Decreasing B-wave amplitude noted in erg in one type of retinitis pigmentosa.

Electroretinographic studies have been helpful in differentiating human forms of retinitis pigmentosa inherited by different patterns. The prognosis appears to be correlated with the mode of inheritance. The recessively inherited form along with the x-linked and dominantly inherited with reduced penetrance type of inheritance are associated with more severe forms of the disease than is the dominantly inherited with complete penetrance. The underlying biochemical defects have not been identified. Human pathological specimens early in the disease have been almost nonexistent. Animal models have been identified but correlation with human disease has been markedly limited [1]. Electrophysiology and recent technology offer some prospect for differentiating responsible abnormalities and offer a noninvasive evaluation of the disease process and treatment. Three cases of dominantly inherited retinitis pigmentosa with complete penetrance are presented. These show a decreasing B-wave amplitude on successive photopic evaluations using fast random stimuli.

First-order Wiener kernel visually evoked potentials obtained from multiple sclerosis patients.

Visually evoked potentials (VEP) were measured in multiple sclerosis patients with five sizes of reversing check stimuli. The VEPs were obtained using random binary sequence triggered check reversals. The random binary sequence was cross-correlated with scalp potential responses to obtain the estimates of the linear response of the system. For each evaluation a series of five VEPs, one for each of five check sizes, was done. A correlation coefficient was calculated to evaluate check size versus amplitude of the major negative wave. A tabulation was made to compare Snellen chart visual acuity with these correlation coefficients. For the eyes with a Snellen acuity of 20/20, 63% of the VEP amplitudes increased as the check size was decreased with correlation coefficients of -0.6 to -1. For the eyes with a Snellen acuity of 20/70 or less the amplitude decreased with the check size decrease, showing a correlation coefficient of +0.6 to +1 in 45% of the evaluations. The check size giving the largest amplitude was also tabulated with respect to the visual acuity, but did not appear to have as strong a relationship to visual acuity.

Age-related changes in the first order Weiner kernel visual evoked potential.

Visual evoked potentials were obtained from 112 subjects (215 eyes) aged 5 to 79 years with fast random stimuli. The stimulus (the presence or absence of the initiation of a reversal) and response (voltage measurements) were used in calculating the first order Wiener kernels to obtain the visual evoked potentials. Five check sizes were used to stimulate each eye. The implicit time of the major negative wave showed a significant increase with age for each check size used. Regression lines for the implicit time vs age data for male subjects were significantly different from those of females. The y-intercepts were lower and the slope of the regression lines were consistently steeper for males. Thus the rate of increase in implicit time was higher in males. The relationship of the amplitude of the major wave to age did not appear to be linear. The data suggested that a second-order polynomial curve might be an appropriate representation of the relationship.