On the clinical application of P300.
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Arousal↗
Biomedical subjects
J Polich
Publications and source records attributed to J Polich.
Comparison of infant and adult P300 from auditory stimuli.
Event-related brain potentials (ERPs) using auditory stimuli were recorded from 5- to 10-month-old infants and normal young adults with a passive tone sequence paradigm. A P3 (P300) component was obtained which demonstrated the same central-parietal maximum scalp distribution for both subject groups. P3 amplitude was smaller and its peak latency longer for infants compared to those of the adults across all electrode sites. P3 measures remained stable across stimulus trials indicating that ERP habituation was not occurring. Evaluation of individual subjects suggests that the P3 can be elicited from infants with auditory stimuli in a manner similar to that from adults and may serve as a useful index for the assessment of cognitive function in infants.
Acoustic Stimulation↗
P300 in multiple sclerosis: a preliminary report.
The P300 component of the event-related brain potential (ERP) elicited with auditory stimuli and pattern-shift visual evoked potentials (VEPs) was obtained from 16 patients with multiple sclerosis (MS) and 16 matched control subjects. P300 latency was significantly longer and component amplitude relatively depressed in the MS patients compared to control subjects. The P100 potential of the VEP also was delayed for both full-field and half-field stimulus conditions in the patients compared to control subjects. The findings suggest that the P300 ERP may reflect the cognitive decline associated with MS.
Adult↗
P300, probability, and introverted/extroverted personality types.
Extreme introverted and extroverted subject groups (n = 24 each) containing equal numbers of male and females were assessed with the P300 (P3) component of the event-related potential (ERP). A two-tone auditory discrimination task in which the probability of the target stimulus varied systematically in different conditions (.20, .40, .60, .80) was used to elicit the ERPs. The P3 amplitude demonstrated a significant interaction between personality type, probability, and subject gender and was generally smaller for introverts than for extroverts. Female subjects tended to have larger overall P3 components than male subjects. P3 latency was not affected by the personality variable. The results support previous findings for ERP differences between introverts and extroverts and suggest that personality type differentially influences target stimulus probability effects. The findings are discussed in terms of individual differences in cortical activity on P3 amplitude and personality measures.
Adult↗
P300, food consumption, and memory performance.
The effects of food intake on the P300 (P3) component of the event-related brain potential (ERP) were assessed in two studies. Experiment 1 compared 24 subjects who had not eaten within 6 hours of testing with 24 subjects who had consumed food within 3 hours of testing. P3 target stimulus amplitude was reduced significantly for the subjects who had not eaten relative to those who had eaten, whereas peak P3 latency was only moderately affected by the recency of food consumption over task conditions. In Experiment 2, P3 measurements, memory performance in a word recall task, and blood glucose levels were obtained from 24 subjects at three different times: 1) after a 14-hour fast, 2) 5 min after consuming lunch, and 3) 30 min after consuming lunch. P3 target stimulus amplitude increased initially after food intake and decreased slightly at the third measurement time, while peak P3 latency became somewhat shorter immediately after food intake but then returned to baseline. Recall for recently presented items mimicked the P3 amplitude changes, whereas blood glucose levels increased monotonically across food conditions. The results from both studies suggest that: 1) target stimulus P3 amplitude is affected by the recency of food intake; 2) food-related P3 amplitude changes appear related to memory function; and 3) subjects should eat within several hours before ERPs are acquired to ensure that P3 component measurements reflect values indicative of normal bodily functioning.
Acoustic Stimulation↗
P300 and individual differences: morning/evening activity preference, food, and time-of-day.
To determine how individual differences stemming from activity preference, previous food intake, and time-of-day affect the P300 or P3 event-related brain potential (ERP), subject groups who varied orthogonally on these factors were compared using a simple auditory discrimination task to elicit the ERPs. Amplitude of the P3 component for morning-preferring subjects who had eaten recently was relatively large for both the morning and evening measurement time groups. P3 amplitude for the morning-preferring subjects who had not eaten recently was large for those measured in the morning and relatively small for those subjects measured in the evening. For evening-preferring subjects who had eaten recently, P3 amplitude was again relatively large for both the morning and evening measurement time groups. Evening-preferring subjects who had not eaten recently produced very small P3 components for those measured in the morning compared to the large components produced by those subjects measured in the evening. P3 latency tended to be longer for all subjects who had not eaten recently compared to those who had. The results suggest that the P3 component is sensitive to physiological and psychological changes originating from individual differences related to bodily state, which perhaps stems from individual differences in arousal level.
Adolescent↗
The effects of hemispheric differences on feature perturbations.
