PMID- 9299070
OWN - NLM
STAT- MEDLINE
DCOM- 19971223
LR  - 20071114
IS  - 0093-934X (Print)
IS  - 0093-934X (Linking)
VI  - 59
IP  - 3
DP  - 1997 Oct 1
TI  - Speed of lexical activation in nonfluent Broca's aphasia and fluent Wernicke's 
      aphasia.
PG  - 391-411
AB  - Rapid, automatic access to lexical/semantic knowledge is critical in supporting 
      the tight temporal constraints of on-line sentence comprehension. Based on 
      findings of "abnormal" lexical priming in nonfluent aphasics, the question of 
      disrupted automatic lexical activation has been the focus of many recent efforts 
      to understand their impaired sentence comprehension capabilities. The picture 
      that emerges from this literature is, however, unclear. Nonfluent Broca's aphasic 
      patients show inconsistent, not absent, lexical priming, and there is little 
      consensus about the conditions under which they do and do not prime. The most 
      parsimonious explanation for the variable findings from priming studies to date 
      is that the primary disturbance in Broca's lexical activation has something to do 
      with speed of activation. Broca's aphasic patients prime when sufficient time is 
      allowed for activation to spread among associates. To examine this "slowed 
      activation" hypothesis, the time course of lexical activation was examined using 
      a list priming paradigm. Temporal delays between successive words ranged from 300 
      to 2100 msec. One nonfluent Broca's aphasic patient and one fluent Wernicke's 
      patient were tested. Both patients displayed abnormal priming patterns, though of 
      different sorts. In contrast to elderly subjects, who prime at relatively short 
      interstimulus intervals (ISIs) beginning at 500 msec, the Broca's aphasic subject 
      showed reliable automatic priming but only at a long ISI of 1500 msec. That is, 
      this subject retained the ability to access lexical information automatically if 
      allowed sufficient time to do so, a finding that may help explain disrupted 
      comprehension of normally rapid conversational speech. The Wernicke's aphasic 
      subject, in contrast, showed normally rapid initial activation but continued to 
      show priming over an abnormally long range of delays, from 300 msec through 1100 
      msec. This protracted priming suggests failure to dampen activation and might 
      explain the semantic confusion exhibited by fluent Wernicke's patients.
FAU - Prather, P A
AU  - Prather PA
AD  - Boston Department of Veterans Affairs Medical Center, MA 02130, USA.
FAU - Zurif, E
AU  - Zurif E
FAU - Love, T
AU  - Love T
FAU - Brownell, H
AU  - Brownell H
LA  - eng
GR  - AG10496/AG/NIA NIH HHS/United States
GR  - DCD0081/DC/NIDCD NIH HHS/United States
GR  - NS27894/NS/NINDS NIH HHS/United States
PT  - Case Reports
PT  - Journal Article
PT  - Research Support, U.S. Gov't, Non-P.H.S.
PT  - Research Support, U.S. Gov't, P.H.S.
PL  - Netherlands
TA  - Brain Lang
JT  - Brain and language
JID - 7506220
SB  - IM
MH  - Aphasia, Broca/*physiopathology
MH  - Aphasia, Wernicke/*physiopathology
MH  - Frontal Lobe/*physiopathology
MH  - Humans
MH  - Male
MH  - Middle Aged
MH  - Reaction Time
MH  - Temporal Lobe/*physiopathology
MH  - Time Factors
MH  - *Vocabulary
EDAT- 1997/09/23 00:00
MHDA- 1997/09/23 00:01
CRDT- 1997/09/23 00:00
PHST- 1997/09/23 00:00 [pubmed]
PHST- 1997/09/23 00:01 [medline]
PHST- 1997/09/23 00:00 [entrez]
AID - S0093-934X(97)91751-X [pii]
AID - 10.1006/brln.1997.1751 [doi]
PST - ppublish
SO  - Brain Lang. 1997 Oct 1;59(3):391-411. doi: 10.1006/brln.1997.1751.