Freezing of gait (FOG) is characterized by difficulty in initiating or maintaining locomotion, frequently associated with falls in advanced disease, often related to the OFF state, and may be responsive or unresponsive to dopaminergic therapy. The role of dopamine depletion is still debated in the pathogenesis of FOG and Falls.
We aimed to evaluate the role of I123-FP-CIT-SPECT imaging in predicting FOG and falls in a cohort of PD de-novo patients followed up for five years.
Ninety-four PD de-novo patients underwent 123I-FP-CIT SPECT at baseline. Basal ganglia matching tool was used to obtain semiquantitative measures of caudate and putamen uptake. Each patient was assessed with Unified Parkinson’s Disease Rating Scale (UPDRS) part II and III and Mini Mental State Examination (MMSE) at baseline and each year in the follow up. FOG and falls were assessed through UPDRS III. We compared baseline clinical, demographic, and SPECT indices between patients who developed FOG and falls and subjects who did not.
During follow-up, 47% patients developed FOG, 15% falls. No significant statistical differences in UPDRS III and MMSE at baseline were found between patients with FOG and Falls and those without these features. Patients with FOG had a decreased uptake at baseline in caudate (right 2,77 vs. 3,32; p<0,005; left 3,38 vs. 3,02; p<0,06) and in putamen (right 1,42 vs. 1,86; p <0,002, left 1,67 vs. 1,97; p<0,06). No significant differences in baseline striatal uptake were observed in relationship with the risk of falls.
A baseline lower uptake value of striatum seems to be predictor of FOG and this evidence might support, a link between FOG and dopamine depletion both in caudate and putamen, at least in the early stage of disease. Risk of Falls, although often associated with FOG in PD, doesn’t relate to dopaminergic dysfunction, supporting the hypothesis of its complex multifactorial genesis.