Higher nigrostriatal dopamine neuron loss in early than late onset Parkinson's disease?--a [99mTc]-TRODAT-1 SPECT study.

Early-onset Parkinson's disease (EOPD) is distinct from the classic late-onset PD (LOPD) because of its slower disease progression. The aim of this study was to compare dopamine neuronal loss in EOPD with that of LOPD with the same disease duration, through dopamine transporter (DAT) estimation. Fourteen patients, seven EOPD (<50 years) and seven LOPD, matched for disease duration were scanned with [(99m)Tc]-TRODAT-1-SPECT (INER-Taiwan), and were assessed with standard PD scales. EOPD patients had 34% lower striatal DAT binding potential (BP) compared with that of LOPD patients (BP = 0.29 +/- 0.12, BP = 0.44 +/- 0.12, P < 0.02) with similar PD severity. These results suggest that EOPD patients have greater dopamine density loss than LOPD patients without motor-symptom worsening.