Spatial contrast sensitivity was tested twice in normal subjects from five age groups by using each of two different psychophysical methods. Results obtained by the method of adjustment showed a decline in sensitivity with increasing age at all spatial frequencies. In contrast, the forced-choice procedure yielded results indicating an age-related decline predominantly at high spatial frequencies, with the magnitude of the decline being generally similar to that obtained earlier by a tracking method [Vision Res. 23, 689 (1983)]. The decline that we observed cannot be due to pupillary changes with age, since this factor was controlled. Moreover, we suggest that the high-spatial-frequency decline in contrast sensitivity, although it is comparatively small, is too large to be due to changes in lens density. We therefore suggest that a neural component is responsible. In addition, interactions among the age of the subject, the spatial frequency used, and the psychophysical method used suggest that the method of adjustment should be avoided for age-related studies of vision.

In normal elderly humans there is progressive motor dysfunction and loss of nigrostriatal neurons and brain dopamine similar to, although of a milder degree than, that seen in Parkinson's disease. Ten healthy elderly volunteers were given carbidopa/levodopa or placebo in a double-blind crossover study. We measured movement velocity, reaction time, tremor, visual evoked response (VER), and electroretinography (ERG). Significant changes were seen only in ERG. Motor functions and VER were unchanged. Although there appeared to be pharmacologic activity (ie, changes in ERG), levodopa, in adequate antiparkinson dosage, had no impact on the mild extrapyramidal impairment of normal elderly subjects.

We studied the neurologic abnormalities in 41 men with isolated hypogonadotropic hypogonadism. Findings included anosmia, hyposmia, mirror movements, ocular motor abnormalities, cerebellar dysfunction, and pes cavus foot deformity. One-third of the subjects had a family history of delayed sexual maturation. Patients with a family history of delayed sexual maturation had a significantly higher incidence of olfactory dysfunction, mirror movements, and pes cavus foot deformity. Our data suggest that isolated hypogonadotropic hypogonadism and its accompanying neurologic abnormalities may arise from a genetically linked developmental abnormality of CNS structures.

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SUMMARY Two groups of patients with primary Parkinsonism were studied with the ganzfeld electroretinogram (ERG): (1) seven patients who had never received dopamimetic agents, and (2) six patients given an infusion of levodopa following a period of medication withdrawal. Patients in the first category had a subtle increase in the latency of their short-wavelength sensitive cone response recorded from the retina ipsilateral to their more symptomatic side. Most patients in the second category demonstrate an improvement in their ERG when the responses recorded following levodopa infusion were compared with baseline responses obtained during the period of medication withdrawal. These results suggest that one role of retinal dopamine may be maintenance of normal retinal responsiveness to flash stimuli.Destruction of the nigrostriatal dopaminergic system is known to occur in patients with Parkinson's disease.' A more generalised defect in dopaminergic neurotransmission in Parkinson's disease has been suggested.2 One possible clinical manifestation of a more global involvement is the prolonged latency of the visual evoked potential (VEP), the extent of which has been correlated with the clinical severity of the disease.3 Two related findings suggest that the delayed VEP may be related to dopaminergic pathways in the retina. The first finding is the interocular differences in VEP latency.4 The second is that dopamine depleters and blockers increase latency of the VEP recorded over the visual cortex without altering the conduction time within the optic tract.5Compared with the VEP, a more localised evaluation of neuronal activity within the retina can be obtained with the electroretinogram,(ERG).6 Studies with rabbits show that N-methyl-phenylAddress for reprint requests: Myles Jay