The role of the amygdala in ictal central apnea: insights from brain MRI morphometry.

OBJECTIVE: Ictal central apnea (ICA) is a frequent correlate of focal seizures, particularly in temporal lobe epilepsy (TLE), and regarded as a potential electroclinical biomarker of sudden unexpected death in epilepsy (SUDEP). Aims of this study are to investigate morphometric changes of subcortical structures in ICA patients and to find neuroimaging biomarkers of ICA in patients with focal epilepsy. METHODS: We prospectively recruited focal epilepsy patients with recorded seizures during a video-EEG long-term monitoring with cardiorespiratory polygraphic recordings from April 2020 to September 2022. Participants were accordingly subdivided into two groups: patients with focal seizures with ICA (ICA) and without (noICA). A pool of 30 controls matched by age and sex was collected. All the participants underwent MRI scans with volumetric high-resolution T1-weighted images. Post-processing analyses included a whole-brain VBM analysis and segmentation algorithms performed with FreeSurfer. RESULTS: Forty-six patients were recruited (aged 15-60 years): 16 ICA and 30 noICA. The whole-brain VBM analysis showed an increased gray matter volume of the amygdala ipsilateral to the epileptogenic zone (EZ) in the ICA group compared to the noICA patients. Amygdala sub-segmentation analysis revealed an increased volume of the whole amygdala, ipsilateral to the EZ compared to controls [F(1, 76) = 5.383, pFDR = 0.042] and to noICA patients ([F(1, 76) = 5.383, pFDR = 0.038], specifically of the basolateral complex (respectively F(1, 76) = 6.160, pFDR = 0.037; F(1, 76) = 5.121, pFDR = 0.034). INTERPRETATION: Our findings, while confirming the key role of the amygdala in participating in ictal respiratory modifications, suggest that structural modifications of the amygdala and its subnuclei may be valuable morphological biomarkers of ICA.

Altered amygdala volumes and microstructure in focal epilepsy patients with tonic-clonic seizures, ictal, and post-convulsive central apnea.

OBJECTIVES: Sudden unexpected death in epilepsy (SUDEP) is a leading cause of death for patients with epilepsy; however, the pathophysiology remains unclear. Focal-to-bilateral tonic-clonic seizures (FBTCS) are a major risk factor, and centrally-mediated respiratory depression may increase the risk further. Here, we determined the volume and microstructure of the amygdala, a key structure that can trigger apnea in people with focal epilepsy, stratified by the presence or absence of FBTCS, ictal central apnea (ICA), and post-convulsive central apnea (PCCA). METHODS: Seventy-three patients with focal impaired awareness seizures without FBTC seizures (FBTCneg group) and 30 with FBTCS (FBTCpos group) recorded during video electroencephalography (VEEG) with respiratory monitoring were recruited prospectively during presurgical investigations. We acquired high-resolution T1-weighted anatomic and multi-shell diffusion images, and computed neurite orientation dispersion and density imaging (NODDI) metrics in all patients with epilepsy and 69 healthy controls. Amygdala volumetric and microstructure alterations were compared between three groups: healthy subjects, FBTCneg and FBTCpos groups. The FBTCpos group was further subdivided by the presence of ICA and PCCA, verified by VEEG. RESULTS: Bilateral amygdala volumes were significantly increased in the FBTCpos cohort compared to healthy controls and the FBTCneg group. Patients with recorded PCCA had the highest increase in bilateral amygdala volume of the FBTCpos cohort. Amygdala neurite density index (NDI) values were decreased significantly in both the FBTCneg and FBTCpos groups relative to healthy controls, with values in the FBTCpos group being the lowest of the two. The presence of PCCA was associated with significantly lower NDI values vs the non-apnea FBTCpos group (p = 0.004). SIGNIFICANCE: Individuals with FBTCpos and PCCA show significantly increased amygdala volumes and disrupted architecture bilaterally, with greater changes on the left side. The structural alterations reflected by NODDI and volume differences may be associated with inappropriate cardiorespiratory patterns mediated by the amygdala, particularly after FBTCS. Determination of amygdala volumetric and architectural changes may assist identification of individuals at risk.

