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B T Volpe

Publications and source records attributed to B T Volpe.

At least 73 records · Page 4Linked to original sources
PubMed1988

More on recognition and recall in amnesics.

Hirst et al. (1986) reported that amnesic forced-choice recognition was relatively preserved when compared with amnesic recall. They equated normal recognition and amnesic recognition by extending exposure time for the amnesics and then comparing amnesic recall and normal recall. Amnesic recall was worse than normal recall, despite equated recognition. We conducted two experiments to extend that result. Experiment 1 established that the findings of Hirst et al. are not paradigm specific and hold when amnesic recognition and normal recognition are equated by increasing the retention interval for normals. In Experiment 2 we further established the generality of the result by examining yes-no recognition. Findings further specify the selective nature of the direct memory deficit in amnesics.

Amnesia↗
PubMed1988

Impaired syntactic comprehension and production in Broca's aphasia: CT lesion localization and recovery patterns.

Three of 50 patients with left hemisphere stroke manifested Broca's aphasia associated with deficits in syntactic processing. CT demonstrated anterior infarcts in two patients and a posterior infarct in the third. Two years later, all three patients showed improved syntactic production, but only the patient with the posterior lesion performed significantly above change on a sentence comprehension test requiring syntactic manipulations in the absence of semantic constraints. Prospective investigations combining psycholinguistic analyses and brain imaging techniques may provide empiric data relevant to neurologic models of language and ultimately may contribute to patient prognostication and rehabilitation.

Aged↗
PubMed1987

Retention of reference memory following ischemic hippocampal damage.

Retention of reference memory was evaluated in an animal model of cerebral ischemia. Rats were trained for 70 daily trials on an 8-arm radial maze with 5 arms baited, subjected to 30 minutes of forebrain ischemia, allowed to recover for 30 days, and then tested for an additional 50 trials. Post ischemic (PI) rats demonstrated normal retention of reference memory (p less than 0.05). Working memory was significantly impaired postoperatively (p less than 0.05). Morphologic analysis showed that PI rats had primary loss of pyramidal neurons in the CA1 region of hippocampus.

Animals↗
PubMed1986

Reference and working memory of rats following hippocampal damage induced by transient forebrain ischemia.

Acquisition of reference and working memory was evaluated in an animal model of cerebral ischemia. Rats were subjected to 30 minutes of transient forebrain ischemia, allowed to recover, and then tested for 95 trials on an 8-arm maze with 5 arms baited. During the 95 trials post ischemic (PI) rats made significantly more working and reference errors than controls (p less than 0.05). However, an analysis of the last 20 trials (75-95) showed that while PI rats and control rats had comparable reference memory (p greater than 0.8). PI rats tended to have a persistent working memory deficit compared to controls (p less than 0.06). Subsequent morphologic analysis showed that PI rats had almost complete loss of pyramidal neurons in the anterior CA1 region of the hippocampus, moderate to severe loss in mid-dorsal posterior hippocampus, and less damage to the dorsolateral striatum. These results suggest that the PI animal is a reasonable model for the permanent behavioral impairment and pathologic damage found in some human survivors of cardiac arrest.

Animals↗
PubMed1986

Components of visual attention. Alterations in response pattern to visual stimuli following parietal lobe infarction.

The contribution of attentional factors per se in response to visual stimuli was studied in patients with unilateral lesions of the left or right cerebral hemispheres. Subjects were required to respond to visual targets that were presented tachistoscopically, and were preceded by spatial cues that served to manipulate the spatial locus of attention. On 'valid' cue trials, the cue directed attention to the target's spatial coordinates; on 'invalid' cue trials, the cue misdirected attention. It was determined that damage to either the left or right hemisphere results in a general slowing of reaction times to visual stimuli irrespective of where such stimuli appear, and that patients with right parietal lesions are further impaired at shifting attention within the left visual field.

Adult↗
PubMed1986

Further characterization of patients with amnesia after cardiac arrest: preserved recognition memory.

We observed that patients with amnesia after cardiac arrest had preserved recognition memory despite profound loss of recall memory. In the present study, rate of forgetting was measured in six amnesic subjects for both recall and recognition memory of verbal material. The data show that recall decayed significantly faster for the amnesic subjects than for controls, whereas the rate of forgetting for recognition memory was comparable in both groups. Dissociation between recall and recognition performance is a feature of the amnesic syndrome after cardiac arrest.

Adult↗
PubMed1986

Recognition and recall in amnesics.

Although there is considerable agreement that performance in direct memory tasks (e.g., recall, recognition) is more disrupted by amnesia than performance in indirect memory tasks (e.g., mirror reading, word completion), one may be able to further circumscribe the deficit within the domain of direct memory tasks. The present article explores whether recall is disproportionately disrupted by amnesia compared to recognition. If amnesia affects memory uniformly across different direct memory measures, recall of normal controls should not differ from the recall of amnesics when recognition scores of these two groups are equated. On the other hand, if recall is disproportionately disrupted, normal recall should be superior to amnesic recall even when recognition is equated. The present study equated amnesic recognition with that of controls by providing amnesics with 8 s of study time and normal subjects with 0.5 s. Amnesics with Korsakoff's syndrome, amnesics with other etiologies, and appropriate controls were examined. Normal recall was superior to amnesic recall even when no differences were found in recognition. The results further specify the selective nature of amnesia.

