Eric Levita

LATERALITY OF SUBCORTICAL INVOLVEMENT AND COGNITIVE PERFORMANCE: A FACTOR ANALYSIS

An attempt was made to clarify the nature of factors underlying verbal and perceptual performance as a function of lateralized subcortical involvement, i.e., parkinsonism. Tests requiring overt verbalization, visual and visuospatial discrimination were given to 50 Ss. Primary right or left cerebral impairment was found in 24 and 26 Ss, respectively. Two centroid factor analyses and varimax rotations yielded two major almost identical factors in both instances, specifically, visual spatial and verbal discrimination. It was concluded that laterality of subcortical impairment does not differentially affect verbal and visual spatial functions. Discussion centered on the meaning of this finding for concepts of interhemispheric duplication. Implications resulting from a postulated bilaterally distributed subcortical zone of behavioral integration were emphasized.

Thalamic correlates of language and speech

Abstract An attempt was made to compare and contrast observations and assessments made by neurosurgeons, psychologists, and speech therapists, with special reference to speech and language correlates of the ventrolateral thalamic nucleus. While findings must be considered preliminary and in need of corroboration and refinement, the following conclusions are offered: 1. (1) Alterations of fluency, presence of hesitations, and blocking in language may occur immediately after a left ventrolateral thalamic lesion in right-handed patients. These changes cannot be distinguished from dysphasia frequently described following left-sided cortical lesions. Such alterations can be definitely associated with a thalamic rather than a cortical lesion. When these alterations occur in patients operated upon unilaterally, language functions return to the preoperative level within several weeks after surgery. 2. (2) Alterations in complex language may also occur after the placement of unilateral right hemisphere thalamic lesions in right-handed patients. Such changes are ordinarily detected by tests of verbal crystalized functions involving permutations of symbols and relations among signs and symbols, rather than fluency. Findings based on such tests revealed a lack of significant qualitative differences between left and right thalamic lesions in this area, although quantitative differences are present. 3. (3) A second-sided thalamic lesion may lead to a speech impairment in the nature of dysartheia. This is not a function of the laterality of “second-side” surgery. Changes in ventrolateral thalamo-cortical connections and their effects upon cortical outflows might be related to these defects. 4. (4) Overall thalamic-cortical-thalamic circuits seem related to the language defects observed. It is proposed that alterations in linguistic fluency and flexibility following thalamic lesions can be attributed in part to a disturbance between specific and non-specific systems at a thalamic level. Such lesions may alter linguistic patterns by interfering with the activating aspects necessary to this function. At a thalamic level, greater activation may be required for adequate processing and elaboration of information. The fact that neural activating systems are essentially bilateral in nature may account for the fact that language functions seem to be more independent of lesion laterality after thalamic than cortical involvement.

VERBAL AND PERCEPTUAL FUNCTIONS AFTER SURGERY OF SUBCORTICAL STRUCTURES.

The cognitive and perceptual performance of 61 parkinsonians was studied as a function of unilateral basal ganglia surgery, specifically, chemothalamectomy and cryothalamectomy. Preoperative comparisons of non-neurological and parkinsonian Ss revealed no significant differences (p > .05). Three conclusions were warranted. (a) Cryothalamectomy does not adversely affect cognitive functions in the immediate post-operative period with the exception of greater impairment after right cryothalamectomy than after no surgery on some tasks of visual spatial performance not requiring overt verbal responses (p < .02). (b) Chemothalamectomy does not adversely affect cognition except for greater post-operative impairment on overt verbal performance after left chemothalamectomy than after left cryothalamectomy (p < .001). (c) Preoperative to long range comparisons revealed no differences between Ss undergoing surgery or no surgery (p > .05). Significantly shorter periods of time elapsed between successive testing in the case of cryothalamectomy with implications for effectiveness of treatment (p < .001, < .01). The role of subcortical structures in perceptual processes and in the elaboration of verbal behaviors was discussed.

PATTERNS OF PSYCHOLOGICAL FUNCTION BEFORE, AFTER UNILATERAL, AND AFTER BILATERAL THALAMIC SURGERY

Visual-perceptual, verbal, and short-term retention tests were administered to unilaterally operated, bilaterally operated, and unoperated parkinsonian patients. Principal component factor analyses derived for each group yielded 4 factors regardless of treatment condition. Similarities between groups pointed to consistency and overlapping among factor patterns obtaining in the presence or absence of subcortical surgery. Variations among factor structures suggested that unoperated patients are characterized by a gross, wholistic approach to perceptual-cognitive tasks. Bilaterally operated individuals show more concern with detail and specific aspects in their perceptual-cognitive style. Unilateral brain operates occupy an intermediate position. Implications for behavioral activation and the relevance of diffuse bilateral subcortical systems were emphasized.

