James R. Tweedy

Right hemisphere specialization for the identification of emotional words and sentences; evidence from stroke patients

This study examines the contribution of the lexical/verbal channel to emotional processing in 16 right brain-damaged (RBD), 16 left brain-damaged (LBD) and 16 normal control (NC) right-handed adults. Emotional lexical perception tasks were developed; analogous nonemotional tasks were created to control for cognitive and linguistic factors. The three subject groups were matched for gender, age and education. The brain-damaged groups were similar with respect to cerebrovascular etiology, months post-onset, sensory-motor status and lesion location. Parallel emotional and nonemotional tasks included word identification, sentence identification and word discrimination. For both word tasks, RBDs were significantly more impaired than LBDs and NCs in the emotional condition. For all three tasks, RBDs showed a significantly greater performance discrepancy between emotional and nonemotional conditions than did LBDs or NCs. Results were not affected by the valence (i.e. positive/negative) of the stimuli. These findings suggest a dominant role for the right hemisphere in the perception of lexically-based emotional stimuli.

Significance of cortical disinhibition signs

Several clinical signs traditionally associated with dementia were examined in a series of 103 patients referred to a dementia clinic. The snout and grasp reflexes were significantly correlated with impaired performance on cognitive tests, but not accentuated jaw-jerk, glabellar reflex, paratonia, suck, root, or palmomental reflexes. In general, the signs were more strongly correlated with CT evidence of ventricular dilation than with cortical atrophy. They seem to be related to supranuclear motor system dysfunction, and cannot be considered clinical markers of dementia.

The effect of semantic relations on the memory deficit associated with parkinson's disease

Analysis of a series of verbal memory experiments reveals a systematic performance deficit in subjects with Parkinsons disease, relative to matched normal and right-hemisphere stroke controls, in both recall and recognition tasks. Parkinson patients benefit less from semantic recall cues; they find semantically mediated synonym detections particularly difficult; and they show reduced benefits from the introduction of semantically novel material in a recall task. Their recall is as well organized semantically as that of normal controls, but reduced in amount. Recognition deficits arise principally from increases in false positive responses.

Interrelationships among subject variables believed to predict cerebral organization

Abstract A variety of subject variables have been proposed as having predictive value for determining cerebral organization. Subject variables proposed as likely candidates include strength of handedness, familial sinistrality, writing posture, and sex. The present study examined the interrelationships among these variables by means of a questionnaire given to 847 undergraduates.

Neuropsychological aspects of Parkinson's disease.

The neuropsychological effects of Parkinsons disease have gained wide recognition in recent literature. Effects have been documented in almost all areas of cognitive functioning, including general intellectual functioning, visual-spatial functioning, executive functions, attention and memory functions, language functions, and affective processes. Visual-spatial functions, memory functions, and executive functions have received particular interest. This review of the literature is an attempt to tie together the large number of studies in these cognitive areas and to present a suggestion for a comprehensive neuropsychological battery tailored to the patient with Parkinsons disease. Throughout the review, factors relevant to Parkinsons disease, e.g., dementia, motor symptoms, and hemiparkinsonism, are considered.

Cerebral blood flow in severity‐matched Alzheirner and multi‐infarct patients

Cerebral blood flow was studied in patients meeting research criteria for either Alzheimers disease or multi-infarct dementia, matched for age and severity of dementia. In both groups, mean flow was less than in age-matched normal controls, but the Alzheimer patients also had significantly lower mean flow than the multi-infarct group. This result helps resolve discrepancies found in studies with inadequate control for severity. Either global flow or regional left parietal flow could be used to discriminate between these dementia categories with 87% accuracy.

Verbal Pragmatics Following Unilateral Stroke: Emotional Content and Valence

Verbal pragmatic aspects of discourse production were examined in 16 right brain-damaged (RBD), 16 left brain-damaged (LBD), and 16 normal control right-handed adults. The facilitation effect of emotional content, valence hypothesis, and relationship between pragmatics and emotion were evaluated. Participants produced monologues while recollecting emotional and nonemotional experiences. Transcribed monologues were rated for appropriateness on 6 pragmatic features: conciseness, lexical selection, quantity, relevancy, specificity, and topic maintenance. Overall, brain-damaged groups were rated as significantly less appropriate than normals. Consistent with the facilitation effect, emotional content enhanced pragmatic performance of LBD aphasic participants yet suppressed performance of RBD participants. Contrary to the valence hypothesis, RBD participants were more impaired for positive emotions and LBD participants for negative emotions. Pragmatic appropriateness was not strongly correlated with a measure of emotional intensity.

Set-shifting and spatial orientation in patients with Parkinson's disease.

Individuals with Parkinsons disease were compared to normal control subjects on a series of widely used neuropsychological measures. The two groups were matched for gender, handedness, age, education, and occupation. The neuropsychological tests were chosen to measure two specific functions: (a) spatial orientation (i.e., measures of personal orientation, extrapersonal orientation, right/left orientation, and mental rotation), and (b) the ability to shift mental set (e.g., generating responses from alternating categories). The tests chosen to measure spatial orientation had no set-shifting component, and the tests chosen to measure set-shifting had no spatial orientation component. Multivariate statistical analyses revealed a significant difference between the subjects with Parkinsons disease and the control subjects on the measures of set-shifting ability. In contrast, no significant difference between the groups was observed on the measures of spatial orientation. These results are discussed in terms of the current speculation in the literature regarding the relationship between set-shifting deficits and a disruption of dopaminergic fibers to the prefrontal cortex in Parkinsons disease.

Underdiagnosis of Cognitive Impairment in a Rehabilitation Setting

Of 100 patients consecutively admitted to a rehabilitation hospital, 25 were cognitively impaired. On two brief tests of intellectual function, they scored below the criteria selected by the originators of those tests for clinically significant mental impairment. Nineteen of the 25 had vascular disease of the heart, brain, or peripheral vessels; two had cardiac valvular disease; three had head trauma; and one was mentally retarded. Mental impairment appears to be relatively common among the hospitalized elderly who do not carry the primary diagnosis of “dementia” or “organic brain syndrome.” It appears to be particularly common among those with cardiovascular disease, even without frank stroke. Brief mental status examinations should be part of the routine evaluation of such patients.

Performance asymmetries in dichotic listening: The role of structural and attentional mechanisms

Abstract The present study was designed to test a prediction derived from the attentional model of the ear asymmetry phenomenon observed in dichotic listening. Pairs of consonant-vowel syllables were presented through headphones and through loudspeakers to three commissurotomy and 20 neurologically normal subjects. Proponents of the attentional model have suggested that both groups of subjects should show an asymmetry in favor of the stimulus delivered from the right that is independent of whether headphones or loudspeakers are used. Results showed that the right side advantage obtained in the headphone modality decreased but did not disappear for both subject groups when stimuli were presented through loudspeakers. Implications for the role of structural and attentional mechanisms in dichotic listening performance are considered.