Jeffrey Rosen

Depression, intellectual impairment, and Parkinson disease

To determine the prevalence of depression in Parkinson disease (PD) we evaluated 55 consecutive patients without dementia and 31 of their spouses. All subjects completed the Beck depression inventory and a quantitative mini-mental state examination. Using the Beck criteria, 47% of the patients and 12% of the spouses rated themselves as significantly depressed. Mental state scores were significantly lower in the patients. There was a correlation between the severity of depression and cognitive impairment, particularly for calculation, digit span, and visuomotor skills. The severity of parkinsonism, particularly bradykinesia, also paralleled cognition. There was a slight but significant relationship between parkinsonism and depression. These results confirm the high incidence of depression in PD, and suggest that depression in Parkinson patients may be accompanied by mild intellectual impairment and inattention which is independent of the severity of the illness.

Interictal memory and language impairment in temporal lobe epilepsy

Memory and language were evaluated in patients with temporal lobe epilepsy and generalized epilepsy. Subjects were matched for age, duration of illness, and seizure frequency, and grouped according to the electroencephalographic results and seizure type into right temporal, left temporal, and generalized. In formal tests of intelligence, auditory and visual memory, and language, a significant difference was noted only on a confrontation naming test. The mean score on this test was considerably lower in the left temporal group; right temporal and generalized groups scored in the normal range. This decrement correlated with impairment on many verbal subtests of intelligence and memory. These results suggest that the interictal memory impairment of temporal lobe epilepsy may be an anomia and that the anomia may contribute to impairment of verbal learning and memory; both circumlocution and circumstantiality may compensate for anomia.

Perceptual motor dysfunction in Parkinson's disease: a deficit in sequential and predictive voluntary movement.

We studied the ability of Parkinsonian patients and controls to generate voluntary movements on a tracing task. Subjects were videotaped while tracing designs of increasing complexity, presented on a vertical, transparent screen. Some designs were presented in a degraded form and subjects filled in their missing sections. Subjects also received a constructional task and a test of general intellectual ability. The quality of errors on the tracing task differed in the Parkinsonian and control groups. Parkinsonian patients made two distinct types of errors. One probably related to the motor disorders of the disease, but another seemed to be related to a higher level of control over sequential and predictive movements. The latter correlated with performance on the constructional and general intellectual tasks. These results suggest that Parkinsons disease may affect basal ganglia structures that are necessary for voluntary movements which require sequencing or planning. Clinically this may be observed in perceptual motor tasks since they require both voluntary movement and sequential organisation of behaviour.

Tip-of-the-tongue phenomenon in Parkinson disease.

Articulatory disturbances are frequently described in Parkinson disease, but language disorders are not. We have occasionally encountered parkinsonian patients with word-finding difficulty unrelated to memory loss, intellectual impairment, or dysarthria. To examine this, 22 medically stable parkinsonian patients were given the vocabulary subtest of the WAIS, the Boston Naming Test, measures of verbal fluency, and sentence repetition. Signs and symptoms of parkinsonism were rated. WAIS vocabulary subtest scores were above the mean for normal aged subjects, but confrontation naming was one standard deviation below norms for age and education. Naming was facilitated by cues in most patients. Only sentence repetition correlated with dysarthria. Category naming was impaired and correlated significantly with the severity of parkinsonism, especially bradykinesia. This suggests that a type of anomia may occur in Parkinson disease. It shares the clinical characteristics of the “tip-of-the-tongue” phenomenon and “word production anomia” seen in some aphasics.

Behavioral Effects of Sequential and One-Stage Ablations of Orbital Prefrontal Cortex in the Monkey

Abstract The purpose of this investigation was to determine whether sequential (i.e., serial) ablation of the monkeys orbital prefrontal cortex would lead to a reduction in the severity of the behavioral impairment usually associated with one-stage bilateral removal of this tissue. The lateral orbital cortex was ablated in four operations spaced 3 weeks apart or in a one-stage procedure. The monkeys were examined on a visual go-no go differentiation task, spatial delayed-alternation, and object reversal learning. The results reveal no differences between the effects of sequential and one-stage ablations. These findings differ from previous experiments that demonstrated a degree of functional recovery after the sequential removal of a sector of the dorsolateral prefrontal cortex. Since lesion studies with infant monkeys have also demonstrated that functional recovery occurs after early ablation of dorsolateral cortex but not after early removal of orbital frontal cortex, recovery of behavioral functions after infant and sequential lesions may involve similar neural mechanisms.

Tachistoscopic word recognition performance under conditions of simultaneous bilateral presentation

Abstract Four experiments involving the bilateral tachistoscopic presentation of word pairs are reported. This paradigm was found to generate a right hemi-field recognition advantage across manipulations of word orientation, exposure duration, and fixation control. In two of the experiments this recognition asymmetry was maintained in spite of a significant tendency to initiate the verbal report with any available left hemi-field content. In three of the experiments the strength of the left to right order of report tendency was negatively correlated with the magnitude of the right visual field recognition advantage. A hypothesis to account for the more common finding of left hemi-field recognition superiority with bilateral displays is offered.

Prism adaptation in Parkinson's disease.

Prism adaptation is impaired by lesions in the basal ganglia in non-human primates, suggesting that this area is involved in this form of visuomotor learning. We investigated the ability of patients with Parkinsons disease to prism adapt. Patients and controls wore prisms which deflected vision laterally by 11 degrees. After baseline testing with a localisation task that permitted no feedback about performance accuracy, prism adaptation was tested at 4 minute intervals over a 28 minute trial. All subjects erred initially, reaching too far to the left of the target, but a separate pointing task encouraged adaptation and reaching error decreased at a similar rate in Parkinsonians and controls. Immediately after the prisms were removed, all subjects reached to the right of the target. This negative after effect was present in controls but not patients when assessed 4 minutes later, suggesting that the patients could not maintain the new sensorimotor relationship imposed by the prisms after their removal. This is similar to performance on visuospatial and executive tasks in Parkinsonians, where ongoing behaviour cannot be modulated without external guidance.

Simple reaction time as a measure of global attention in Alzheimer's disease

Alzheimers disease (AD) is characterized by progressive decline in memory, language and other cognitive functions. Deficits in attentional processes have also been suggested. A simple reaction time (RT) task was used to assess global attention in AD. The length and consistency of a warning signal given prior to the response stimulus were manipulated to determine if patients with AD and age-matched controls benefit from predictability in RT tasks. Overall reaction time was slower in the AD group than in the and control group. Both groups demonstrated significant improvement in RT with long warning signals compared to short warning signals, but only the control group benefited from the consistency of the warning.

Superior recall of letters in the right visual field with bilateral presentation and partial report.

The present investigation addresses itself to the question of whether a right visual field effect would emerge under conditions of bilateral letter presentation and partial report. Tachistoscopic trials consisting of eight letters, four in each field, were presented for 100 msec., to twenty right-handed adults. Ss were instructed to report the content of only one field on each trial. Under these conditions a right field superiority was obtained and an interaction between field and stimulus position. The field asymmetry appears to reflect the operations of cerebral dominance while the interaction suggests the influence of mnemonic factors.

A comparison of two- and four-stage ablations of sulcus principalis on recovery of spatial performance in the rhesus monkey

Abstract In adult rhesus monkeys lesions of sulcus principalis inflicted in four stages result in less severe deficits on a battery of spatial tasks than smaller lesions of the same area created in 2 stages. The amount of intact tissue remaining after each operation appears to be a more important factor in predicting recovery than the duration of the interoperative interval.