Polysomnographic predictors of abnormal brainstem imaging in children.

STUDY OBJECTIVES: Evaluation of elevated central apnea-hypopnea index (CAHI) or prolonged central apneas in pediatric patients typically includes neuroimaging with a focus on brainstem pathology. There is little evidence guiding thresholds of polysomnographic variables that accurately predict abnormal neuroimaging. We sought to evaluate whether additional polysomnographic variables may help predict brainstem pathology. METHODS: A 10-year retrospective review of patients ages 1-18 years who received a brain magnetic resonance imaging (MRI) for an indication of central sleep apnea diagnosed via polysomnography was performed. Demographics, medical history, polysomnogram variables, and MRI results were compared. RESULTS: This study included 65 patients (69.2% male). The median age was 5.8 years (interquartile range, 3.0-8.3). Most patients had negative (normal or nonsignificant) MRIs (n = 45, 69.2%); 20 (30.8%) had abnormal MRIs. Of the patients with abnormal MRIs, 13 (20.0%) had abnormalities unrelated to the brainstem. Seven patients (10.8%) were found to have brainstem pathology and had a median CAHI of 10.8 events/h (interquartile range, 6.5-21.9), and three of seven (42.9%) had hypoventilation and were more likely to have developmental delay, abnormal neurological examinations, and reflux. Other patients (n = 58) had a median CAHI of 5.6 events/h (interquartile range, 3.1-9.1), and seven (12.1%) had hypoventilation. Area under the curve and receiver operating characteristic curves showed a CAHI ≥ 9.5 events/h and ≥ 6.4% of total sleep time with end-tidal CO2 ≥ 50 mm Hg predicted abnormal brainstem imaging. Prolonged central apneas did not predict abnormal brainstem imaging. CONCLUSIONS: Most patients with central sleep apnea do not have MRIs implicating structurally abnormal brainstems. Utilizing a cutoff of CAHI of ≥ 9.5 events/h, ≥ 6.4% total sleep time with end-tidal CO2 ≥ 50 mm Hg and/or frank hypoventilation, and additional clinical history may optimize MRI utilization in patients with central sleep apnea.

Adult-onset congenital central hypoventilation syndrome due to PHOX2B mutation.

Central hypoventilation in adult patients is a rare life-threatening condition characterised by the loss of automatic breathing, more pronounced during sleep. In most cases, it is secondary to a brainstem lesion or to a primary pulmonary, cardiac or neuromuscular disease. More rarely, it can be a manifestation of congenital central hypoventilation syndrome (CCHS). We here describe a 25-year-old woman with severe central hypoventilation triggered by analgesics. Genetic analysis confirmed the diagnosis of adult-onset CCHS caused by a heterozygous de novo poly-alanine repeat expansion of the PHOX2B gene. She was treated with nocturnal non-invasive ventilation. We reviewed the literature and found 21 genetically confirmed adult-onset CCHS cases. Because of the risk of deleterious respiratory complications, adult-onset CCHS is an important differential diagnosis in patients with central hypoventilation.

Upper Airway Narrowing during Central Apnea in Obese Adolescents.

RATIONALE: The use of real-time magnetic resonance imaging (MRI) for the evaluation during sleep-related respiratory events can lead to better understanding of airway dynamics. OBJECTIVES: To investigate the dynamic anatomy of the upper airway during central apnea. METHODS: The study included obese adolescents who snore and were otherwise healthy. Subjects underwent an overnight baseline polysomnogram. Subjects slept during a 24-minute real-time upper airway MRI scan wearing a full face mask attached to a pneumotach. Sleep versus wakefulness during the MRI was inferred from the heart rate and respiratory patterns. Central apneas were scored using tracings of facemask airflow and abdominal bellows. The cross-sectional area of the upper airway before, during, and after each central apnea event was recorded. RESULTS: Eight subjects were studied and 57 central apnea events were observed during real-time MRI scanning during natural sleep. The median age of subjects was 14.0 years (interquartile range [IQR], 13.5 to 15.5). The median average reduction in cross-sectional area during central apnea events was -38% (IQR, -27 to -51) for primary snorers and -45% (IQR, -40 to -54) for subjects with obstructive sleep apnea. The percentage decrease in cross-sectional area of upper airway during a central apnea event was positively correlated to the length of the central apnea (ρ = 0.389; r2 = 0.152; P = 0.003). CONCLUSIONS: We observed that there is upper airway narrowing during central apneas during natural sleep in obese adolescent subjects, using real-time MRI.

