Functional mapping in PD and PSP for sustained phonation and phoneme tasks

Abstract

Aim To elucidate the central basis of articulatory speech disorders in Parkinsonian syndromes using functional magnetic resonance imaging (fMRI). Methods Twenty-two patients with Parkinson's disease (PD) and 18 with progressive supranuclear palsy (PSP) were clinically evaluated for speech dysfunction. Functional magnetic resonance imaging (fMRI) was carried out in these patients using sustained phonation and phoneme tasks. Individual and group analysis using SPM2 was done for eight patients with PD, 7 with PSP and 6 healthy controls. Setting Tertiary Medical Teaching Institute. Results For sustained phonation paradigm, superior temporal gyrus area was activated in PD patients, and occipital cortex in PSP subjects in comparison to controls. For phoneme paradigm, the patients with PD recruit lingual gyrus obviating the need for more efforts for the task. Also wider areas as well as more clusters were activated in PD patients compared to controls. Lingual gyrus was found to be strongly activated in PSP patients. Reduced activation of the primary areas with recruitment of remote areas was another prominent finding in PSP. Due to excessive motion (> 1.5 mm, > 1°) in all the MSA patients, they could not be considered for analysis. Conclusion The failure of the executive fronto-striatal network would lead to increased activation of other areas in PD, but in PSP, there is a widespread cortical dysfunction.