My completely speculative hypothesis is that the phenomenon is related to balance, as a long head would tend to rotate around the neck much easier than a short one, due to the greater torque that develops in an oblong object (in the supine position). Our heads do not normally wobble left and right because of our neck muscles, and the added effort needed to maintain a longer head in supine position may cause discomfort/strain during sleep, and hence enuresis.
Sleep Breath. 2010 Jul 6. [Epub ahead of print]
Facial patterns and primary nocturnal enuresis in children.
Carotenuto M, Esposito M, Pascotto A.
PURPOSE: Aims of our study are evaluating: (1) the prevalence of dolicofacial pattern among enuretic and control-group children, (2) the prevalence of an abnormal head posture in bedwetters, and (3) the correlation with sleep-related breathing disorders (SRBD) identified by polysomnography (PSG) recording. Nocturnal enuresis is a multifactorial disease, but has been related also to obstructive sleep-disordered breathing in both adults and children. Anatomical factors recognized to predispose to SRBD include adenotonsillar hypertrophy, neuromuscular disorders, craniofacial abnormalities associated with macroglossia, retrognathia or maxillary hypoplasia, and obesity. METHODS: Two hundred seventy enuretic children aged 7-12 years (mean 9.62 +/- 2.31) were compared with a control-matched group of 274 children. To screen nocturnal sleep habits, all subjects' mothers filled out the Sleep Disturbance Scale for Children. Among these scales, only SBD scale was taken into account. Sleep breathing disorders (SBD) scale is composed of three items: sleep breathing difficulties, sleep apnea, and snoring. Cephalic index was calculated for each patient in order to identify facial patterns. An overnight PSG was performed in 28 (15 males, 13 females), randomly chosen, enuretic children and in 38 healthy volunteer controls (18 males, 20 females) matched for age (8.73 +/- 0.79 vs. 9.12 +/- 1.23; p = 0.147) and sex distribution (chi-square = 0.062; p = 0.803). RESULTS: Bedwetters show different sleep habits, higher prevalence of dolicofacial pattern, and abnormal head posture more than controls. CONCLUSIONS: Our preliminary study support further investigation of usage of the cephalic index as a predictor of SRBD.