Simultaneous recording of pattern electroretinography and visual evoked potentials in multiple sclerosis. A method to separate demyelination from axonal damage to the optic nerve
G. G. Celesia, D. Kaufman and S. B. Cone
Pattern electroretinograms (P-ERGs) and visual evoked potentials (VEPs)
were recorded in 35 patients with multiple sclerosis and in 35 age-matched
normal subjects. Four patterns of abnormalities were noted in the group
with multiple sclerosis. The most frequent abnormality consisted of the
following: normal P-ERG, delayed P100, and prolonged interpeak interval
between the b-wave of the P-ERG and P100 (retinocortical time). This
pattern indicates demyelination of the optic nerve. A second pattern
consisted of absent P-ERG and absent VEP. This pattern was associated with
optic atrophy and/or central scotoma, indicating severe optic nerve
axonopathy with retrograde degeneration of ganglion cells. A third pattern
consisted of normal P-ERG and absent VEP, suggesting a total block of
transmission at the optic nerve. A fourth pattern consisted of present but
low-amplitude P-ERG, delayed VEP, and prolonged retinocortical time,
indicating a demyelinating process with partial axonal involvement. The
concomitant use of P-ERG and VEP results in a better classification of the
type and severity of dysfunction affecting the optic nerve. The prognostic
value of the four patterns for recovery of visual function is discussed.
