[Cortical response in age-related macular degeneration (part I). Methodology and subject specificities].
OBJECTIVE
To evaluate the cortical response to visual stimulation in patients with age-related macular degeneration (ARMD).


METHODS
We conducted a prospective functional MRI study at 1.5 Testa in ten patients presenting with unilateral or bilateral ARMD and five age-matched controls. The visual stimulus was a sequence of resting phase (presentation of a fixation point on a black background) followed by an activation phase (flashes at 2 Hz). Functional data were recorded with anatomy; significant hemodynamic response secondary to neuronal activation was statistically determined using the SPM 99 software.


RESULTS
The first objective was to estimate the feasibility of a functional study in the elderly. Controls and patients complained about the duration of the examination, although each of the two active functional sessions lasted only 4.5 min. The central point fixation was impaired for the patients; some deviated their gaze to center the fixation point on a perimacular retinal area. Because of substantial movement during MRI acquisitions, the data from two patients and one control were withdrawn from statistic processing.


CONCLUSIONS
This study is one of the few evaluations reported on functional MRI in the elderly, because of technical constraints, patient fragility and their ophthalmologic pathology. Optimizing the visual stimulus and the paradigm of stimulation, repeating patient information and support have helped demonstrate significant cortical hemodynamic response in most subjects, even in the most affected patients. Evaluation of the visual cortex by functional MRI appears feasible in the ophthalmologic pathology of the elderly, providing an adapted management of the subject's conditions.
Nguyen
T-H
TH
Service de Neuro-Imagerie, CHNO des XV-XX, UPMC P6, CNRS UMR 6569, UPR 2147, Paris, France. thnguyenfr@yahoo.fr
Stievenart
J-L
JL
Saucet
J-C
JC
Le Gargasson
J-F
JF
Cohen
Y-S
YS
Pelegrini-Issac
M
M
Burnod
Y
Y
Iba-Zizen
M-T
MT
Cabanis
E-A
EA
D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D016477:Artifacts; D001931:Brain Mapping; D003627:Data Interpretation, Statistical; D017352:Echo-Planar Imaging; D005260:Female; D005403:Fixation, Ocular; D006801:Humans; D008268:Macular Degeneration / Q000503:physiopathology*; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D010775:Photic Stimulation; D013997:Time Factors; D014793:Visual Cortex / Q000502:physiology*