Visuo-spatial processing is linked to cortical glutamate dynamics in Parkinson’s disease

Anja Ophey, Ezequiel Farrher, Nora Pagel, Aline Seger, Christopher E. J. Doppler, N. Jon Shah, Elke Kalbe, Gereon R. Fink, Michael Sommerauer

10th April 2023

Parkinson’s disease (PD) is the second most frequently diagnosed neurodegenerative disorder today and is caused by the accumulation of α-synuclein in widespread brain areas. In addition to the classic motor symptoms generally associated with PD, cognitive decline is also known to impact around 40% of patients, and up to 80% of these patients eventually develop PD dementia. Scientists believe that metabolic alterations observed in the occipital cortex during visual processing may serve as a biomarker for cognitive decline in patients with PD. Using functional magnetic imaging spectroscopy (MRS), this study aimed to investigate early metabolic alterations of glutamate metabolism in the occipital cortex during visual processing in PD patients.

Functional MRS measurements were performed on 16 PD patients and 10 healthy controls using a 7 Tesla MRI machine and a visual checkerboard stimulation. Glutamate metabolite levels during rest versus stimulation were compared along with correlates of the functional MRS response with performance in visuo-cognitive tests.

The results of the study indicate that functional MRS can capture even subtle differences in neural processing that are linked to behavioural performance. These would have been missed by conventional, static MRI, thus underlining the potential of functional MRS as a tool for studying molecular alterations at high sensitivity.

Future work will now focus on evaluating the prognostic potential of the technique in longitudinal studies with a view to its use in earlier diagnosis and individual treatment decisions.

Original publication: Visuo-spatial processing is linked to cortical glutamate dynamics in Parkinson’s disease — a 7-T functional magnetic resonance spectroscopy study