Primary progressive aphasia: a case report

Correlative studies of structural and functional imaging in primary progressive aphasia

RATIONALE

To compare and contrast structural and functional imaging in primary progressive aphasia (PPA).

METHODS

A cohort of 8 patients diagnosed with PPA presenting with nonfluency were prospectively evaluated. All patients had structural imaging in the form of MRI and in 1 patient CAT scanning on account of a cardiac pacemaker. All patients had single-photon emission computed tomography (SPECT) and positron emission tomography (PET) imaging.

RESULTS

SPECT and PET imaging had 100% correlation. Anatomical imaging was abnormal in only 6 of the 8 patients. Wernicke's area showed greater peak Z score reduction and extent of area affected than Broca's area (McNemar paired test: P = .008 for Z score reduction; P = .0003 for extent). PET scanning revealed significant involvement of the anterior cingulum.

CONCLUSION

Functional imaging in PPA: (a) identified more patients correctly than anatomic imaging highlighting the importance of SPECT and PET in the diagnosis; and (b) demonstrated the heterogeneous involvement of disordered linguistic networks in PPA suggesting its syndromic nature.

Non-fluent progressive aphasia: cerebral metabolic patterns and brain reserve

Functional imaging studies suggest that brain reserve allows patients with Alzheimer's disease with more years of schooling to cope better with brain damage. No studies exist on patients with non-fluent progressive aphasia (NFPA). We aimed to explore metabolic patterns of patients with NFPA and to provide evidence for brain reserve in NFPA. 11 right-handed patients with NFPA and 16 age-matched controls underwent (18)F-FDG PET imaging. Scans of patients and controls were compared in SPM2. A linear regression analysis with glucose metabolism as dependent variable and years of schooling as the independent variable, adjusted for age, gender, and a total score of the CERAD neuropsychological battery was conducted. The NFPA group showed a hypometabolism of the left hemisphere including the middle frontal, and inferior temporal and angular gyri, and the bilateral caudate nuclei and thalami (p(corr)<0.05). The regression analysis revealed a significant inverse association between education and glucose metabolism in the left inferior temporal, parahippocampal, and supramarginal gyri (p(corr)<0.05). We conclude that brain reserve is also present in NFPA.

Is slowly progressive anarthria a "pure" motor-speech disorder? Evidence from writing performance

It is usually assumed that writing is normal in patients with anarthria, but a careful examination of the literature shows that they produce deletions, transpositions and insertions. Indeed, a matter of debate concerns the distinction between primary progressive aphasia (PPA) and slowly progressive anarthria (SPA). If writing deficits were purely linguistic errors, then there would be no reason to consider slowly progressive anarthria as distinct from non-fluent PPA. We report the case of a patient with SPA in whom writing abilities were specifically assessed. No lexical-semantic deficits were detected, but errors were deletions, substitutions or transpositions, with no frequency, length or lexicality effect; moreover, controls produced the same kind of errors during articulatory suppression. It is suggested that subvocal rehearsal plays a role in writing, allowing the conversion/assembly of the phonological string in a graphemic representation. Therefore, writing deficits do not appear to have a linguistic basis and SPA seems distinguishable from nonfluent forms of aphasia.