SHATIN, Hong Kong, November 30 /PRNewswire/ -- Children that suffer from bedwetting, also known as Primary Nocturnal Enuresis (PNE), suffer from impaired brain function, sleep arousal disturbance and bladder dysfunction according to new results announced today by the International Children's Continence Society (ICCS) on the eve of World Children Bedwetting Day (1st December). With appropriate treatment however, these functions can be greatly improved. It is therefore concerning that almost half of parents ignore the problem in the hope it will go away.(1)

Over a nine year period, three studies involving 264 children from Hong Kong compared bedwetting (or 'enuretic') children and non-bedwetting (or 'non-enuretic') children to assess differences in sleep quality, central nervous system (CNS) functioning and cognitive performances.

Bedwetting is traditionally associated with deep sleep however new research indicates otherwise. In the first study,(2) sleep patterns of bedwetting children (35 children) were compared with non-bedwetters (21 age matched children). The children were monitored using overnight sleep polysomnography and continuous bladder monitoring.

Results suggest bedwetting children have inferior sleep quality compared to non-bedwetting children. Deep sleep occurred significantly less (p<0.05) and light sleep occurred more with bedwetting children (p<0.01). Bedwetting children are aroused by frequent bladder activities and so suffer disturbed and light sleep, sleep fragmentation and sleep deprivation. Paradoxically, they have an elevated awakening threshold making it more difficult for them to wake up. In addition, their night-time bladder capacity was markedly reduced to 44% of the expected capacity for their age.

The second study(3) investigated whether bedwetting children (52 children) suffered impairments in their CNS functioning when compared with non-bedwetting children (15 age matched children). Tests were conducted on the children's brainstem function, or prepulse inhibition of startle (PPI) reflex (a reflex reaction to a stronger stimulus - urge to urinate - is held back by a weaker stimulus - brain signalling the bladder not to empty). Results showed bedwetting children have significantly impaired brainstem functions as indicated by an impairment of PPI reflex (<0.005) when compared with non-bedwetting children.

Research using the widely recognised latency P300 event-related potentials (ERP) test, used to detect delays in cognition, showed that bedwetting children had longer delays in cognition and suffered more cognitive disturbances (<0.005).

Before treatment, the brainstem functions of bedwetting children are altered leading to impaired bladder function, sleep and awakening threshold. However after appropriate PNE treatment, they reached normalised results (PPI of startle p<0.05; latency of P300 ERPs p<0.05) when compared with non-bedwetting children.

The third study(4) investigated cognitive performance of bedwetting children (95 children) with that of non-bedwetting children (46 age matched children).

Using four key tests, the children were assessed on their intelligence score, focused and shifted attention, short-term and long-term memory, learning speed, speed of processing and reactions.

Bedwetting children performed worse in these tests than non-bedwetting children, demonstrating an overall impaired cognitive performance.

However six months of successful combination treatment comprising of desmopressin medication and urotherapy (aiming to correct the underlying bladder dysfunction) resulted in significant improvements with normalisation of sleep disturbance, brainstem functions and enhanced cognitive performance.

Specifically, bedwetting children showed improvements in:

- Sleep awakening ability (p<0.01)

- Brainstem functions as indicated by PPI reflex (p<0.05) and P300 ERP (p<0.05)

- Cognitive performance including intelligence score by Raven Progressive Matrices Test (p<0.05), short-term memory and acquisition ability by HK List Learning Test (p<0.005), focused attention by Digit Cancellation Test (p<0.005), and reaction by Conner's Continuous Performance Test (p<0.05)

Professor C K Yeung, President of the International Children's Continence Society (ICCS) and chief investigator of the above studies commented; "These studies have brought a breakthrough understanding of nocturnal enuresis and we now know that there is a bladder-brain dialogue in which bladder dysfunction can induce sleep disturbances, significant impairment of CNS functions and cognitive performance. More importantly, all the above parameters can be rectified and significantly improved upon correct diagnosis and successful treatment focused on the underlying bladder dysfunction. These will greatly enhance the well-being of enuretic children."

Bedwetting is the involuntary release of urine during sleep, occurring in children over the age of five and in the absence of any CNS defect.(5) Bedwetting is common and has similar prevalence rates worldwide. It is more common in boys than girls and if untreated, 16% of all seven year olds will still be affected.(6) In Europe, more than five million children suffer from bedwetting.(7) A misconception is that children will grow out of bedwetting but there is adult data to the contrary. Studies from Hong Kong indicate that 2.5% up to age 40 are still suffering from the disease, of which over 50% are having bedwetting three times or more every week.

Parents lack awareness and understanding of bedwetting despite it being a chronic medical condition. Almost half of parents ignore the problem,(1) whilst nearly a third delay action until the child is wetting the bed at least five times a week.(1) Furthermore, 80% mistakenly believe stress and worry are the major causes of child bedwetting.(1)

The reality is that bedwetting is a disease which can be treated effectively and permanently.

Notes to Editors

The International Children's Continence Society (ICCS)

The fundamental goal of the ICCS is to improve the quality of life and the life expectancy for all growing individuals with deficient bladder function, expressed as problems of storage and evacuation of urine. ICCS intends to approach this goal by increasing knowledge in all aspects of this problem area.


(1) BRMB International survey, 2002

(2) Yeung C K et al. Increased cortical arousal and light sleep in children with severe bedwetting: Evidences of a bladder-brain dialogue. To be published in New England Journal of Medicine (NEJM)

(3) Yeung C K. Bladder dysfunction, sleep disturbances and CNS function impairment in children with severe nocturnal enuresis: Evidences of a "bladder-brain dialogue". To be published.

(4) Yeung C K et al. Data presented at the ICCS course and International Enuresis Symposium, Hong Kong. November 30 - December 2, 2007. To be published.

(5) Nijman R M et al. Conservative management of urinary incontinence in childhood. In: Abram P et al. Incontinence. 2nd International Consultation on Incontinence. Health Publications Ltd, 2002; 515-551. Co-sponsored by WHO

(6) Alspac, Butler et al 2005, BJU; 96: 404-410


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