Neuropsychological profile and social cognition in congenital central hypoventilation syndrome (CCHS): Correlation with neuroimaging in a clinical case.

INTRODUCTION: Congenital central hypoventilation syndrome (CCHS) is a rare genetic disorder due to paired-like homeobox gene (PHOX2B) mutations. CCHS patients suffer from dysregulation of the autonomic nervous system characterized by the absence of or extremely reduced response to hypercapnia and hypoxia, with neuropsychological deficits. The aim of this exploratory study is to describe the longitudinal neuropsychological profile and its correlations with magnetic resonance imaging (MRI) of a child with CCHS with a PHOX2B mutation. METHOD: A comprehensive neuropsychological evaluation was conducted serially at age 7 years 4 months and 10 years 3 months, including assessment of intellectual functioning (IQ), motor functioning, perception, attention, executive functions, language, memory, social cognition, academic skills, and psychopathology. Reliable change index (RCI) scores were used to assess changes between assessments. We collected spin lattice relaxation time (T1)-weighted, fluid-attenuated inversion recovery (FLAIR), and spin spin lattice relaxation time (T2)-weighted images from the child at age 10 years 3 months using a 1.5-tesla MRI scanner. RESULTS: IQ, processing speed index (PSI), social cognition (theory of mind and facial emotion recognition), selective attention, naming, academic skills (reading/comprehension), and manual speed with right hand declined in the second evaluation relative to the initial evaluation, while visuoconstructional praxis, receptive vocabulary, working memory, and arithmetic skill improved. The patient showed a remarkable global deterioration in executive functions (planning, task flexibility, behavioral regulation, and metacognition) as revealed by parental report and clinical evaluation. MRI revealed gliosis from the head to tail of the hippocampus and thinning of parahippocampal gyri. CONCLUSIONS: In a clinical case of CCHS, serial evaluation revealed deterioration of executive functions and social cognition over a 3-year interval. These changes corresponded to hippocampal damage as revealed in MRI, which may have affected social cognition through its role in the default mode network. Serial neuropsychological assessment is clinically useful in managing the needs of these patients.

Microstructural cerebral lesions are associated with the severity of central sleep apnea with Cheyne-Stokes-respiration in heart failure and are modified by PAP-therapy.

This study investigated the association of microstructural cerebral lesions with central sleep apnea with Cheyne-Stokes-respiration (CSA-CSR) in heart failure (HF) patients and the effect of positive airway pressure therapy (PAP) of CSA-CSR on these lesions. PAP-therapy was initiated in patients with HF with midrange and with reduced ejection fraction (NYHA≥II; left ventricular ejection fraction <50%) and proven CSA-CSR. Cerebral magnetic resonance imaging (MRI) scans at 3T including diffusion tensor imaging were obtained before and after 4 months of PAP-therapy. Cerebral MRI scans revealed microstructural lesions in all 11 patients with HF with midrange or reduced ejection fraction and CSA-CSR (64±8years, 82% male, left ventricular ejection fraction 37±11%) that were focussed on the brainstem and frontal cerebral regions. This microstructural damage correlated with the severity of CSA-CSR and 4 months of PAP-therapy lead to voxel clusters of altered fiber integrity in these lesions. Microstructural cerebral lesions might contribute to the pathophysiology of CSA-CSR in HF. In these patients PAP-therapy induces neuronal plasticity.

