We thank Dr. Abe for his interest and relevant
suggestions. The aim of our study was to characterize the natural
history of primary progressive aphasia (PPA) based on clinical data, not
on imaging. We looked back to the imaging data available in the files of
the cohort patients. Although all patients underwent CT or MRI and most had SPECT scans, we could find only 22 SPECT, 21 CT and 16 MRI scans,
since patients kept imaging performed outside the center. Scans were read
by two independent raters, blinded to clinical data, using a semi-quantitative 0-2 scale.
As suggested by Dr. Abe, we distinguished two groups
of patients: those with atrophy or uptake decreased most severe in frontal
regions (F-PPA, n=12), and those with most severe perisylvian impairment
(P-PPA, n=11). Results were concordant for structural and functional
imaging. All patients had a left hemisphere predominance of the lesions
except one right-handed woman with a right atrophy and uptake decrease
(crossed-aphasia). The more recent imaging displayed more symmetrical
lesions.
In the F-PPA group, eight patients were non-fluent and four were fluent,
mean age at onset was 61.7 (5.9) years, and mean delay between onset and first
visit was 3.0 (1.8) years. In the P-PPA group, six patients were fluent, four
were non-fluent (it could not be determined in one patient), mean age at
onset was 62.6 (6.0) years, and mean delay between onset and first visit was
3.6 (2.7) years. The two groups did not differ on these characteristics.
The difference was not statistically significant for progression to one
syndrome or another (frontotemporal dementia: F-PPA: 10/12, P-PPA: 6/11;
dementia with Lewy bodies: F-PPA: 1/12, P-PPA: 3/11; corticobasal
degeneration: F-PPA: 1/12, P-PPA: 2/11), for entry an institution,
survival, and for loss of autonomy.
Thus, PPA patients who initially had more frontal atrophy or uptake
decrease tended to be more non-fluent at first visit than those with
initially more perisylvian impairment, but did not differ significantly
for survival and loss of autonomy. As shown previously [1], patients with
a fluent form of aphasia tended to have a better prognosis, especially
concerning survival and swallowing difficulties and to a lesser extent, entry an institution, mutism, walking, toilette and dressing, urinary
incontinence, and eating.
According to these results, we cannot assert
that there are different natural histories of PPA based on the initial
location of the degeneration, frontal or perisylvian.
Acknowledgements: We thank Drs JY Gauvrit, X. Leclerc, A. Emptaz, M.
Steinling and for assessing CT, MRI and SPECT scans.
Disclosure: The authors report no conflicts of interest.