Figure 17.

EMG of freezing of gait. From the top downward, EMG from, left (L) and right (R) paravertebral, gluteus maximus, hamstrings, quadricepts, pretibial, and triceps surae muscles. The lowest record shows a period of touching (on) or lifting up (off) from the floor of the plantar surface of the right big toe. On stepping, grouping of muscular contractions at rates of 4–6 Hz developed after initial normal steps, corresponding to trembling of the legs and freezing of steps. (From Yanagisawa, Ueno and Takami, 1991⁴⁶⁾).