Measuring the rate of progression of Parkinson's disease over a 5-year period with β-CIT SPECT

Recent imaging studies suggest a rapid degeneration of the dopaminergic system in early Parkinson's disease (PD), followed by a slowing of the degenerative process in advanced disease. In the present study, a group of early‐stage PD patients underwent three sequential [123I]β‐CIT SPECT studies to assess the decline of striatal dopamine transporter binding over a 5‐year period. Twenty‐one of a cohort of 24 early PD patients who participated in an earlier longitudinal β‐CIT SPECT imaging study [Mov Disord 2002;17:45–53] were included. Scan intervals were 26 ± 11 months (scan 1–2) and 38 ± 15 months (scan 2–3), respectively. The relative annual rate of decline of striatal β‐CIT binding from age‐expected normal values at the time of Scan 1 was used as primary outcome variable. The relative annual decline of striatal binding from Scan 1 to Scan 2 (4.5 ± 4.6%) and from Scan 2 to Scan 3 (3.0 ± 3.0%) was not significantly different. The non‐significant difference in progression rate was due mainly to the rapid early decline of striatal binding in 1 patient who subsequently developed a severe dysexecutive dementia syndrome. These data are not suggestive of substantial change in the course of dopaminergic degeneration in PD within the first 5 to 7 years after symptom onset. © 2003 Movement Disorder Society