Resting state functional thalamic connectivity abnormalities in patients with post-stroke sleep apnoea: a pilot case-control study.

OBJECTIVE: Sleep apnoea is common after stroke, and has adverse effects on the clinical outcome of affected cases. Its pathophysiological mechanisms are only partially known. Increases in brain connectivity after stroke might influence networks involved in arousal modulation and breathing control. The aim of this study was to investigate the resting state functional MRI thalamic hyper-connectivity of stroke patients affected by sleep apnoea (SA) with respect to cases not affected, and to healthy controls (HC). PATIENTS AND METHODS: A series of stabilized strokes were submitted to 3T resting state functional MRI imaging and full polysomnography. The ventral-posterior-lateral thalamic nucleus was used as seed. RESULTS: At the between groups comparison analysis, in SA cases versus HC, the regions significantly hyper-connected with the seed were those encoding noxious threats (frontal eye field, somatosensory association, secondary visual cortices). Comparisons between SA cases versus those without SA revealed in the former group significantly increased connectivity with regions modulating the response to stimuli independently to their potentiality of threat (prefrontal, primary and somatosensory association, superolateral and medial-inferior temporal, associative and secondary occipital ones). Further significantly functionally hyper-connections were documented with regions involved also in the modulation of breathing during sleep (pons, midbrain, cerebellum, posterior cingulate cortices), and in the modulation of breathing response to chemical variations (anterior, posterior and para-hippocampal cingulate cortices). CONCLUSIONS: Our preliminary data support the presence of functional hyper connectivity in thalamic circuits modulating sensorial stimuli, in patients with post-stroke sleep apnoea, possibly influencing both their arousal ability and breathing modulation during sleep.

Post stroke sleep apnea hypopnea syndrome: a series of 12 consecutive stable stroke cases.

OBJECTIVES: Sleep Disordered Breathing (SDB) is a negative prognostic factor for stroke patients. In order to reveal: (1) the frequency of Sleep Apnea-Hypopnea Syndrome (SAHS) in the stable phase of the illness; (2) the type of SAHS, either obstructive (OSAHS) or central (CSAHS); (3) the possible association between SAHS and daily sleepiness, cardiac arrhythmias, stroke / TIA recurrence and location of the brain lesion, an observational study is on-going at Sapienza University of Rome. We report here the results of cases included in the feasibility study. PATIENTS AND METHODS: clinical evaluations, brain images and polisomnographic study were performed at discharge and after 4 and 9 months of stroke. RESULTS: Eleven out of the 12 patients included (91.6%) had an Apnea/Hypopnea Index-AHI >= 5. In 5 cases, the majority of total respiratory events were purely central in origin. In 3 of these 5 cases, a concomitant obstruction of the upper airways was revealed; the 2 remaining had risk factors for OSAHS (smoke, hypertension, BMI > 25). A significant association was found between central apnea/hypopnea events and cardiac arrhythmias (p value 0.017). CONCLUSIONS: These findings confirm the high prevalence of SDB, either obstructive or/and central, even in the stable phase of the illness, which in those patients who had accumulated risk factors for OSAHS result in Complex-sleep apnea/hypopnea syndrome (CompSAHS). As patients with CompSAHS are left with very disrupted breathing on continuous positive airway pressure, in order to select cases with stable stroke who benefit from continuos-positive airway pressure (C-PAP) treatment, further and more detailed clinical studies are needed to better distinguish CompSAHS from mixed SAHS.