Sleep spindles in twins.
Sleep spindle characteristics and spindle power periodicity were studied in 4 identical and 3 fraternal twin pairs (mean age, 16 years). There were no significant genetic effects such as concordance between the identical twins and discordance between the fraternal twins for mean duration, mean amplitude and mean frequency of spindles. Spindle periodicity, which is correspondent to the sleep cycle, was visually more similar between the identical twins than between the fraternal twins. These observations suggest that the sleep cycle which is expressed by periodic appearance of spindle powers is genetically determined. On the other hand, some spindle characteristics and some physical measures had significant relationships. These relationships may suggest that some spindle characteristics are influenced by the individual development rather than by a genetic trait.
Hori
A
A
Department of Neurology, Kanazawa Medical University, Ishikawa, Japan.
Kazukawa
S
S
Endo
M
M
Kurachi
M
M
D000293:Adolescent; D001827:Body Height; D001835:Body Weight; D004569:Electroencephalography; D006801:Humans; D008297:Male; D012890:Sleep / Q000502:physiology*; D013909:Thorax / Q000254:growth & development; D014427:Twins