INFANTILE SPASMS - SEASONAL ONSET DIFFERENCES AND ZEITGEBERS

The health records of 76 infants with infantile spasms (IS) were revie wed retrospectively. The distribution of seizure onset was examined wi th respect to calendar month, annual changes in day length (photoperio d), and global solar radiation (GSR), IS onset was more frequent durin g the months with low GSR and short photoperiods. The greatest frequen cy of IS onset was in December and January (22 cases, 29%); the lowest was in April and May (8 cases, 10.5%). IS onset frequency (f) was mor e than twice as great in the months with a short photoperiod (10Light- 14Dark) and a low GSR (f = 11) as compared with months with a long pho toperiod (16Light-8Dark) and a high GSR (f = 5). IS onset frequency wa s 2.2-fold greater in months with a short photoperiod and a low GSR, T his finding suggests that environmental photoperiodic factors (zeitgeb ers) may play a role in the onset of IS. (C) 1997 by Elsevier Science Inc.