It's an exceptionally fast, shallow, tubular and heavy wave.

这是一个异常快速、浅、管状和沉重的波浪。

Your brain waves slow down a bit too, with the alpha rhythm of rather fast waves predominating for the first few minutes.This is called stage 1 sleep.

除了开始几分钟比较快的α节奏外，脑电波也稍有减缓。这被称为第一阶段睡眠。