Longitudinal follow-up of SWEDD subjects in the PRECEPT Study.
OBJECTIVE
To compare the clinical and imaging characteristics of those PRECEPT (Parkinson Research Examination of CEP-1347 Trial) subjects with a scan without evidence of dopaminergic deficit (SWEDD) to those with dopamine transporter (DAT) deficit scans at study baseline and during a 22-month follow-up.


METHODS
Baseline (n = 799) and 22-month follow-up (n = 701) [(123)I] β-CIT SPECT scans were acquired. The percent change in [(123)I] β-CIT striatal binding ratio, the percentage of subjects requiring dopaminergic therapy, the change in Unified Parkinson's Disease Rating Scale (UPDRS) score, and the PRECEPT Study investigators' diagnosis at study termination were compared between SWEDD and DAT deficit subjects.


RESULTS
SWEDD subjects (n = 91) compared with DAT deficit subjects (n = 708) showed reduced UPDRS score at baseline (18.7 [SD 8.5] vs 25.5 [SD 10.5], p < 0.05) and minimal change in both [(123)I] β-CIT striatal binding ratio (-0.2% [SD 12.2] vs -8.5% [SD 11.9], p < 0.0001) and UPDRS score (0.5 [SD 6.9] vs 10.5 [SD 8.9], p < 0.0001) at follow-up assessments. At PRECEPT termination, the diagnosis by study investigators was changed from Parkinson disease (PD) to other disorders not associated with DAT deficit in 44% (95% confidence interval 34.2, 54.7) of SWEDD subjects compared with 3.6% (95% confidence interval 2.3, 5.1) of DAT deficit subjects.


CONCLUSIONS
These results indicate that subjects identified as having a SWEDD, with DAT imaging within the normal range, have minimal evidence of clinical or imaging PD progression. These data strongly suggest that SWEDD subjects are unlikely to have idiopathic PD.
From the Institute for Neurodegenerative Disorders (K.M., J.S., D.J.), University of Rochester (S.E., D.O.), Rochester, NY; Georgetown University (I.S.), Washington, DC; University of Toronto (A.E.L.); and Western University (C.H.), London, Ontario, Canada. kmarek@indd.org.
Kenneth
K
Marek
From the Institute for Neurodegenerative Disorders (K.M., J.S., D.J.), University of Rochester (S.E., D.O.), Rochester, NY; Georgetown University (I.S.), Washington, DC; University of Toronto (A.E.L.); and Western University (C.H.), London, Ontario, Canada.
John
J
Seibyl
From the Institute for Neurodegenerative Disorders (K.M., J.S., D.J.), University of Rochester (S.E., D.O.), Rochester, NY; Georgetown University (I.S.), Washington, DC; University of Toronto (A.E.L.); and Western University (C.H.), London, Ontario, Canada.
Shirley
S
Eberly
From the Institute for Neurodegenerative Disorders (K.M., J.S., D.J.), University of Rochester (S.E., D.O.), Rochester, NY; Georgetown University (I.S.), Washington, DC; University of Toronto (A.E.L.); and Western University (C.H.), London, Ontario, Canada.
David
D
Oakes
From the Institute for Neurodegenerative Disorders (K.M., J.S., D.J.), University of Rochester (S.E., D.O.), Rochester, NY; Georgetown University (I.S.), Washington, DC; University of Toronto (A.E.L.); and Western University (C.H.), London, Ontario, Canada.
Ira
I
Shoulson
From the Institute for Neurodegenerative Disorders (K.M., J.S., D.J.), University of Rochester (S.E., D.O.), Rochester, NY; Georgetown University (I.S.), Washington, DC; University of Toronto (A.E.L.); and Western University (C.H.), London, Ontario, Canada.
Anthony E
AE
Lang
From the Institute for Neurodegenerative Disorders (K.M., J.S., D.J.), University of Rochester (S.E., D.O.), Rochester, NY; Georgetown University (I.S.), Washington, DC; University of Toronto (A.E.L.); and Western University (C.H.), London, Ontario, Canada.
Chris
C
Hyson
From the Institute for Neurodegenerative Disorders (K.M., J.S., D.J.), University of Rochester (S.E., D.O.), Rochester, NY; Georgetown University (I.S.), Washington, DC; University of Toronto (A.E.L.); and Western University (C.H.), London, Ontario, Canada.
Danna
D
Jennings
D000328:Adult; D000368:Aged; D000978:Antiparkinson Agents / Q000627:therapeutic use; D001921:Brain / Q000000981:diagnostic imaging* / Q000378:metabolism; D050483:Dopamine Plasma Membrane Transport Proteins / Q000378:metabolism*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007980:Levodopa / Q000627:therapeutic use; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D010300:Parkinson Disease / Q000000981:diagnostic imaging* / Q000188:drug therapy / Q000378:metabolism; D011877:Radionuclide Imaging; D016032:Randomized Controlled Trials as Topic
D000978:Antiparkinson Agents; D050483:Dopamine Plasma Membrane Transport Proteins; D007980:Levodopa