The polysomnographic recordings of 24 normal subjects, 12 males and 12 females, ranging in age from 20 to 35 years (mean 27.8 ± 7.2), were examined.<h4 class="h4">Resultsh4>
A total of 1053 CAP sequences were counted with an average of 43.9 sequences per night. The mean duration of CAP sequences was 2 min and 33 s. Each CAP sequence was composed of an average of 5.6 CAP cycles. All subjects presented CAP sequences lasting at least 5 min and 30 s. The mean duration of CAP cycles was 26.9 ± 4.1 s. CAP cycles including subtypes A1 presented the highest correlation with the CAP sequence length (r = 0.92; p < 0.0001).<h4 class="h4">Conclusionsh4>
The progressive increase of CAP sequences length is linked to the progressive accumulation of CAP cycles.<h4 class="h4">Significanceh4>
CAP sequences can be considered as strings of time-constant modules, i.e., CAP cycles, which are involved in the dynamic tailoring of sleep structure.