Integrative Functions in Parkinsonism

The effects of neurological involvement upon integrative performance were assessed through visual-motor, perceptual, and cognitive test performance of parkinsonian and cardiac patients. No significant differences were obtained between the test results of parkinsonian and cardiac patients. For parkinsonian patients no significant variations in “higher integrative” functions could be attributed to differences in sex, age, extent of voluntary movement impairment, and laterality or severity of neurological involvement. Degree of autonomic nervous system impairment was related to psychological performance only in one test (“Odd Words” test). It was suggested that perceptual-cognitive performance of groups of parkinsonian Ss does not necessarily qualify as “organic” in the usual psychological sense.

PSYCHOLOGICAL FUNCTIONS IN RELATION TO LESION SIZE AND SITE IN CRYOTHALAMECTOMY FOR PARKINSONISM

The relationship of number or size and site of unilaterally and bilaterally induced thalamic lesions to psychological changes in parkinsonians was assessed by means of quantifiable tests of cognition, perception, and recent memory. In no instance was lesion size or site, within the confines of the ventrolateral nucleus of the thalamus, significantly or differentially related to cognitive or perceptual changes. These findings were discussed in terms of possible roles of thalamic nuclei in psychological functions. The “law of physiological safety,” the role of functional compensation, and the presence of relatively small lesions within a larger bilateral thalamic zone were considered in interpreting the results. Clinical implications were noted with regard to patient selection for placement of multiple lesions. The presence of wide individual differences in a brains tolerance of lesion infliction was emphasized also.

On Subcortical Correlates of Verbal Functions in Parkinsonism: Critical Considerations

Summary It would appear that, for parkinsonians, components of verbal formulation and/or expression are related to thalamic involvement and may point to the importance of functional integration at the subcortical level. On the basis of a majority, psychological studies would suggest at this time that 1. Findings on verbal-cognitive changes associated with neurological involvement were equivocal and seem to reflect differences in sampling procedures. 2. Qualitative differences in verbal-cognitive test performance were not confirmed as a function of subcortical lesion laterality. 3. Deficits in verbal functions decrease in degree or can no longer be observed within six months after surgery.

PSYCHOLOGIC STUDIES IN NEUROLOGIC DISEASES—A REVIEW: PARKINSON'S DISEASE AND MULTIPLE SCLEROSIS*

Parkinson’s disease and multiple sclerosis (hereafter referred to as P.D. and M.S. respectively) represent progressive chronic diseases of the central nervous system. A large proportion of the afflicted persons fall within the geriatric population. In each instance, the disease may result in alterations of the motor and sensory systems of the brain and spinal cord, and thus produce various abnormalities of movement and sensation. The specific et,iology in both diseases is largely unknown (although continuing investigations reveal much new information concerning the pathology) and this lack of knowledge has thus far prevented the development of any specific therapy. Recently chemosurgery has been found useful in the symptomatic relief of both P.D. and M.S., specifically in alleviating certain of the associated abnormal movements (1-3). Because of the manifold neurologic symptoms, the relative obscurity of the etiologic factors, the lack of specific treatment, and the many and diverse behavioral effects of these diseases, recent years have witnessed an increase of investigations concerning their psychologic and psychiatric aspects. It is the purpose of the present review to summarize a portion of these investigations, most specifically those which may provide information concerning the relationship between psychologic factors, neurophysiologic substrata, and the resulting disease processes and symptoms. Thus, this review is not intended to be all-inclusive, but limited rather to those studies concerned directly or indirectly with psychosomatic and somatopsychologic relationships.

Spinal Cord Stimulation Revisited: Psychological Effects

97 patients undergoing spinal cord stimulation (SCS) were studied for a median of 24 days after initiation of treatment. SCS was associated with significant improvement in memory, visuo-spatial integration, activation, cognitive efficiency, attention and overall psychological status. Significant emotional improvement in self-image, anxiety and depression was also confirmed following SCS. Diagnosis did not differentially affect psychological outcome except for relief of anxiety, which was less pronounced in the case of torticollis and multiple sclerosis. The role of spinal cord modulation of behavioral activation and physiological arousal was discussed.

Psychological Effects of Spinal Cord Stimulation: Preliminary Findings

22 patients undergoing spinal cord stimulation (SCS) were studied for a period ranging from 4 to 6 weeks following initiation of treatment. SCS did not alter cognitive, perceptual or visuomotor effici