Hemispheric differences for feature perturbations were investigated in two experiments. Stimulus displays consisting of five small squares arranged in a single row were presented tachistoscopically, with the subject instructed to state in which square a horizontal tick mark was located. Ticks could occur in any of the three middle squares, with half of the ticks presented on the inside and half presented on the outside of the square in relation to the fovea. Experiment 1 presented each array of five squares to the right or left of fixation at one of three distances from the fovea. Experiment 2 manipulated the distance between the squares and kept foveal distance constant. In each experiment, fewer errors were made when stimuli were presented to the left visual field/right hemisphere than when they were presented to the right visual field/left hemisphere, when ticks migrated toward the fovea. Experiment 1 found that increasing the distance from the fovea increased the error rate, but did not change the hemispheric differences. Experiment 2 found that increasing the distance between the squares did not change hemispheric effects reliably. The data imply that hemispheric differences for perceptual processing begin very early during sensory analysis.
Adult↗
P300 from auditory and somatosensory stimuli: probability and inter-stimulus interval.
The P300 (P3) event-related brain potential (ERP) was elicited with auditory and somatosensory stimuli using an easy discrimination task in two experiments. Experiment 1 manipulated target stimulus probability (0.20 vs. 0.80). Experiment 2 manipulated inter-stimulus interval (2 s vs. 6 s) for both stimulus modalities in different conditions while keeping target probability constant. Probability and inter-stimulus interval had similar effects for auditory and somatosensory stimuli, with lower probability and longer inter-stimulus intervals producing larger P3 amplitudes. No statistically reliable differences in scalp distribution between modalities were obtained, with both modalities producing maximal amplitudes at Pz. The results suggest that auditory and somatosensory stimuli when used in a relatively easy discrimination task yield the same overall P3 values.
Acoustic Stimulation↗
P300 and introverted/extraverted personality types.
The P300 component of the event-related potential elicited with a two-tone auditory discrimination task and two-trial block replication procedure was obtained from 16 introverted and 16 extraverted undergraduate students. P300 demonstrated no overall significant effects for either the personality variable or the block variable. However, P300 amplitude to the target stimuli declined significantly between Block 1 and Block 2 for the extraverted subjects, but did not change across trial blocks for the introverted group. Female subjects tended to have larger P3 amplitudes than male subjects, but this factor did not interact with either the personality variable or the trial block variable. The results suggest that P3 amplitude habituates more rapidly for extraverts than for introverts.
Adult↗
P300 in the evaluation of aging and dementia.
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Aged↗
Hemispheric differences in visual search of simple line arrays.
The effects of perceptual organization on hemispheric visual-information processing were assessed with stimulus arrays composed of short lines arranged in columns. A visual-search task was employed in which subjects judged whether all the lines were vertical (same) or whether a single horizontal line was present (different). Stimulus-display organization was manipulated in two experiments by variation of line density, linear organization, and array size. In general, left-visual-field/right-hemisphere presentations demonstrated more rapid and accurate responses when the display was perceived as a whole. Right-visual-field/left-hemisphere superiorities were observed when the display organization coerced assessment of individual array elements because the physical qualities of the stimulus did not effect a gestalt whole. Response times increased somewhat with increases in array size, although these effects interacted with other stimulus variables. Error rates tended to follow the reaction-time patterns. The results suggest that laterality differences in visual search are governed by stimulus properties which contribute to, or inhibit, the perception of a display as a gestalt. The implications of these findings for theoretical interpretations of hemispheric specialization are discussed.
Adult↗
Hemispheric local/global processing revisited.
Hemispheric differences for local and global processing were assessed with square and rectangular stimulus shapes which contained either squares or rectangles within them. Experiment 1 manipulated the overall size and area of the stimulus items, while experiment 2 kept stimulus area constant and manipulated the number of shapes inside the stimulus. In different conditions subjects judged whether the inside shapes (local processing) or whether the outside shapes (global processing) were squares or rectangles. Reaction time measures revealed that hemispheric differences were unrelated to the local or global processing requirements as well as the spatial frequency of the stimulus texture. A left hemisphere advantage generally was obtained across stimulus and processing conditions, with the pattern of task effects dependent on the specific stimuli employed. The results suggest that the overall stimulus shape rather than processing mode or specific spatial frequency is a primary determinant of hemispheric differences for visual information.
Adult↗
Probability and inter-stimulus interval effects on the P300 from auditory stimuli.
The relationship between target stimulus probability and inter-stimulus interval (ISI) on the P300 (P3) component of the event-related potential was assessed in two experiments. An auditory discrimination paradigm was employed wherein subjects indicated with a finger tap response the occurrence of a randomly presented 2000 Hz target tone embedded in a series of 1000 Hz tones. Experiment 1 presented stimuli with target probabilities of 0.10, 0.30, and 0.50 at ISIs of 1.5 or 3.0 s and produced P3 amplitudes which decreased with increases in target probability and were smaller at the shorter compared to the longer ISI. Experiment 2 presented stimuli with target probabilities of either 0.20, 0.50, or 0.80 at ISIs of 4.0 and 10.0 s and produced P3 amplitudes which were unaffected by either variable. P3 latency demonstrated relatively few changes in either experiment. When taken together with previous findings, the results suggest that inter-stimulus interval affects P3 amplitude by determining the amount of processing resources available during ERP generation.
Acoustic Stimulation↗
Normal variation of P300 in children: age, memory span, and head size.
