Development of a screening system for central visual field using the eye-tracking device\n

　Background: Visual field test with gaze movements do not require a subjective response because they are based on reflexive movements. In this study, we developed a visual field test system with gaze movements to perform a central visual field screening, and then examined the reproducibility of the measurements in healthy adult volunteers.　Methods: We examined 30 right eyes of 30 healthy volunteers (mean age, 22.7 ± 5.2 years) with a best-corrected visual acuity of at least 20/20. Gazefinder, an eye-tracking device, was used to measure gaze movements. Subjects with refractive correction were asked to follow a white target presented on a monitor. If a subject can accurately perform eye tracking with respect to the visual target, visual field with gaze movements measurements are theoretically possible in eight directions (horizontal/vertical to 15.3° and oblique to 21.5° ). After a total of three measurements, the data were quantified using analysis software (CreateChart). Finally, the intraclass correlation coefficients of the measurement values were obtained.　Results: The difference between theoretical and actual measurement values, which is thought to reflect gaze accuracy, were –0.1° ± 0.9° for upper, –0.6° ± 1.0° for upper right, –0.2° ± 1.0° for right, –0.8° ± 0.9° for lower right, –0.5° ± 0.7° for lower, –0.5° ± 0.9° for lower left, –0.6 ° ± 0.5 ° for left, and –0.6 ° ± 0.5 ° for upper left. No significant differences were found among the eight directions, and gaze accuracy was high, at within 1°. The intraclass correlation coefficients were 0.6 or higher in each direction (P < 0.01), indicating high repeatability.　Conclusions: In the traditional method for measuring visual field with gaze movements, the fixation point of view needs to be reset for each gaze movement. On the other hand, the system developed in this study has the advantage of not requiring eye movements to return to the fixation point. The present findings indicate that our newly developed system is a useful device when standard perimetry is difficult to measure

An altered GABA-A receptor function in spinocerebellar ataxia type 6 and familial hemiplegic migraine type 1 associated with the CACNA1A gene mutation

Background: Mutations in the CACNA1A gene encoding the voltage-gated calcium channel α1A subunit have been identified in patients with autosomal dominantly inherited neurological disorders, including spinocerebellar ataxia type 6 (SCA6) and familial hemiplegic migraine type 1 (FHM1). In order to investigate the underlying pathogenesis common to these distinct phenotypic disorders, this study investigated the neuronal function of the GABAergic system and glucose metabolism in vivo using positron emission tomography (PET). Methods: Combined PET studies with [11C]-flumazenil and [18F]-fluorodeoxyglucose (FDG) were performed in three FHM1 patients and two SCA6 patients. [18F]-FDG-PET using a three-dimensional stereotactic surface projection analysis was employed to measure the cerebral metabolic rate of glucose (CMRGlc). In addition, the GABA-A receptor function was investigated using flumazenil, a selective GABA-A receptor ligand. Results: All patients displayed a significant decrease in CMRGlc and low flumazenil binding in the cerebellum compared with the normal controls. The flumazenil binding in the temporal cortex was also decreased in two FHM1 patients. Conclusions: Cerebellar glucose hypometabolism and an altered GABA-A receptor function are characteristic of FHM1 and SCA6. General significance: An altered GABA-A receptor function has previously been reported in models of inherited murine cerebellar ataxia caused by a mutation in the CACNA1A gene. This study showed novel clinical characteristics of alteration in the GABA-A receptor in vivo, which may provide clinical evidence indicating a pathological mechanism common to neurological disorders associated with CACNA1A gene mutation

In vivo direct relation of tau pathology with neuroinflammation in early Alzheimer\u27s disease.

Neuronal damage and neuroinflammation are important events occurring in the brain of Alzheimer\u27s disease (AD). The purpose of this study was to clarify in vivo mutual relationships among abnormal tau deposition, neuroinflammation and cognitive impairment in patients with early AD using positron emission tomography (PET) with [C]PBB3 and [C]DPA713

Development of a screening system for central visual field using the eye-tracking device\n

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