Biomedical subjects
B D MacQueen
Publications and source records attributed to B D MacQueen.
Disturbances of mental image processing in post-stroke patients with left and right hemisphere damage.
BACKGROUND: The purpose of this article is to point out significant differences in how mental images are processed by post-stroke patients with left and right hemisphere damage. The issues involved are of theoretical importance because of the light shed on the modularity of cerebral functions, especially the imagination, and of clinical importance due to the better understanding of the underlying pathomechanism. MATERIAL AND METHODS: The research involved 82 right-handed patients with a lesion in the left hemisphere (Group L), 82 right-handed patients with a lesion in the right hemisphere (Group R), and, as a control group, 82 patients with musculo-skeletal disorders not affecting the central nervous system (Group C), matched by age and sex. Image processing of complex notions was examined by using selected items from the Simple Neurolinguistic Test. RESULTS: In the control group, the majority of the patients responded to most of the prompts with polymodal associations of various types. In Group L, responses were dominated by isolated elements of the complex situation, while in Group R the associations were mostly verbal (lexical) and highly restricted in scope. CONCLUSIONS: The results indicate that the loss of LH functions interferes with the ability to assemble pieces of polymodal image information into sensible strings, while the loss of RH functions leaves strings to which little information is attached.
Neuropsychological features of rapidly progressive dementia in a patient with an atypical presentation of Creutzfeldt-Jakob Disease.
BACKGROUND: Creutzfeldt-Jakob Disease (CJD) is a degenerative disease of the brain, characterized by rapid and irreversible decline, with dementia, ataxia, myoclonus, and other neurological and neurobehavioral disorders associated with rapidly progressive spongiform encephalopathy. The mode of transmission and basic pathomechanism remain unclear. The clinical picture of CJD is highly diverse, producing a number of variants. MATERIAL AND METHODS: The patient to be described is a 68-year-old Polish female, JR, clinically diagnosed with CJD. The article presents the case history in detail, with particular emphasis on neuropsychological testing, which was initiated when the patient was still lucid and capable of cooperation. The first presenting symptom was agraphia, followed by hemianopsia and other vision disorders, culminating in visual hallucinations. As the progress of the disease accelerated there was rapidly progressive dementia, aphasia developing to organic mutism, myoclonus, hyperkinesia, ultimately loss of all verbal contact or voluntary movement. RESULTS: JR's neuropsychological parameters declined in a period of less than 3 months from near normal to levels characteristic of severe dementia. CONCLUSIONS: The clinical picture here presented is consistent with that of the Heidenhain variant of CJD, with spongiform encephalopathy beginning in the right occipital lobe. Several features of the case remain atypical, however, including the absence of the most common genetic mutation and the patient's long survival after onset.
[Pathomechanism and clinical presentation of neurobehavioral disturbances in a patient with MELAS syndrome].
The authors present the results of a longitudinal study of the neurobehavioral disturbances seen in K.S., a 22-year-old female patient with a mitochondrial cytopathy (MELAS) caused by the novel mutation C8293T. K.S. became ill in 1994 at the age of 16. She was referred for diagnosis to several different clinics. Four years after onset, the clinical diagnosis was established in the Department of Medical Rehabilitation at the Cracow Rehabilitation Center; the diagnosis was not confirmed until six years after onset, following the discovery of the mutation in the patient's mtDNA at Columbia University. Since 1996 the patient has presented with progressive dementia and periodic stroke-like episodes that produced fluctuating neurological symptoms. The essential pathomechanism of the neurobehavioral disturbances consists in the fragmentation of complex cerebral processes into their constituent elements; individual functions are frequently correctly executed on a lower level of cerebral organization, but the patient is unable to combine them into a sensible whole. The authors discuss the theoretical and clinical significance of the results presented here.