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Biomedical subjects

K L Lange

Publications and source records attributed to K L Lange.

6 recordsLinked to original sources
PubMed1997

A dissociation between perceptual explicit and implicit memory processes.

Patient M.S., who underwent right-occipital lobe resection to treat intractable epilepsy, has intact recall and recognition memory for words, but impaired repetition priming in word identification and visual stem-completion tasks. This mirror dissociation to amnesia suggests that explicit recognition and visuoperceptual repetition priming are mediated by distinct neural systems. In prior studies, however, M.S.' recognition memory was tested only with tasks that drew upon his intact verbal knowledge. The present study examined M.S.' recognition memory for nonverbal perceptual information, namely, the modality and font of word presentation and line patterns. M.S.' recognition memory was intact, providing further evidence that perceptual explicit and implicit memory processes are subserved by functionally and neurally independent memory systems.

Adult↗
PubMed1997

Word-stem completion priming for perceptually and conceptually encoded words in patients with Alzheimer's disease.

This study examined whether the frequently reported word-stem completion priming deficit of Alzheimer's disease (AD) patients could be characterized as either a semantic encoding deficit or a conceptual priming deficit. AD patients and normal elderly control subjects studied words in two conditions: (1) reading visually presented words aloud, which maximizes perceptual encoding of seen words, and (2) generating words aloud from definitions, which maximizes conceptual encoding of words not seen but retrieved on the basis of semantic context. Recognition accuracy was greater for words that were generated at study, and word-stem completion priming was greater for words that were read at study. For the AD patients, recognition accuracy was impaired and word-stem completion priming was intact for words encoded in both conditions. The findings are discussed in terms of discrepant results about word-stem completion priming in AD.

Aged↗
PubMed1997

Sources of priming in text rereading: intact implicit memory for new associations in older adults and in patients with Alzheimer's disease.

The contributions of text meaning, new between-word associations, and single-word repetition to priming in text rereading in younger and older adults, and in patients with Alzheimer's disease. (AD), were assessed in Experiment 1. Explicit recognition memory for text was also assessed. Equivalent single-word and between-word priming was observed for all groups, even though patients with AD showed impaired explicit memory for individual words in the text. The contribution of generalized reading task skill to priming in meaningless text rereading in younger adults was assessed in Experiment 2. Generalized reading task skill was also found to contribute to priming. These results reveal 3 mechanisms of priming: new between-word associations for meaningful and meaningless text, individual word repetition for meaningless text, and general task or skill factors for meaningless text. All priming mechanisms appear to be intact in older adults and in patients with AD.

Adult↗
PubMed1980

A three-allele model for heterogeneity of juvenile onset insulin-dependent diabetes.

A three-allele model is presented for the inheritance of 'juvenile' insulin-dependent diabetes mellitus (IDDM). The model postulates a susceptibility locus S tightly linked to the HLA complex. The model incorporates relative-risk and HLA-association data from the literature which suggest genetic heterogeneity within IDDM, together with population prevalence, twin and sib concordance rates, and distortions in HLA-haplotype concordance values for affected sib pairs. The model appears to provide a reasonable fit to existing data. It predicts low penetrances for some, but not all, genotypes and a strong association between HLA B8 and one of the S alleles. The model makes additional specific predictions about how different forms of IDDM are distributed in sporadic and familial cases. These predictions can be tested in future genetic-epidemiologic studies.

Alleles↗
PubMed1980

Second-order approximations of ascertainment probabilities.

A second-order correction is derived for the usual first-order order approximation to the probability of ascertaining a pedigree. Both the first- and second-order approximations are compared to the exact ascertainment probability for selected examples of monogenic and polygenic traits. The second-order approximation is shown to be accurate within 10% when the individual ascertainment probability is less than 0.2, for most cases examined. In all cases, the first- and second-order approximations provide upper and lower bounds, respectively, for the exact ascertainment probability.

Humans↗