Amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD)
Until a few years ago, amyotrophic lateral sclerosis or ALS was considered a neurodegenerative disease that caused a progressive loss of strength with preservation of intellectual functions. However, in recent years we have learned that patients with ALS can frequently present with cognitive and personality changes that may resemble those seen in frontotemporal dementias, another group of neurodegenerative diseases that cause progressive personality change or language impairment.
The lack of recognition of cognitive and behavioral changes in patients with ALS can be explained by several reasons, including the scarcity of instruments adapted for these patients (who often have problems speaking or writing) and the lack of precision of the conventional neuroimaging measures to capture brain changes in these patients.
In the study entitled “Cortical microstructure in the amyotrophic lateral sclerosis-Frontotemporal dementia continuum” recently published in the journal Neurology, result of the collaboration between the Sant Pau Memory Unit and the Neuromuscular Disorders Unit at the Hospital de Sant Pau, we analyzed the brain changes that occur in these diseases using a novel radiological technique.
What have we done in this study?
In this study, we have characterized the cognitive and behavioral changes in a group of patients with ALS and frontotemporal dementias diagnosed at the Hospital de Sant Pau. In addition, we performed a brain MRI to measure the first brain changes that occur in neurodegenerative diseases with a new brain MRI technique, the measurement of cortical mean diffusivity.
The main finding of this work was that patients with cognitive or behavioral changes showed brain changes in the frontal and temporal regions that resemble those seen in frontotemporal dementias. In addition, cognitive performance showed an association to the brain changes detected with this new technique.
Relevance of the study
This study confirms that cognitive and behavioral disturbances in ALS are due to changes in the frontal and temporal regions of the brain. Cortical mean diffusivity is useful to quantify these changes and understand how they affect the clinical progression of patients with ALS. Likewise, we hope that this information contributes to the improvement of the diagnosis and the design of clinical trials that allow testing new treatments for ALS.