Abstract
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Objectives Both clinically and histopathologically patients with Dementia with Lewy Bodies (DLB) share many features with patients suffering from Parkinson’s or Alzheimer’s disease. Whereas Parkinson patients have severe deficits in their striatal dopamine transporter (DAT) binding, this is not the case for Alzheimer patients. Here, we studied cerebral DAT binding in early-stage DLB patients to assess if presence of core symptoms (parkinsonism, hallucinations, fluctuations) or cognitive symptoms were associated with DAT binding as measured with SPECT and [123I]-PE2I.
Methods 54 possible DLB patients were consecutively included in the study as they were referred to a diagnostic SPECT scan with [123I]-PE2I. On the day of the SPECT scan patients had a routine neurological examination including a Hoehn and Yahr (H&Y) score. In addition 3.6 ± 4.0 months pre or post SPECT scan they had an Addenbrooke’s cognitive examination (ACE). Patients were followed for an average of 16 months and 51 were given a final diagnosis of probable DLB based on current clinical guidelines.
Results The average BPND as a percentage of 28 normal age matched healthy controls was 43.2 ± 19.7 % in striatum; 48.1 ± 20.0 % in caudate nucleus and 38.3 ± 24.0 % in putamen. Presence of fluctuations or hallucinations did not predict striatal DAT binding (unpaired students t-test p>0.5 see figure), nor was there any correlation to H&Y score. Also, we did not find any correlation between subscores in the ACE test and DAT assessed by multiple regression analysis (multiple regression: p = 0.27; R2= 0.19).
Conclusions In the early stages of DLB most clinical symptoms do not seem to be driven primarily by striatal dopaminergic dysfunction