Photophobia in essential blepharospasm--a positron emission tomographic study.

To localize regional alterations in cerebral glucose metabolism in essential blepharospasm (EB) patients with photophobia. We have studied 22 EB patients by performing positron emission tomography and [(18)F]-fluorodeoxyglucose analysis. The patients were classified into two subgroups, namely, EB with photophobia (P group) and EB without photophobia (NP group), and compared with a healthy control group (n = 44). There were no significant differences between the two patient groups with respect to the severity of motor symptoms or the duration for which the condition persisted. The FDG-PET images were analyzed using the statistical parametric mapping software. As compared to the control group, the P group exhibited significant hypermetabolism in the thalamus (P = 0.002), while the NP group exhibited significant hypometabolism in the dorsal midbrain, especially, in the superior colliculus (P = 0.005). The P group exhibited significant hypermetabolism in the thalamus and the dorsal midbrain as compared to the NP group (P < 0.001). These findings suggest that photophobia in EB patients may be associated with abnormal hyperactivity in the thalamus. Either hyperactivity of the thalamus or hypoactivity of the superior colliculus, or both may be associated with excessive blinking in these patients.

Measurement of the 11C-flumazenil binding in the visual cortex predicts the prognosis of hemianopia.

In order to determine whether functional neuroimaging studies can predict the prognosis of hemianopia due to organic cerebral disorders, we studied 8 patients (6 men and 2 women; age, 56.0+/-8.6 years) with homonymous hemianopia and compared them with 15 normal subjects (6 men and 9 women; age, 54.3+/-4.4 years). The cerebral glucose metabolism and 11C-flumazenil (FMZ) binding were measured by positron emission tomography, more than 1 month after the onset of the condition. Bilateral regions of interest (ROIs) were selected in the striate cortex, extrastriate cortex, cuneus and thalamus. Further, semi-quantitative data on the cerebral glucose metabolism and FMZ binding were obtained for the ROIs and compared with the data obtained for homologous regions in the contralateral hemisphere by calculating the ipsilateral/contralateral (I/C) ratio. The I/C ratios for the cerebral glucose metabolism and FMZ binding in the striate cortex were significantly low in the patients (glucose metabolism, P<0.0005; FMZ binding, P<0.005), while the ratio for the FMZ binding in the cuneus increased (P<0.0005). We observed that 5 patients, whose I/C ratio for the FMZ binding in the striate cortex was >0.850, experienced an improvement in their visual field, while that 3 patients with lower I/C ratios did not. The FMZ-PET may be useful to predict the prognosis of hemianopia in the chronic phase.