Inconsistency between severe substantia nigra degeneration with Lewy bodies and clinical parkinsonism in dementia patients: a cliniconeuropathological study

In a retrospective cliniconeuropathological study, we reviewed all the case s received in our dementia brain bank during a 4-year period to determine i f all patients with severe substantia nigra (SN) degeneration and SN Lewy b odies (LBs) exhibited prominent signs of parkinsonism and were treated for parkinsonism during the disease course. The SN of 426 cases were graded for microscopic degeneration using a semiquantitative five-tiered scale, with grade 0 indicating normal and grade 4 the most severe degeneration. Twenty- nine cases with grade 3 (16) or grade 4 (13) SN degeneration with SN LBs an d clinical records were identified. Ten had been treated for parkinsonism ( 6 grade 3, 4 grade 4) and 19 had not. Whereas most of the patients had exhi bited signs of end-stage parkinsonism during their last year, 1 grade 3 and 2 grade 4 patients apparently never exhibited prominent signs of parkinson ism during the course of their dementia. No clear neuropathological differe nces were noted between these patients that did not have prominent signs an d a control group of six patients with clinical Parkinson's disease with de mentia (parkinsonism onset at least 1 year before dementia onset). We concl ude that in patients with dementia there is an inconsistent relationship be tween the expression of clinical parkinsonism during life and severe SN deg eneration with LBs identified at necropsy.