ABSTRACT
An analysis of the concurrent incidence of aphasia and spatial disorder in 270 patients with unilateral brain damage suggests that the two functions are statistically independent. These data can also be used to estimate the distribution of left, right, and bilateral representation of linguistic and spatial functions in the population. In right-handers, sex affects the pattern of cerebral asymmetries, while the familial history of sinistrality has a stronger effect on the pattern of cerebral asymmetries in left-handers. These findings suggest that complementary specialization exists only as a statistical norm: It is suggested that differences in complementary and noncomplementary specialization may underlie individual differences in cognitive skills.
Subject(s)
Aphasia/complications , Brain Damage, Chronic/complications , Dominance, Cerebral/physiology , Language , Perceptual Disorders/complications , Space Perception/physiology , Aphasia/physiopathology , Brain Damage, Chronic/physiopathology , Brain Mapping , Humans , Perceptual Disorders/physiopathologyABSTRACT
Observations of acquired aphasia in a more numerous series of children with cortical lesions modifies somewhat the conclusions of an earlier study. Aphasic syndromes in these children seem to result almost exclusively from left hemispheric lesions in right-handers. Aphasia is more frequent, at least among the youngest children, than in adults. The factors most responsible for language disorders in these children are lesion localization and etiology.
Subject(s)
Aphasia/diagnosis , Adolescent , Brain Damage, Chronic/diagnosis , Child , Child, Preschool , Dominance, Cerebral , Dysarthria/diagnosis , Dyslexia, Acquired/diagnosis , Humans , Mutism/diagnosis , Neuropsychological Tests , Speech Production MeasurementSubject(s)
Brain Diseases/physiopathology , Brain/physiopathology , Functional Laterality/physiology , Adult , Age Factors , Female , Humans , Male , Sex Factors , Speech/physiologySubject(s)
Frontal Lobe , Language Tests , Adult , Brain Diseases/diagnosis , Female , Humans , Male , MethodsABSTRACT
A case is reported in which a patient with a vascular accident involving the posterior portion of the minor hemisphere presented a topographic memory loss and also deficits in his ability to learn certain types of new material. The study of this case has led us to re-examine spatial functioning in light of both human and animal research. Based on clinical and experimental evidence we have proposed that a unitary interpretation can account for the various spatial deficits associated with posterior righ hemisphere lesions. We have also suggested that the establishment of a spatial map for orientation probably depends not only on posterior right hemisphere structures but also may require the participation of structures which are more specifically concerned with learning and memory, such as the hippocampus or at least the connections between the hippocampus and these structures.
Subject(s)
Memory Disorders/etiology , Spatial Behavior , Cerebrovascular Disorders/complications , Cues , Hemianopsia/etiology , Hippocampus , Humans , Learning Disabilities/etiology , Male , Middle Aged , Occipital Lobe , Psychological TestsABSTRACT
A case of cortical blindness resulting from a dense ischemic lesion of both calcarine cortices (as seen on CAT Scan) was studied up till the seventh month after the initial stroke. By using mainly forced-choice procedures, similar to those previously used for testing hemianopic subjects, we were able to demonstrate the reappearance of some visual capacities, even though the patient still behaved as if completely blind in everyday life and the lesion remained as it was first seen. First, an ability to detect moving stimuli reappeared then bright flashes could be detected. At last, the patient could localize flickering spots approximately, by pointing with his hand, despite the fact that he did not really see them. As was hypothesized in cases of unilateral occipital lesions, such residual vision would likely to be subserved by extrageniculostriate pathways.
Subject(s)
Blindness/physiopathology , Visual Perception/physiology , Aged , Blindness/etiology , Brain Ischemia/complications , Color Perception/physiology , Evoked Potentials , Humans , Male , Photic Stimulation , Visual Pathways/physiopathologyABSTRACT
Neuropsychology is a new discipline placed between neurosciences (neurophysiology, neurochemistry, comparative neuroanatomy) and psychology (experimental psychology. psycholinguistics, linguistics). History of neuropsychology shows, during last and the beginning of the present centuries, a marked trend to localization and association (one center for each function, followed later by a period where globalistic trends predominate, according to which a localized lesion is important mostly because of the modification it produces in the functions of brain as a whole. During the last 30 years, the development of anatomoclinical methods and experimental neuropsychology have again given impulse to a neoassociational trend. By their importance, recent advances in the following topics are underlined: (1) The study of behaviour, particularly regarding the role of neurotransmitters. (2) The concept of "hemispheric specialization" in substitution of "hemispheric dominance". (3) The mechanisms of functional reestablishment in the central nervous system. (4) The role of genetic background and experience in the development of functions of the central nervous system.
Subject(s)
Neurology/history , Psychophysiology/history , Animals , Brain/growth & development , Brain/physiology , Brain/physiopathology , Functional Laterality , History, 19th Century , History, 20th Century , Humans , Language Disorders/physiopathology , Mental Disorders/physiopathology , Primates/physiology , Psycholinguistics/history , Psychology, ExperimentalABSTRACT
In contrast to findings in right-handed subjects with a unilateral hemispheric lesion, in the left-handed there is no significant difference in "verbal fluency) test scores between right and left lesions, nor between anterior and posterior lesions. These findings are in favour of a certain degree of cerebral ambilaterality and of a lesser focalisation of the mechanisms responsible for language in the left-handed than in the right right-handed.
Subject(s)
Brain Diseases/physiopathology , Dominance, Cerebral , Functional Laterality , Verbal Behavior , Adolescent , Adult , Aged , Humans , Middle AgedABSTRACT
Two optico-geometrical illusions--the Müller-Lyer (ML) and the Ponzo (P) illusion--have been studied in normal subjects and in patients with unilateral cortical lesions. Patients with left-sided lesions have stronger illusions than normal subjects, the increase being significant only for the ML illusion. In the case of right-sided lesions, the P illusion is weakened while the ML illusion is equivalent to that of control subjects. The findings are discussed in relation to the mode of apprehension of information.
Subject(s)
Brain Diseases/physiopathology , Dominance, Cerebral , Illusions , Optical Illusions , Adult , Female , Humans , Male , Middle AgedABSTRACT
The hypothesis is advanced that cerebral dominance includes two elements, interhemispheric specification for language (lateralization) and intrahemispheric language, specification (localization). Consequently, each type of aphasia is determined by the degree of dominance establishment (i.e., lateralization and localization) existing at the moment of brain damage. Evidence for this concept is presented through a comparison of aphasia in left-handers and "anomalous" dextrals with aphasia in childhood.
