Polysomnographic features in infants with early diagnosis of congenital hypothyroidism.
Level 4 - case-series / case-control
Uncontrolled observational case series
PubMed 19665328 · doi:10.1016/j.braindev.2009.07.005
What was done
Infants aged 1.5 to 18 months diagnosed with congenital hypothyroidism through mass screening and started immediately on hormone replacement therapy were evaluated using morning polysomnography. Treatment duration before sleep recording ranged from 8 days to 17 months. Morning recordings lasted at least 2 hours, capturing more than one sleep cycle to assess sleep stages and respiratory events.
What was found
The studied group had a female-to-male ratio of 5:1. Central apnea occurred in 43% of infants (ranging from mild to severe) and hypopnea in 83%, primarily in infants around 4 and 8 months of age. The proportion displaying central apnea decreased with increasing age. Indeterminate (light) sleep increased and quiet (slow-wave) sleep decreased significantly regardless of age and treatment. REM sleep percentage correlated positively with age at treatment initiation and negatively with age at recording.
Why it matters
This study links early congenital hypothyroidism to central respiratory sleep abnormalities and altered sleep architecture, demonstrating that these respiratory events decrease as hormone replacement therapy and age advance.
Limits
The abstract does not state the total sample size (n) or exact statistical values (such as correlation coefficients or confidence intervals). There was no healthy control group, and sleep was measured only during brief daytime morning naps (at least 2 hours) rather than full overnight polysomnography.