epilepsy                package:HSAUR                R Documentation

_E_p_i_l_e_p_s_y _D_a_t_a

_D_e_s_c_r_i_p_t_i_o_n:

     A randomised clinical trial investigating the effect of an
     anti-epileptic drug.

_U_s_a_g_e:

     data("epilepsy")

_F_o_r_m_a_t:

     A data frame with 236 observations on the following 6 variables.

     '_t_r_e_a_t_m_e_n_t' the treatment group, a factor with levels 'placebo'
          and 'Progabide'.

     '_b_a_s_e' the number of seizures before the trial.

     '_a_g_e' the age of the patient.

     '_s_e_i_z_u_r_e._r_a_t_e' the number of seizures (response variable).

     '_p_e_r_i_o_d' treatment period, an ordered factor with levels '1' to
          '4'.

     '_s_u_b_j_e_c_t' the patient ID, a factor with levels '1' to '59'.

_D_e_t_a_i_l_s:

     In this clinical trial, 59 patients suffering from epilepsy were
     randomized to groups receiving either  the anti-epileptic drug
     Progabide or a placebo in addition to  standard chemotherapy. The
     numbers of seizures suffered in each  of four, two-week periods
     were recorded for each patient along  with a baseline seizure
     count for the 8 weeks prior to being  randomized to treatment and
     age. The main question of interest  is whether taking progabide
     reduced the number of epileptic seizures   compared with placebo.

_S_o_u_r_c_e:

     P. F. Thall and S. C. Vail (1990), Some covariance models for
     longitudinal count data with overdispersion. _Biometrics_, *46*,
     657-671.

_E_x_a_m_p_l_e_s:

       data("epilepsy", package = "HSAUR")
       library(lattice)
       dotplot(I(seizure.rate / base) ~ period | subject, data = epilepsy, 
               subset = treatment == "Progabide")
       dotplot(I(seizure.rate / base) ~ period | subject, data = epilepsy, 
               subset = treatment == "Progabide")

