULTS

The analyzed subjects (77% male, 58.97±10.06 years old and 47.34±26.67 AHI [ev*hr^-1]) showed low emotive distress, a lower perception of HRQoL than normative data and 35.48% of them exhibited executive deficits, too. MCI was detected in 3.2% and 48.4% of subjects after normative Italian and international correction, respectively. Subsequently the ventilatory therapy and the rehabilitative interdisciplinary treatment, subjects improved in EQ VAS (68.23±18.73 vs. 87.13±10.80, P=0.0001), FAB scores (15,30±2.03 vs. 16,65±1,40, P=0.007) and MoCA memory subtest scores (2.16±1.34 vs. 3.06±1.63, P=0.008).

CONCLUSIONS

Ventilatory therapy provided during a rehabilitative and interdisciplinary program increased subjects' HRQoL, executive functions and verbal memory.

Reversible Verbal Memory Integration Deficits in Obstructive Sleep Apnoea

When presented with novel but semantically related elements after learning verbal material, healthy participants tend to endorse these items as previously learned. This reflects the normal integration and association of novel verbal information into long-term memory. How obstructive sleep apnoea (OSA) negatively impacts verbal memory performance, and whether deficits are reversible following positive airway pressure (PAP) treatment, remain elusive. We investigated immediate and delayed OSA- and PAP treatment-related effects on verbal memory integration, using a false memory paradigm. Twenty-three patients with OSA learned lists of words semantically related to target non-presented words (1) at baseline after a polysomnography diagnosis night, (2) after a consecutive polysomnography night under PAP titration, and (3) after three months of compliant PAP treatment. At each session, participants learned 10 different lists of words, each list comprising 15 semantically related items. They had then to recognize 15 minutes later (after an intermediate vigilance task) previously learned words within a list including studied words (learned), unstudied but semantically related items (lures), and non-related unstudied items (controls). Sleep quality and fatigue questionnaires, and psychomotor vigilance tests (PVT) were administered at each session. PAP treatment led to OSA remission and improvement in objective and subjective sleep quality. Crucially, recognition of learned and lure words increased after the first night under treatment and remained stable three months later, suggesting successful memory integration and restoration of semantic processes. No treatment-related outcome was found on PVT performance. OSA exerts a detrimental but PAP-reversible effect on verbal learning and semantic memory integration mechanisms underlying the acquisition of novel memory representations.

Three-dimensional photography for the evaluation of facial profiles in obstructive sleep apnoea

BACKGROUND AND OBJECTIVE

Craniofacial structure is an important determinant of obstructive sleep apnoea (OSA) syndrome risk. Three-dimensional stereo-photogrammetry (3dMD) is a novel technique which allows quantification of the craniofacial profile. This study compares the facial images of OSA patients captured by 3dMD to three-dimensional computed tomography (3-D CT) and two-dimensional (2-D) digital photogrammetry. Measurements were correlated with indices of OSA severity.

METHODS

Thirty-eight patients diagnosed with OSA were included, and digital photogrammetry, 3dMD and 3-D CT were performed. Distances, areas, angles and volumes from the images captured by three methods were analysed.

RESULTS

Almost all measurements captured by 3dMD showed strong agreement with 3-D CT measurements. Results from 2-D digital photogrammetry showed poor agreement with 3-D CT. Mandibular width, neck perimeter size and maxillary volume measurements correlated well with the severity of OSA using all three imaging methods. Mandibular length, facial width, binocular width, neck width, cranial base triangle area, cranial base area 1 and middle cranial fossa volume correlated well with OSA severity using 3dMD and 3-D CT, but not with 2-D digital photogrammetry.

CONCLUSION

3dMD provided accurate craniofacial measurements of OSA patients, which were highly concordant with those obtained by CT, while avoiding the radiation associated with CT.

Impact of Obstructive Sleep Apnea on Neurocognitive Function and Impact of Continuous Positive Air Pressure

There is evidence that obstructive sleep apnea (OSA) can negatively impact attention, memory, learning, executive function, and overall intellectual function in adults and children. Imaging techniques, including MRI, MR diffusion tensor imaging, MR spectroscopy, and fMRI, have provided additional insight into the anatomic and functional underpinnings of OSA-related cognitive impairment. Both animal and human studies have looked to elucidate the separate effects of oxygen desaturation and sleep fragmentation on independent aspects of cognition. Data from animal models point to neuro-inflammation and oxidative stress as driving factors of cognitive impairment.