Low leptin concentration may identify heart failure patients with central sleep apnea.

Low leptin concentration has been shown to be associated with central sleep apnea in heart failure patients. We hypothesized that low leptin concentration predicts central sleep apnea. Consecutive ambulatory New York Heart Association (NYHA) classes I-IV heart failure patients were studied prospectively, including measurement of serum leptin, echocardiography and polysomnography. Sleep apnea was defined by type (central/mixed/obstructive) and by apnea-hypopnea index ≥5 by polysomnography. Subjects were divided into four groups by polysomnography: (1) central sleep apnea, (2) mixed apnea, (3) no apnea and (4) obstructive sleep apnea. Fifty-six subjects were included. Eighteen subjects were diagnosed with central sleep apnea, 15 with mixed apnea, 12 with obstructive apnea and 11 with no sleep apnea. Leptin concentration was significantly lower in central sleep apnea compared to obstructive apnea (8 ± 10.7 ng mL-1 versus 19.7 ± 14.7 ng mL-1 , P Ë‚ 0.01) or no sleep apnea (8 ± 10.7 ng mL-1 versus 17.1 ± 8.4 ng mL-1 , P Ë‚ 0.01). Logistic regression showed leptin to be associated independently with central sleep apnea [odds ratio (OR): 0.19; 95% confidence interval (CI): 0.06-0.62; area under the curve (AUC): 0.80, P < 0.01]. For the detection of central sleep apnea, a cut-off value for leptin concentration 5 ng mL-1 yielded a sensitivity of 50% and specificity of 89%. In conclusion, a low leptin concentration may have utility for the screening of heart failure patients for central sleep apnea.

A 58-Year-Old Man With Position-Dependent Nocturnal Dyspnea.

CASE PRESENTATION: A 58-year-old man with idiopathic pulmonary fibrosis, who had received a right-sided single-lung transplant 2 years earlier, was referred to the sleep clinic for the assessment of nocturnal position-dependent episodes of dyspnea and frequent arousals when lying on his right side. There was no subjective worsening of daytime respiratory symptoms, but he complained of fatigue and unrefreshing sleep. His Epworth Sleepiness Scale score was 12/24. After lung transplantation he had a favorable course while receiving immunosuppression with prednisolone, everolimus, and mycophenolate mofetil. In addition, he had received diagnoses of stable coronary artery disease and moderate chronic kidney failure.

The reduction of central sleep apnoea severity in the left lateral position is not due to an improvement in cardiac haemodynamics in patients with chronic heart failure.

OBJECTIVE: The severity of central sleep apnoea (CSA), a common comorbidity in patients with chronic heart failure (CHF) and reduced ejection fraction, markedly decreases from the supine to the lateral sleeping position, with no difference between the left and right positions. The mechanisms responsible for this beneficial effect have not yet been elucidated. METHODS: We tested the hypothesis that CSA attenuation in the left lateral position is due, at least in part, to an improvement in cardiac haemodynamics. Sixteen CHF patients (male, aged 60 ± 7 years, New York Heart Association class 2.6 ± 0.5, left ventricular ejection fraction [LVEF] 30% ± 5%) with moderate-to-severe CSA underwent two consecutive tissue Doppler echocardiography examinations in random order, one in the left lateral position (90°) and the other in the supine position (0°). The following parameters were obtained: left ventricular end-diastolic volume (LVEDV) and LVEF, left atrial volume (LAV) and right atrial volume (RAV), mitral regurgitation (MR), cardiac output (CO), transmitral protodiastolic (E) wave deceleration time (DT), E/e' ratio, tricuspid annular plane systolic excursion (TAPSE), and right ventricular-atrial gradient (RVAG). RESULTS: The LAV, MR, E/e', RAV, and RVAG significantly increased, whereas the LVEF and TAPSE significantly decreased in the left lateral position. All changes, however, were of negligible clinical significance. No significant changes were observed in CO, DT, and LVEDV. CONCLUSIONS: This study shows that the reduction of CSA severity from the supine to the left lateral position in patients with CHF is not due to an improvement in cardiac haemodynamics. Other, noncardiac factors are likely to represent the main cause.

