Brainstem atrophy is linked to extrapyramidal symptoms in frontotemporal dementia

Brainstem atrophy is linked to extrapyramidal symptoms in frontotemporal dementia
Hypometabolism in EP + patients compared to EP− patients in the whole cohort. Orange and yellow colors represent lower metabolism in the EP + group (p < 0.001, uncorrected). Images are presented in neurological orientation (i.e., left hemisphere presented in left side of the picture). Credit: Journal of Neurology (2022). DOI: 10.1007/s00415-022-11095-x

Frontotemporal dementia patients with extrapyramidal symptoms have brainstem atrophy and reduced metabolism in certain areas of the brain significantly more often than patients without extrapyramidal symptoms, a new study from the University of Eastern Finland shows. This observation can facilitate differential diagnostics in frontotemporal dementia. The findings were published in the Journal of Neurology.

Frontotemporal , FTD, is an umbrella term for that affect behavior and cognition. Sometimes, FTD comes with extrapyramidal symptoms, such as those in Parkinson's disease, and this makes the diagnosis of FTD challenging. However, the new study now shows that accurate imaging and analysis of the brain may make it possible to distinguish between FTD and other diseases that cause extrapyramidal symptoms.

Extrapyramidal symptoms refer to involuntary movements, typically tremor, slowness, stiffness, loss of facial expressions and automatic movements, such as arm swing when walking. They are often associated with extrapyramidal disorders such as Parkinson's disease and atypical parkinsonism. Examples of atypical parkinsonism include (PSP) and corticobasal degeneration (CBD). They share disease mechanisms with , which is why they are nowadays considered to be part of the same spectrum of diseases. Frontotemporal dementia is traditionally divided into two main categories: the more common variant with behavioral changes as an early symptom, and the rarer primary progressive aphasia (PPA) with problems related to speech as an early symptom.

Neurodegeneration associated with progressive memory disorders is typically imaged in two ways: magnetic resonance imaging of the brain provides accurate information on brain structures and volumes of the different parts of the brain, whereas , or a PET scan, provides information on metabolism in different areas of the brain. Degeneration of the brain tissue is often preceded by slow or missing metabolism.

The researchers analyzed Kuopio University Hospital's medical records on a total of 139 patients with frontotemporal dementia, PSP or CBD, focusing in particular on their diagnosis and the presence of extrapyramidal symptoms. The patients' MRI and PET images were analyzed using automated analysis software.

The researchers found that patients with extrapyramidal symptoms also had atrophy of the basal ganglia in the midbrain, and of the brainstem. When looking at patients with frontotemporal dementia alone, it was found that patients with extrapyramidal symptoms had brainstem atrophy considerably more often than patients without extrapyramidal symptoms. In addition, PET image analyses showed reduced metabolism in the superior cerebellar peduncle and the frontal lobes in patients with extrapyramidal symptoms.

The study showed, for the first time, that significant structural and metabolic differences can be detected in the brain of frontotemporal dementia patients with extrapyramidal symptoms, compared to patients without these symptoms.

"If our findings are confirmed in other cohorts, they can be used in early diagnostics to distinguish between frontotemporal dementia and Parkinson's disease, for example. These findings will also provide us with a better understanding of the mechanisms of these diseases," says Doctoral Researcher Sami Heikkinen, the lead author of the article.

"Although the treatment of these diseases is symptomatic at the moment, an early and accurate diagnosis is an important step towards the development of disease modifying treatments."

More information: Sami Heikkinen et al, Brainstem atrophy is linked to extrapyramidal symptoms in frontotemporal dementia, Journal of Neurology (2022). DOI: 10.1007/s00415-022-11095-x

Citation: Brainstem atrophy is linked to extrapyramidal symptoms in frontotemporal dementia (2022, April 7) retrieved 29 September 2023 from
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