Alcohol Amnestic Disorder↗
PubMed1985

Semantic activation in patients with Parkinson's disease.

Fifteen patients with Parkinson's Disease and fifteen age matched control subjects performed a reaction time task which permitted the separation of gross motoric slowing from the slowing of an internal mental process. The Parkinsonian subjects were slower overall than controls, indicating the expected slowing in their gross motoric responses. However, there was no difference between the Parkinsonian subjects and the control subjects in the speed of internal mental processing. These results suggest that PD may not impair an automatic process like access to semantic memory.

Aged↗
PubMed1985

Delayed pneumonia after aspiration of 'dashboard' fragment.

We report a patient who aspirated a fragment of plastic/foam rubber after a motor vehicle accident. Pneumonia with granuloma formation became apparent only 4 months after the accident. After removal of the fragment, revealed in the left lower lobe by fiberoptic bronchoscopy, the patient recovered.

Accidents, Traffic↗
PubMed1985

Dementia with bilateral medial temporal lobe ischemia.

Neuropathologic examination of two patients with dementia showed chronic bilateral medial temporal lobe ischemic damage that included the hippocampus (particularly the CA-1 region), subiculum, and amygdala. Both patients had several myocardial infarctions, and the relatively circumscribed cerebral injury may have resulted from one or more episodes of global hypoxic ischemia. Focal hippocampal injury has been associated with amnesia. The additional damage to medial temporal lobe structures may have caused the dementia.

Aged↗
PubMed1984

Encoding of spatial relations with amnesia.

Incidental and intentional learning of spatial location was studied in amnesics and normals. It was found that spatial encoding of amnesics improved with instruction whereas the spatial encoding of normal adults did not. The finding suggests that spatial encoding in amnesics may be qualitatively different from that of normal adults.

Adult↗
PubMed1984

Failure of preference formation in amnesia.

Information about the frequency of a stimulus influences the formation of preference judgments in normal subjects. In contrast, results show that patients who have amnesic syndromes have difficulty generating preferences on the basis of frequency information. It is unlikely that difficulty in forming preferences is caused merely by poor mnemonic capacity. Patients with amnesia may lack the affective response to stimuli that may be important for remembering events.

Adult↗
PubMed1983

The characterization of an amnesic syndrome following hypoxic ischemic injury.

We used clinical analysis and criteria derived from the experimental studies of classic amnesic syndromes to characterize the amnesia that follows hypoxic ischemic brain injury from cardiac or respiratory arrest. The results show that patients with hypoxic ischemic amnesia have several neuropsychological features in common with other amnesics, including intact short-term memory, severely depressed free recall, and less depressed recognition of visual and verbal material. Unlike amnesics with alcoholic Korsakoff's syndrome, they are oriented and do not confabulate. Hypoxic ischemic brain injury is a common hospital occurrence, and a study of the characteristics of the amnesia that can occur after such injury should enlarge our understanding of the amnesic syndromes.

Adult↗
PubMed1983

Design of steady-state positron emission tomography protocols for neurobehavioral studies: CO15O and 19Ne.

Although the [18F]-2-fluoro-2-deoxyglucose positron emission tomographic technique for measuring regional glucose metabolic rate has been successfully employed for neurobehavioral studies, the long (greater than 30 min) equilibration time required may complicate the interpretation of experimental results. Positron emission tomography neurobehavioral protocols employing the continuous inhalation of CO15O and 19Ne were developed for measuring regional cerebral blood flow during multiple control and stimulation periods. Timing, lung absorbed dose, statistical accuracy, and resolution were considered. Studies with 19Ne require shorter equilibration and stimulation times than do CO15O studies but entail higher absorbed doses and yield poorer imaging statistics.

Absorption↗
PubMed1983

Amnesia following the rupture and repair of an anterior communicating artery aneurysm.

Clinical analysis and neuropsychological criteria derived from experimental studies of human amnesic syndromes, particularly the alcoholic Korsakoff's syndrome, have been used to characterise an unusual form of amnesia that occurred in two patients after rupture of an anterior communication cerebral artery aneurysm. Intraoperative observation and multiple CT scans did not reveal focal brain damage. Arteriography showed that both patients had arterial vasospasm. The amnesia has persisted over three years since the surgery. Study of the characteristics of their amnesia showed several features in common with other amnesic syndromes, including severely depressed free recall, and less depressed recognition of visual and verbal material. Chronic amnesic syndromes with characteristics of classical amnesic syndromes occur infrequently after rupture and repair of intracranial aneurysms, and, if not caused by parenchymal haemorrhage, may follow pre-operative vasospasm.

Adult↗
PubMed1983

Classical "parietal" neglect syndrome after subcortical right frontal lobe infarction.

The classical unilateral neglect syndrome is usually associated with lesions of the nondominant inferior parietal lobe. Symptoms typically include a disturbance of orienting and attending to sensory events. We examined three patients with a "parietal" neglect syndrome: CT-documented infarctions that involved only the subcortical right frontal lobe and basal ganglia. There was no CT abnormality in the nondominant parietal lobe. Our data support the view that for polymodal cortical association areas such as the parietal lobe, which connect a variety of distant cerebral areas including the frontal lobe and basal ganglia, damage in a part of the network may be associated with different aspects of the neglect syndrome.

Aged↗