The P300 (P3) event-related brain potential was elicited in a group of 50 children and young adults (4-20 years). A simple auditory task was employed in which subjects indicated with a finger movement when a randomly occurring target tone (high pitch) was presented in a series of standard (low pitch) tones. The probability of the target tone was varied across conditions at 10%, 30%, or 50% to assess possible developmental changes in P300 amplitude. Memory capacity was assessed with forward and reverse digit spans. Circumference of the head also was measured. P300 latency decreased with age, and P300 amplitude tended to become larger with age. Polynomial regression analyses revealed significant quadratic trends in these relationships, with changes leveling off for older subjects. Digit span and head circumference also were related curvilinearly to P300 values. Multiple regression analysis indicated that changes in age and memory span both predicted significant changes in P300 latency and amplitude. Target stimulus probability generally affected all subjects in a similar fashion, although the strength of the correlational relationships tended to decline with increases in probability. Developmental changes for the N1, P2, and N2 components from the standard stimuli also were obtained. The results are discussed in terms of previous P3 findings for children and their implications for future studies.
Acoustic Stimulation↗
P300 and time of day: circadian rhythms, food intake, and body temperature.
The P300 or P3 component of the event-related brain potential (ERP) was obtained from five groups of 24 young adult subjects, with each group measured at a different time of day (8 a.m., 11 a.m., 2 p.m., 5 p.m., 8 p.m.). An activity-preference questionnaire was used to ensure that an equitable number of morning- and evening-preferring subjects were obtained for each testing time. P3 measures, physiological (body temperature, heart rate, subjective alertness), and cognitive performance (digit span, prose memory, digit symbol) variables were assessed. P3 amplitude and latency were not affected directly by the time of day. However, P3 amplitude was smaller in subjects who had not eaten within 6 hours of testing relative to subjects who had a recent meal, and P3 latency was correlated negatively with body temperature. The findings suggest that although the P3 ERP is not influenced by circadian rhythms, it is related to recency of food intake and physiological factors which change with time of day.
Adolescent↗
P300, probability, and interstimulus interval.
The relationship between target stimulus probability and interstimulus interval on the P300 (P3) component of the event-related potential was assessed in three experiments. In each study an auditory discrimination paradigm was employed wherein subjects indicated with a finger tap response the occurrence of a randomly presented 2000 Hz target tone embedded in a series of 1,000 Hz tones. Target stimuli were presented with a probability of either .20 or .80 in different conditions which were combined factorially with different interstimulus intervals. Experiment 1 presented stimuli at 2.0, 2.5, or 3.0 second intervals; Experiment 2 presented stimuli at 2.0, 3.0, or 4.0 second intervals; Experiment 3 presented stimuli at 4.0, 6.0, or 10.0 second intervals. P3 amplitude was larger for the .20 relative to the .80 target probability conditions for the shorter interstimulus intervals but not for the longer intervals. P3 latency was consistently longer for the .20 relative to the .80 target probability conditions, with generally little effect observed for interstimulus interval changes. The results suggest that interstimulus interval affects component amplitude by determining the amount of processing resources available when the P3 is produced.
Adult↗
Noninvasive trigeminal evoked potentials: normative data and application to neuralgia patients.
A mild electric shock applied to the lower lip was used to elicit reliable evoked potentials from the trigeminal nerve in 20 normal young adults. The wave forms were morphologically similar to those observed with invasive procedures. No substantial differences for either the right or left side of stimulation, recording electrode, or subject sex were obtained for any of the individual potential amplitudes or latencies. The same procedures were applied to 10 patients who had been treated with retrogasserian glycerol injections for trigeminal neuralgia. Trigeminal evoked potentials were elicited in all patients, although the quality of the individual wave forms was more variable than that observed for the normal subjects. Comparison of the treated with the unaffected face side in the patients demonstrated significantly smaller N2-P2 amplitudes and longer N2 latencies for the affected face side. The results suggest that these procedures produce reliable evoked potential measures of trigeminal nerve function noninvasively which can provide an objective index of treatment efficacy.
Adult↗
P300 and probability in children.
The P300 event-related brain potential (ERP) was elicited in three groups of 12 children each, ages 5-9, 10-14, and 15-19 years. A simple auditory task was employed in which subjects indicated with a finger movement when a randomly occurring target tone (high pitch) was presented in a series of standard (low pitch) tones. The probability of the target tone was varied across conditions at 0.10, 0.30, or 0.50 to determine if P300 amplitude would respond similarly across age groups. Immediate memory capacity was measured with forward and reverse digit spans. P300 amplitude increased with decreases in target stimulus probability for each age group and also tended to become larger with age. P300 latency decreased in the same fashion across probability levels as age increased. Digit span demonstrated the usual increase with age. The results suggest that cognitive development is indexed by decreases in P300 latency, and that P300 amplitude changes from the probability of the target stimulus are similar across age groups. The implications for the theoretical interpretation of the P300 and application of ERPs for evaluating cognitive development are discussed.
Adolescent↗