Psychological changes correlated with thalamotomy site

Abstract

SUMMARY The effects of surgically placed thalamic lesions on cognitive skills, as measured by psychological tests, are dependent upon the nature of the skill and the site of the lesion. Lesions within the limits of the centrum medianum nucleus produce few deficits, whereas lesions outside its limits result in deficits for a greater number of skills. In general, the more complex skills revealed more impairment and the deficits were long lasting.The function of the thalamus in relation to cognition, as reflected by psychological tests, was evaluated in patients treated by thalamotomy for Parkinsonism, seizure, and pain disorders.The psychological tests are considered under four categories and correlated with lesions placed within and outside the limits of the centrum medianum nucleus. The age of patients with Parkinson's disease ranged from 37 to 72 years and those with seizure and pain disorders from 20 to 62 years. METHOD SURGICAL PROCEDURE Lytic lesions were made stereotaxically under local anaesthesia. A 20 gauge barrel electrode with a 3 to 4 mm non-insulated tip was inserted into the diencephalon through a frontal burr hole at an angle of approximately 40 to 45°. Electrical stimulation followed by an electrolytic lesion was performed as previously described (Andy, Jurko, and Sias, 1963;Andy, 1966 TEST RESULTS AND LESION SITE The data were analysed by plotting results derived from each of the tests in relation to the locus of the lesion. Scattergrams were used for plotting the lesions on horizontal planes through the thalamus at the level of the centrum medianum nucleus (+ 3-5 mm). This plane was chosen because the maximum size of the lesion was at that approximate location of the thalamus, and the greater variability in these patients was in relation to the mediolateral and frontoposterior positioning of the lesion. The statistics used, where applicable, were the 2 x 2 x2 test, and the two-tailed binomial expansion test. RESULTS

Effects on cognition and quality of life with unilateral magnetic resonance–guided focused ultrasound thalamotomy for essential tremor

“…2,23,29,32 Many studies have reported that thalamotomy is associated with a risk of cognitive deterioration, especially score reductions in verbal fluency or verbal memory following left-sided procedures. 34,40 With regard to ventral intermediate nucleus (Vim) DBS, verbal fluency could diminish relative to baseline in about 10% of patients, though overall cognitive function was stable due to compensation for improved visuomotor or verbal memory function.…”

Bilateral Neuropsychological Deficits in Unilateral Paramedian Thalamic Infarction

“…The pattern of the neuropsychological deficits in the latter infarctions allows a definite determination of the side of the cortical lesion. However, neuropsychological studies concerning a laterality effect for patients with unilteral thalamic infarc tion have reported conflicting results: some studies have led to the purpose that hemispheric specialization extends to the thalamus [6][7][8][9][10][11]. On the other side, Alexander and Lo Verme [ 12] found bilateral neuropsychological deficits after unilateral thalamic lesions, whereas Wallesch et al [13] found no laterality effect.…”

Post-Lesion Yawning and Thalamotomy Site

“…For Necker cube reversal rates it was found that lesions placed me dially in the center-median nucleus increased reversal rate in contrast to laterally placed lesions which decreased the rate of reversal [4], Another study indicated that the lesion site within the center-median nucleus was related to the degree of improvement for specific behavioral categories. For aggression maximum improvement occurred for medially placed le sions, whereas there were no differences in degree of improvement for hy perkinesia and patho-affect relative to medially or laterally placed lesions [11-Yawning was elicited by bilateral stimulation of the cingulum in two 17-year-old brain-damaged patients [2].…”