Background
Amyotrophic Lateral Sclerosis (ALS) is characterized by a spectrum of phenotypes, but a few study
addressed the presence of parkinsonian (PK) symptoms.
Aim of our study was to investigate the occurrence of PK features in a prospective population-based
cohort of ALS patients, determining their demographic, clinical, neuropsychological and genetic
characteristics, and identifying their morphological and functional imaging correlates.
Methods
A consecutive series of ALS patients were enrolled and prospectively followed for two years.
Patients were classified according to the presence (ALS-PK) or absence (ALS) of PK signs, and
they underwent neuropsychological testing, genetic analysis for the main ALS and PD genes, brain
MRI and 18F-FDG-PET. ALS-PK patients underwent 123I-ioflupane SPECT
Results
Out of 114 eligible patients, 101 (64 men; mean age at onset 65.1 years) were recruited. Thirty-one
patients (30.7%) were classified as ALS-PK. Compared to ALS patients, ALS-PK patients were
more frequently male, but did not differ for any other clinical, demographic or neuropsychological
factor. 123I-ioflupane SPECT was normal in all but two ALS-PK patients. At 18F-FDG-PET, ALSPK
patients showed a relative hypometabolism in left cerebellum and a relatively more preserved
metabolism in right insula and frontal regions; MRI fractional anisotropy was reduced in the sagittal
stratum and increased in the retrolenticular part of the internal capsule.
Conclusions
In our study about 30% of ALS patients showed PK signs. Neuroimaging data indicate that PK
signs are due to the involvement of brain circuitries other than classical nigrostriatal ones,
strengthening the hypothesis of ALS as complex multisystem disease.
