| Individuals diagnosed with multiple sclerosis (MS) are often vulnerable to distractibility when presented with attention tasks which contain interfering stimuli. Since many MS patients report memory problems, it is possible that many of the difficulties in memory are related to, or due to, deficits in attention.;One well-documented index of attention is the P300 event-related potential component, which occurs with attention to a target stimulus. To investigate the role of the P300 in attention and gating processes, P3a and P3b components from MS-diagnosed individual and normal controls were measured in auditory and visual attention tasks with interference or non-interference. For the interference conditions, attention tasks contained either intramodal or cross-modal distracters.;Behavioral results showed no significant difference in response accuracy between the MS and Control group for either non-interference or interference tasks requiring focused or selective attention, however, there were significant effects on P3a and P3b amplitude and latency for the MS group. Due to demyelinating processes in the MS group, latencies for the P3a and P3b components were longer. The P3b component, which is considered to be reflective of attention, was overall significantly lower in amplitude for the MS group compared to the Control group. The P3a component, which is related to the orienting response, was also higher for the MS group compared to the Control group. The relatively higher P3a amplitude of the MS group indicates some involuntary attention to interfering stimuli, possibly a sign of distractibility.;With respect to the major findings above, it is suggested that MS-diagnosed individuals may not experience great difficulty in attending to simple stimuli in a quiet environment. They may be prone to distractibility, however, when trying to attend to stimuli in more complex, noisy surroundings. |
