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[Disturbance of active sleep components in neonates with congenital hypothyroidism]
S Araki1, T Toyoura, J Kohyama
1Department of Pediatrics, Faculty of Medicine, Tokyo Medical and Dental University.
Insights
Congenital hypothyroidism impairs brainstem maturation, specifically affecting the tonic inhibitory system during REM sleep. Further research will explore long-term neurodevelopmental effects in affected children.
Area of Science:
- Neuroscience
- Developmental Biology
- Endocrinology
Context:
- Congenital hypothyroidism (CH) is a condition present at birth that can impact development.
- Early detection through neonatal screening allows for timely intervention.
- Brainstem maturation is crucial for various neurological functions, including sleep regulation.
Purpose:
- To investigate the impact of early-developmental hypothyroidism on functional brainstem maturation.
- To evaluate specific sleep indices related to muscle activity during REM sleep in infants with CH.
- To determine if thyroid hormone deficiency affects the maturation of tonic and phasic inhibitory systems in the brainstem.
Summary:
- Polysomnograms were analyzed in 7 infants with CH before treatment, comparing them to controls.
- The dissociation index (DI), reflecting tonic inhibition, was lower in CH patients.
- % body movements in REM bursts (% BM), reflecting phasic inhibition, was similar between groups.
- Findings suggest CH specifically affects the maturation of the tonic inhibitory system during REM sleep.
Impact:
- Thyroid hormone plays a critical role in functional brainstem maturation.
- Early hypothyroidism may have specific, lasting neurological consequences.
- Long-term neuropsychological follow-up is essential to fully understand the influence of CH on development.
Abstract:
In order to investigate the effect of hypothyroidism during the early development on the functional brainstem maturation, polysomnograms were recorded on 7 patients with congenital hypothyroidism detected by neonatal screening before treatment. The following two sleep indices for phasic muscle activity during rapid eye movement (REM) sleep were evaluated: dissociation index (DI) and % body movements in REMs burst (% BM). The DI is defined as the ratio of the number of twitch movements (TMs) during REM sleep to the sum of TMs and localized movements (LMs) during REM sleep. The % BM is the percentage of TMs and LMs which occur during bursts of REMs in relation to the sum of TMs and LMs during REM sleep. The DI and % BM can reflect maturation of the tonic and phasic inhibitory system functioning during REM sleep, respectively. In congenital hypothyroidism, DI was lower than that in controls, while % BM was identical. The tonic inhibitory system was specifically involved, whereas the phasic one was preserved. It is suggested that thyroid hormone could play an important role on the functional brainstem maturation. We propose to investigate their neuropsychological development over the long term to elucidate the influence of hypothyroidism.