Evaluation of the central sleep apnea in asymptomatic children with Chiari 1 malformation: an open question.

INTRODUCTION: Type I is the most common Chiari malformation in children. In this condition, the lower part of the cerebellum, but not the brain stem, extends into the foramen magnum at the base of the skull leading to intermittent brain hypertension. In symptomatic children, central sleep apneas are shown in polysomnography evaluation. A central apnea index of 1/h or more is considered abnormal, but >5/h is clearly considered pathological. Therefore, central sleep apnea evaluation in pediatric age may show great age-related variability. METHOD AND SUBJECTS: We present three patients who were assessed by polysomnography with two different scores for central sleep apneas published in the literature: the method by Scholle (2011) and the American Academy of Sleep Medicine scoring system (2012). CONCLUSIONS: We speculated that the Scholle scoring system can be more helpful in assessing children with asymptomatic Chiari 1 malformation for a closer follow-up. More studies are needed.

Central sleep apnea in children: experience at a single center.

OBJECTIVE: Central sleep apnea (CSA) syndromes are rare in children and data in children over one year of age are scarce. The aim of the study was to describe the sleep characteristics, underlying disorders, management, and outcome of children with CSA. PATIENTS/METHODS: A retrospective chart review of all children >1 year of age, diagnosed with CSA on a laboratory sleep study during a 20-month period, was performed. CSA was defined by a central apnea index (CAI) >5 events/h. The clinical management and the patient's outcome were analyzed. RESULTS: Eighteen of 441 (4.1%) patients recorded during the study period had CSA. The median CAI, pulse oximetry, and oxygen desaturation index were 13/h (range 6-146), 96% (93-98%), and 18/h (6-98), respectively. Neurosurgical pathologies represented the most common underlying disorders with Arnold-Chiari malformation in four and ganglioglioma in three patients. Other underlying disorders were Prader-Willi syndrome (N = 3), achondroplasia (N = 2), and Down syndrome, with one patient having an achondroplasia and a Down syndrome. The remaining six patients had other genetic diseases. The most common investigation was brain magnetic resonance imaging (MRI). Individualized management with neurosurgery and/or chemotherapy, continuous positive airway pressure (in two patients having associated obstructive events), or noninvasive ventilation resulted in an improvement in CSA and the clinical presentation in 11 patients. CONCLUSION: CSA is rare in children >1 year of age. Underlying disorders are dominated by neurosurgical disorders. Individualized management is able to improve CSA and the clinical condition in most patients.

Association of Central Sleep Apnea with Impaired Heart Structure and Cardiovascular Hemodynamics in Patients with Chronic Heart Failure.

BACKGROUND Advanced heart failure (HF) is commonly accompanied by central sleep apnea (CSA) with Cheyne-Stokes respiration (CSR). The aim of this study was to evaluate the relationship between CSA/CSR and other clinical features of HF, with particular emphasis on cardiovascular hemodynamics. MATERIAL AND METHODS In 161 stable HF patients with left ventricular ejection fraction (LVEF) ≤45% (NYHA class I-III; mean LVEF 32.8%) the clinical evaluation included: LVEF; left and right ventricular end-diastolic diameter (LVDd, RVDd); ratio of early transmitral flow velocity to early diastolic septal mitral annulus velocity (E/e') assessed by echocardiography; stroke index (SI); heart rate (HR); cardiac index (CI); and systemic vascular resistance index (SVRI) assessed by impedance cardiography (ICG). The comparison was performed between 2 subgroups: one with moderate/severe CSA/CSR - CSR_ [+] (n=51), and one with mild or no CSA/CSR - CSR_ [-] (n=110). RESULTS CSR_ [+] patients presented more advanced NYHA class (p<0.001) and more frequently had permanent atrial fibrillation (p=0.018). Moreover, they had: lower LVEF (p<0.0001); higher LVDd (p<0.0001), RVDd (p<0.001), and E/e' (p<0.001); lower SI (p<0.001) and CI (p=0.009); and higher HR (p=0.044) and SVRI (p=0.016). The following predictors of CSR_ [+] were identified: NYHA class (OR=3.34 per class, p<0.001, which was the only independent predictor); atrial fibrillation (OR=2.29, p=0.019); RV enlargement (OR=2.75, p=0.005); LVEF<35% (OR=3.38, p=0.001); E/e' (OR=3.15; p=0.003); and SI<35 ml/m2 (OR=2.96, p=0.003). CONCLUSIONS Presence of CSA/CSR in HF is associated with NYHA class, atrial fibrillation and more advanced impairment of cardiovascular structure and hemodynamics. Patient functional state remains the main determinant of CSR.

