“…CSF activity of acetylcholine-esterase (AchE), the main enzyme involved in Ach degradation, has been reported to be similar in PD patients and controls (Jolkkonen et al, 1986; Ruberg et al, 1986; Zubenko et al, 1986; Sirviö et al, 1987; Yoshinaga et al, 1989; Manyam et al, 1990; Hartikainen et al, 1992), although there are studies which have described increased (Ruberg et al, 1986), decreased (Konings et al, 1995), or normal activity (Zubenko et al, 1986; Sirviö et al, 1987) in demented patients, and decreased activity only in those patients with the most severe disease (Hartikainen et al, 1992). …”