Prepulse inhibition of startle, intelligence and familial primary nocturnal enuresis

Previous studies have shown a significant reduction of prepulse inhibition of startle in boys with primary nocturnal enuresis. Those enuretic boys who had higher IQs showed less prepulse inhibition. This study evaluates the association of prepulse inhibition and IQ in primary nocturnal enuresis in respect to family history of primary nocturnal enuresis. Prepulse inhibition of startle was studied in 83 boys with primary nocturnal enuresis and 57 non-enuretic boys using an interval of 120 ms between the onset of a 75 dB 1000 Hz tone and a 104 dB noise burst. Of the boys with primary nocturnal enuresis, 56 had a family history of primary nocturnal enuresis and 27 had no family history (no first-degree relative). Of the 57 non-enuretic boys, 42 also had no family history (no first-degree relative) of primary nocturnal enuresis, while 15 did have a positive family history. Associations between prepulse inhibition and IQ scores were compared among these four groups. Strong and significant associations between prepulse inhibition deficit and higher IQ scores in the enuretic group with familial primary nocturnal enuresis were unique in comparison to the other groups.

The strong heritabilities of primary nocturnal enuresis, intelligence and prepulse inhibition suggest genetic mediation of the association of prepulse inhibition with intelligence in familial primary nocturnal enuresis.