Valeria Caldarelli

Longitudinal course of lung function and respiratory muscle strength in spinal muscular atrophy type 2 and 3

BACKGROUND Spinal muscular atrophy (SMA) is a common genetic disorder that causes severe hypotonia and weakness, and often fatal restrictive lung disease. The aim of the study was to describe the natural history of the respiratory involvement in patients with SMA type 2 and 3 in order to assess the relevance of the clinical classification and identify the parameters associated with the earliest and most rapid decline over time. METHODS Thirty-one patients aged 3-21 years were followed over a 10-year period. Lung function, blood gases, respiratory mechanics and muscle strength with recording of oesogastric pressures were measured during routine follow-up. RESULTS At least two measurements were available in 16 patients (seven type 2 and nine type 3). Among all the volitional and non-volitional, invasive and non-invasive tests, forced vital capacity (FVC) and sniff nasal inspiratory pressure (SNIP) were shown to be the most informative parameters, showing lower values in SMA type 2, with however a similar rate of decline in patients with SMA type 2 and 3. CONCLUSION Our results confirm an earlier decline in lung and respiratory muscle function in patients classified as SMA type 2 as compared with patients classified as type 3. This decline can be assessed by two simple non-invasive tests, FVC and SNIP, with the last maneuver being feasible and reliable in the youngest children, underlying its interest for the monitoring of children with SMA.

Sleep disordered breathing in patients with Prader–Willi syndrome: A multicenter study

Sleep disordered breathing (SDB) is common in patients with Prader–Willi syndrome (PWS) and systematic screening is recommended, especially before growth hormone treatment. The aim of the study was to describe the baseline SDB and therapeutic interventions in a large cohort of patients.

Non-invasive positive pressure ventilation in children

Non-invasive positive pressure ventilation is increasingly used in children both in acute and in chronic setting. Clinical data supporting safety, efficacy and limitations in children are growing. Technical problems related to the ventilators performance and interfaces selection have not been fully resolved, especially for younger children. Non-invasive ventilation can be applied at home. Its use at home requires appropriate diagnostic procedures, accurate titration of the ventilators, cooperative and educated families and careful, well-organized follow-up programs.

Polygraphic respiratory events during sleep in children treated with home continuous positive airway pressure: description and clinical consequences.

OBJECTIVE Data are scarce on respiratory events during sleep for children treated at home with continuous positive airway pressure (CPAP). The present study aimed to characterize the respiratory events with CPAP during sleep and to analyze their clinical consequences. PATIENTS/METHODS Consecutive polygraphies (PG) performed on stable children treated with CPAP were analyzed and scored using SomnoNIV Group definitions. For every respiratory event, the presence of a 3% oxygen desaturation and/or an autonomic arousal was systematically searched. Nocturnal gas exchange was assessed using summary data of oximetry and transcutaneous carbon dioxide pressure recordings. RESULTS Twenty-nine consecutive polygraphies, performed on 26 children (mean age 7.8 ± 6.2 years, mean CPAP use 10.6 ± 14.4 months), were analyzed. The index of total respiratory events was low (median value 1.4/h, range 0-34). The mean number of different types of respiratory events per PG was 2 ± 1 (range 0-4), with always a predominant event. Partial or total upper airway obstruction without a decrease in ventilatory drive was the most frequent event and was the most frequently associated with an oxygen desaturation (in 30% of the events) and an autonomic arousal (in 55% of the events). Weak correlations were observed between nocturnal oximetry and PG results. CONCLUSIONS The index of respiratory events during CPAP treatment for stable children is low. As these events may be associated with an oxygen desaturation or an autonomic arousal, and as nocturnal gas exchange cannot predict PG results, a systematic sleep study seems justified for the routine follow-up of children treated with CPAP.

Sleep architecture in infants with spinal muscular atrophy type 1.

OBJECTIVE Few reports on sleep patterns of patients with spinal muscular atrophy type 1 (SMA1) have been published and none on sleep microstructure. The aim of this study was to analyze sleep architecture and microstructure in a group of infants with SMA1, compared with age- and sex-matched controls. METHODS Twelve SMA1 patients (six males, mean age 5.9 months) and 10 controls (five males, mean age 4.8 months) underwent full polysomnography to evaluate their sleep architecture and microstructure by means of the cyclic alternating pattern (CAP). RESULTS Compared with control children, SMA1 patients showed increased sleep latency and apnea/hypopnea index. CAP analysis revealed a significant increase in the percentage of A1 CAP subtypes, a reduction of that of A3 subtypes and of A2 and A3 indexes (number/h), indicating a dysfunction of the arousal system in these patients. CONCLUSION The results indicate the presence of an abnormality of sleep microstructure in SMA1 patients, characterized by a reduction of A2 and A3 CAP subtypes. We hypothesize that SMA1 patients have reduced arousability during non-rapid eye movement sleep, which could be interpreted as additional evidence of central nervous system involvement in this disease.