CLINICAL CASE OF THE INNATE CENTRAL HYPOVENTILATION SYNDROME IN THE PARTURIENT.

The syndrome "of the curse of Undina" or the innate central hypoventilation syndrome with the second disorder of cen- tral nervous system is the result of the disrupted vegetative control of the respiration in the absence of neuromuscular diseases and disturbances of the mechanics of respiration. In the clinical practice diagnostics of this state is complex, frequently the cases remain not diagnosed. Taking into account clinical manifestations and depending on the degree of their intensity, early diagnostics, which warns the undesirable consequences ofthe episodes ofhypoxia and hypercapnia, that ensures the proper checking of the episodes of asphyxia, determines not only the forecast of disease, but also life of patient. The purpose ofthis work is the idea of the clinical case of this rarely meeting illness.

Efficacy of tracheostomy for central alveolar hypoventilation syndrome caused by lateral medullary infarction.

Central alveolar hypoventilation syndrome (CAHS) is a rare and potentially fatal condition. However, respiratory care for patients with CAHS caused by lateral medullary infarction (CAHS-LMI) remains an important unsolved problem. We describe 2 patients with CAHS-LMI and review the case reports for 17 previously described patients. Patient 1 was a 78-year-old man who was referred to our hospital because of dizziness. After admission, Wallenberg syndrome developed. Magnetic resonance imaging showed left LMI. He had hypercapnia and respiratory acidosis the next afternoon and temporarily received mechanical ventilation. A tracheotomy was performed on the 12th hospital day, and the patient was weaned from the ventilator on the 18th hospital day. Patient 2 was 72-year-old man who was referred to our hospital because of dizziness and gait disturbance. Wallenberg syndrome was diagnosed after admission, and magnetic resonance imaging showed right LMI. His consciousness deteriorated, and hypercapnia developed on the ninth hospital day. The patient received ventilatory support, and a tracheotomy was performed on the 12th hospital day. He was weaned from the ventilator by the 16th hospital day. Consistent with our findings, most previously reported cases of CAHS-LMI were initially associated with mild symptoms, which subsequently worsened. Five of the 19 patients (26.3%) died within 1 month after onset, and 7 patients (36.8%) died within 1 year. Tracheotomy was performed in 12 patients, 2 of whom died 1 month after onset (16.7%); another patient died of chronic renal failure after 2 years. Tracheotomy seemed to be an effective procedure in patients with CAHS-LMI. We speculate that tracheotomy assists alveolar ventilation by reducing dead space ventilation. Closure of the tracheotomy should, therefore, be avoided in patients with CAHS-LMI, even if respiratory status is good.

Progressive paranoid psychosis in a 20-year-old with central congenital hypoventilation syndrome.

A 20-year-old man with a history of congenital central hypoventilation syndrome presented with recent-onset psychosis, catatonia, and a diagnosis of schizophrenia. Psychiatric symptoms were resistant to conventional treatment. A fluorodeoxyglucose positron emission tomography scan of the brain obtained during the hospitalization revealed a hypometabolism distribution more consistent with hypoperfusion than with primary central nervous system disease. Increased mechanical ventilation was successfully used to treat the psychiatric symptoms.