CAC 2000 poster: OTV

1
Robust Word-Picture Priming in Aging Evidence
From ERPs and Application to Dementia
Natalie A. Phillips1,2, Sarah Auchterlonie1,
Howard Chertkow2
1Psychology/Centre for Research in Human
Development, Concordia University, Montréal,
Québec, Canada 2Lady Davis Institute/Neurology,
Jewish General Hospital, Montréal, Québec, Canada

• Introduction
• The presence of age differences in semantic
  priming remains controversial. There is evidence
  both for equivalent semantic priming in young and
  older adults (Kellas et al., 1995) and also
  evidence for greater priming effects in older
  adults (Laver Burke, 1993).
• Few studies have examined word-picture priming
  in aging. Bowles (1994) found equivalent priming
  in young and old adults in the onset of
  facilitation and inhibition by primes.
• We examined event-related brain potential (ERP)
  measures of priming in young and older adults for
  future application to patients with Dementia of
  the Alzheimer Type (DAT).
• N400 component was examined because its
  amplitude varies inversely with semantic priming
  unprimed words elicit large N400s while primed
  words elicit small N400 activity (Kutas
  Hillyard, 1980).

Figure 4. The grand average waveforms of the 3
priming conditions for each group.
Figure 1. Example of the 3 priming conditions.
Figure 5. The grand average waveforms comparing
Elderly vs. DAT for each of the 3 conditions.
Figure 2. Time course of stimulus presentation.

• Discussion
• Significant N400 effect indicates young and
  elderly adults benefit from identity and related
  word primes when processing pictures.
• Results are important because they indicate
  age-invariant semantic priming for word-picture
  pairs.
• Results provide a useful baseline against which
  semantic deficits in DAT may be evaluated.
• Preliminary results suggest a reduction in
  semantic priming in patients with DAT. However,
  this result must be confirmed in a larger patient
  sample.
• We are currently examining word-picture priming
  in Alzheimers disease, and examining ERP priming
  as a function of semantic memory performance on
  an item-by-item basis.

• Results
• Analyses were planned comparisons for Young vs.
  Elderly and Elderly vs. DAT.
• Within each group, differences between
  conditions were tested.
• The main results for each analysis are presented
  below.
• Y vs. E F (1,18) .87, n.s.
• E vs. DAT F (1,12) .33, n.s.
• Young F (2,18) 9.03, p .003, U gt I R
• Elderly F (2,18) 6.05, p .02, U gt I R
• DAT F (2,6) 3.30, n.s.

Participants

• Stimuli Procedure
• Stimuli were 106 line drawings and 318 words.
• Pictures were presented under 3 different
  priming conditions identity prime, related
  prime, and unrelated prime, see Fig. 1.
• A word prime was presented followed by a picture
  target. ERP recording was time-locked to the
  presentation of the picture (see Fig.2 for time
  course of stimulus presentation).
• Ss were told to attend to the word-picture
  pairs.
• To ensure their attention, Ss were asked
  approximately every 20 trials whether or not a
  picture or word had been shown.

References
Bowles, N.L. (1994). Age and rate activation in
semantic memory. Psychology and Aging, 9,
414-429. Kellas, G., Paul, S.T., Vu, H.
(1995). In P.A. Allen, T.R. Bashore (Eds.) Age
Differences in Word and Language Processing.
(pp.143-170). Amsterdam Elselvier
Science. Kutas, M., Hillyard, S. (1980).
Reading senseless sentences Brain potentials
reflect semantic anomaly. Science, 225,
1168-1170. Laver, G.D., Burke, D.M. (1993).
Why do semantic priming effects increase in old
age? A meta-analysis. Psychology and Aging, 8,
34-43.
Figure 3. Voltage maps of the N400 effect
(Unrelated - Identity). This shows robust
priming effects in Young and Elderly and
reduced priming in DATs.
Funded by FCAR Nouveaux Chercheurs. We would like
to acknowledge Shelley Solomon for DAT patient
recruitment.