Biomedical subjects

Hiram Brownell

Publications and source records attributed to Hiram Brownell.

5 recordsLinked to original sources

PubMed2006

Inference of beliefs and emotions in patients with Alzheimer's disease.

The present study compared 20 patients with mild to moderate Alzheimer's disease with 20 older controls (ages 69-94 years) on their ability to make inferences about emotions and beliefs in others. Six tasks tested their ability to make 1st-order and 2nd-order inferences as well as to offer explanations and moral evaluations of human action by appeal to emotions and beliefs. Results showed that the ability to infer emotions and beliefs in 1st-order tasks remains largely intact in patients with mild to moderate Alzheimer's. Patients were able to use mental states in the prediction, explanation, and moral evaluation of behavior. Impairment on 2nd-order tasks involving inference of mental states was equivalent to impairment on control tasks, suggesting that patients' difficulty is secondary to their cognitive impairments. ((c) 2006 APA, all rights reserved).

Aged↗

PubMed2006

Theory of mind and the right cerebral hemisphere: refining the scope of impairment.

The neuropsychological and functional characterisation of mental state attribution ("theory of mind" (ToM)) has been the focus of several recent studies. The literature contains opposing views on the functional specificity of ToM and on the neuroanatomical structures most relevant to ToM. Studies with brain-lesioned patients have consistently found ToM deficits associated with unilateral right hemisphere damage (RHD). Also, functional imaging performed with non-brain-injured adults implicates several specific neural regions, many of which are located in the right hemisphere. The present study examined the separation of ToM impairment from other deficits associated with brain injury. We tested 11 patients with unilateral right hemisphere damage (RHD) and 20 normal controls (NC) on a humour rating task, an emotion rating task, a graded (first-order, second-order) ToM task with non-mentalistic control questions, and two ancillary measures: (1) Trails A and B, in order to assess overall level of impairment and set-shifting abilities associated with executive function, and (2) a homograph reading task to assess central coherence skills. Our findings indicate that RHD can result in a functionally specific deficit in attributing intentional states, particularly those involving second-order attributions. Performance on ToM questions was not reliably related to measures of cognitive impairment; however, performance on non-ToM control questions was reliably predicted by Trails A and B. We also discuss individual RHD patients' performance with attention to lesion locus. Our findings suggest that damage to the areas noted as specialised in neuroimaging studies may not affect ToM performance, and underscore the necessity of combining lesion and imaging studies in determining functional-anatomical relations.

Adult↗

PubMed2005

Variable solutions to the same problem: aberrant practice effects in object naming by three aphasic patients.

Although deficits in confrontation naming are a common consequence of damage to the language areas of the left cerebral hemisphere, some patients with aphasia show relatively good naming ability. We measured effects of repeated practice on naming latencies for a set of pictured objects by three aphasic patients with near-normal naming ability and by neurologically intact young and older adults. While the non-injured participants showed a systematic reduction in overall mean latencies and reduced trial-to-trial latency variability, the aphasic patients did not. Examination of the latency distributions suggests that successful naming by aphasic patients may come about by different underlying operations.

Adolescent↗

PubMed2005

Effects of syntactic features on sentence-picture matching in Broca's aphasics: a reply to Drai and Grodzinksy (2005).

We reanalyzed the data in , considering individual patients' responses to different sentence types to be non-independent events. The analyses revealed effects of two of the three factors identified by Drai and Grodzinsky--constituent movement and passive mood. The result is inconsistent with the trace deletion hypothesis; we conclude that features of syntactic structure other than constituent movement are relevant to understanding performance variation in patients with Broca's aphasia.

Aphasia, Broca↗

PubMed2004

Inference of mental states in patients with Alzheimer's disease.

INTRODUCTION: The ability to determine what someone thinks or knows often requires an individual to infer the mental state of another person, an ability typically referred to as one's "theory of mind". The present study tests this ability in patients with mild-to-moderate Alzheimer's disease (AD). METHODS: Three theory of mind tests and three standardised neuropsychological tests were presented to a group of patients with AD (n = 25) and a group of healthy elderly controls (n = 15). RESULTS: On the first two theory of mind tasks, the performance of the AD patients was nearly perfect and did not differ from that of the controls: AD patients showed no difficulties in either attributing a false belief to another person, or in recognising their own previous false beliefs. On the third theory of mind task, where the key information was embedded in a story narrative, AD patients per formed significantly worse than controls. However, their performance on this task was similar to the control condition, which used a similar story but which did not involve beliefs. CONCLUSIONS: These results, as well as those involving correlations between the neuropsychological tests and performance on the third task, suggest that the AD patients' difficulty may be secondary to their cognitive impairments, rather than a primary impairment in theory of mind.

Journal Article↗