No abstract

Pattern reversal evoked potentials (PREPs) were recorded in 51 normal elderly subjects (27 males. 24 females). Elderly females had shorter P100 and N150 latencies, greater P100‐N150 amplitudes, and higher noise power than elderly males. The N150 latency differences were significant even when P100 latency effects were partialled out statistically. Gender differences in P100‐N150 amplitude Mere independent of both noise power and PREP latency measures. These results provide evidence that, in the elderly, 1) gender differences in PREP amplitude reflect factors specific to CNS processing of visual stimuli rather than global CNS anatomic or physiological factors, 2) gender differences in P100 latency reported in younger groups are also present in the elderly, and 3) there are separable factors underlying gender differences in N150 and P100 latencies in the elderly.

A modification of the Fuld Object-Memory Evaluation (FOME) test was developed for use with middle-aged adults. To avoid the ceiling effect which occurs when the 10-item FOME is used with adults in this age group, we made the test more difficult by increasing the number of items to 15. We obtained preliminary data on the 15-item version of the test by administering it to 32 healthy, well-educated adults aged 35 to 55. This version of the test was difficult enough so that even high functioning adults needed multiple trials to memorize all items. No sex differences, and no significant correlations with education or age for any aspect of test performance were found. We present mean scores for recall on each trial, as well as averaged scores for storage, retrieval, consistent retrieval, and recall failure across five trials.

There are serious methodological problems in studies which report contralateral visual masking. Contralateral masking occurs when detection of a hemifield target stimulus is impaired by a pattern-masking stimulus presented to the opposite hemifield. We demonstrate that, in studies which used positive stimuli (i.e., black letters on a white field), contralateral masking may be an artifact. Although we observed contralateral masking when positive stimuli were presented, there was no evidence of masking with negative stimuli (i.e., white letters on a black field). A special masking stimulus with a positive mask contralateral to the target and a black hemifield ipsilateral to the target also failed to produce masking. Contralateral masking in this experiment was due to the flash of light in the field ipsilateral to the target; it was this ipsilateral stimulation, rather than contralateral interference, which impeded target recognition.