The heterogeneity of early Parkinson's disease: a cluster analysis on newly diagnosed untreated patients.
BACKGROUND
The variability in the clinical phenotype of Parkinson's disease seems to suggest the existence of several subtypes of the disease. To test this hypothesis we performed a cluster analysis using data assessing both motor and non-motor symptoms in a large cohort of newly diagnosed untreated PD patients.


METHODS
We collected data on demographic, motor, and the whole complex of non-motor symptoms from 100 consecutive newly diagnosed untreated outpatients. Statistical cluster analysis allowed the identification of different subgroups, which have been subsequently explored.


RESULTS
The data driven approach identified four distinct groups of patients, we have labeled: 1) Benign Pure Motor; 2) Benign mixed Motor-Non-Motor; 3) Non-Motor Dominant; and 4) Motor Dominant.


CONCLUSIONS
Our results confirmed the existence of different subgroups of early PD patients. Cluster analysis revealed the presence of distinct subtypes of patients profiled according to the relevance of both motor and non-motor symptoms. Identification of such subtypes may have important implications for generating pathogenetic hypotheses and therapeutic strategies.
Sobell Department of Motor Neuroscience and Movement Disorders, University College London (UCL), London, United Kingdom.
Roberto
R
Erro
Carmine
C
Vitale
Marianna
M
Amboni
Marina
M
Picillo
Marcello
M
Moccia
Katia
K
Longo
Gabriella
G
Santangelo
Anna
A
De Rosa
Roberto
R
Allocca
Flavio
F
Giordano
Giuseppe
G
Orefice
Giuseppe
G
De Michele
Lucio
L
Santoro
Maria Teresa
MT
Pellecchia
Paolo
P
Barone
D016000:Cluster Analysis; D015331:Cohort Studies; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009043:Motor Activity; D010300:Parkinson Disease / Q000175:diagnosis* / Q000503:physiopathology*; D010641:Phenotype