PubMed · 4094873
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E H Galluscio. 1985. Brain laterality and dual-task performance.. https://doi.org/10.2466/pms.1985.61.3f.1290
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We report a diagnostic sign of ulnar neuropathy. Function of the interossei is tested by asking the patient to hold a sheet of paper between the middle and ring fingers, by adducting the fingers while the examiner pulls it firmly away. The metacarpophalangeal joints will flex more on the affected side as the flexor tendons are recruited. This test can easily detect muscle weakness in the early stage of ulnar neuropathy, and is produced by a similar mechanism to that of Froment's sign.
The capacity of visual working memory was investigated using abstract images that were slightly distorted NxN (with generally N=8) square lattices of black or white randomly selected elements. After viewing an image, or a sequence of images, the subjects viewed couples of images containing the test image and a distractor image derived from the first one by changing the black or white value of q randomly selected elements. The number q was adjusted in each experiment to the difficulty of the task and the abilities of the subject. The fraction of recognition errors, given q and N was used to evaluate the number M of bits memorized by the subject. For untrained subjects, this number M varied in a biphasic manner as a function of the time t of presentation of the test image: it was on average 13 bits for 1 s, 16 bits for 2 to 5 s, and 20 bits for 8 s. The slow pace of acquisition, from 1 to 8 s, seems due to encoding difficulties, and not to channel capacity limitations. Beyond 8 s, M(t), accurately determined for one subject, followed a square root law, in agreement with 19th century observations on the memorization of lists of digits. When two consecutive 8x8 images were viewed and tested in the same order, the number of memorized bits was downshifted by a nearly constant amount, independent of t, and equal on average to 6-7 bits. Across the subjects, the shift was independent of M. When two consecutive test images were related, the recognition errors decreased for both images, whether the testing was performed in the presentation or the reverse order. Studies involving three subjects, indicate that, when viewing m consecutive images, the average amount of information captured per image varies with m in a stepwise fashion. The first two step boundaries were around m=3 and m=9-12. The data are compatible with a model of organization of working memory in several successive layers containing increasing numbers of units, the more remote a unit, the lower the rate at which it may acquire encoded information.
BACKGROUND: Peripapillary height measurements are possible using 2 different reference planes of the Heidelberg-Retina-Tomograph. It is not tested yet, whether the extent of glaucoma damage should be better quantified using reference plane 1 or 2. PATIENTS AND METHODS: In 32 eyes of 32 glaucoma patients with a defined up-down asymmetry of visual field loss is tested I.) if there is a significant correlation between peripapillary height and visual field loss comparing reference plane 1 and 2. II.) if there is a conformable up-down asymmetry of the peripapillary height using a new "retinal-asymmetry-difference" (RAD). III.) if conformity between peripapillary height and visual field loss depends on the distance from the disc margin. RESULTS: 1.) For an advanced visual field loss there was a significant correlation between visual field loss and peripapillary height using reference plane 1. II.) In eyes with a big up-down asymmetry of visual field loss there was a bigger conformity between the up-down asymmetry of visual field loss and the up-down asymmetry of peripapillary height (11 of 12 eyes), as for a small up-down asymmetry (12 of 20 eyes). III.) Conformity decreases with the distance from the disc margin. CONCLUSIONS: Peripapillary height should be examined using measurement circles near the disc margin. Because of its independence on the age and on different reference planes additional calculation of an up-down "retinal-asymmetry-difference" (RAD) seems to be useful. Using this up-down "retinal-asymmetry-difference" (RAD) a big up-down asymmetry of visual field loss, equivalent to an advanced glaucomatous disease, is quantified with high sensitivity.