Recognition by familiarity is preserved in Parkinson's without dementia and Lewy-Body disease.
OBJECTIVE
The retrieval deficit hypothesis states that the lack of deficit in recognition often observed in patients with Parkinson's disease is because of the low retrieval requirements of the task, given that these patients have retrieval and not encoding deficits. To test this hypothesis we investigated recognition memory by familiarity in Parkinson's patients and in patients with Lewy Bodies disease and Parkinson with dementia.


METHODS
We analyzed to what extent the experimental groups were able to recognize by familiarity in a typical yes/no recognition memory task. The experimental groups were patients with early nondemented Parkinson's disease, advanced nondemented Parkinson's disease, demented Parkinson's patients, and patients with dementia with Lewy Bodies. We compared their performance with a group of young and another group of old healthy participants. The estimation of familiarity was made by analyzing recognition of word targets and distractors consisting of combinations of different letters in comparison with a condition in which targets and distractors were composed of similar letters, even though subjects were unaware of the independent variable.


RESULTS
The results indicate that familiarity was used at the same level by controls, patients with early Parkinson's disease and patients with dementia with Lewy Bodies. Although late Parkinson patients also used familiarity, its effect was only marginally significant. Patients with Parkinson's disease and dementia were not capable of using familiarity in recognition memory.


CONCLUSIONS
Our results support the retrieval deficit hypothesis as Parkinson's patients without dementia show no deficit in a situation in which the retrieval requirements are minimal.
Algarabel
Salvador
S
Methodology Department, University of Valencia, Blasco Ibanyez, 21, 46010 Valencia, Spain. Salvador.Algarabel@uv.es
Rodríguez
Lucía-Azahara
LA
Escudero
Joaquín
J
Fuentes
Manuel
M
Peset
Vicente
V
Pitarque
Alfonso
A
Cómbita
Lina-Marcela
LM
Mazón
Jose F
JF
D000368:Aged; D000704:Analysis of Variance; D016022:Case-Control Studies; D003704:Dementia / Q000150:complications / Q000503:physiopathology / Q000523:psychology*; D006801:Humans; D020961:Lewy Body Disease / Q000150:complications / Q000503:physiopathology / Q000523:psychology*; D016555:Matched-Pair Analysis; D011939:Mental Recall / Q000502:physiology*; D010300:Parkinson Disease / Q000150:complications / Q000503:physiopathology / Q000523:psychology*; D021641:Recognition, Psychology / Q000502:physiology*; D012016:Reference Values