Anosognosia For Hemiplegia: Intrahemispheric Anatomy

Abstract

OBJECTIVE: Anosognosia for hemiplegia can be defined as patient’s denial of disorder and ignorence of deficit. In the definition there is denial phenomenon which is unawareness of deficit and relevant behavioral pattern. Although there are too many explanatory scientific explanations that express the disorder as neural some psychologic factors (such as defence mechanisms or depression) are also mentioned as effective factors in the development of hemiplegia for anosognosia. The most important evidence of neural mechanisms is, the sign that is frequently observed in right hemisphere lesions and besides, patients implicated amytal to right carotid artery are not aware of motor deficits. For years, hemiplegia for anosognosia is considered as an important sign of parietal lobe lesions. On the other hand, anosognosia for hemiplegia is also experienced by deep, basal ganglionic and/or thalamic lesions.

OBJECTIVE: In this study we aimed to explore the relation between inter and intrahemispheric location of hemiplegia for anosognosia, accompanying neurologic and neuropsychologic findings and by this way highlightening the pathogenesis of hemiplegia for anososgnosia.

METHODS: In Department of Neurology, School of Medicine, Çukurova University, Adana, Turkey, in total of 85 patients hospitalized by first supratentorial stroke diagnosis, 56 of which are with ischemic infarction and 29 of which intracerebral hemorrhage patients acute phase of hemiplegia for anosognosia have been investigated. All patients had at least 5 years of formal education. 54 of them had right, 31 of them had left hemisphere involvement. Besides structured interview for anosognosia form which has been proposed by Starkstein et al (1992), detailed neurological examination, hemispatial, sensorial and motor neglect, motor persistence, constructional ability, Gülhane Praxis Test, Hamilton Depression Scale (HDS) are also administered to all patients. Evaluating the cerebral CT findings, Gilbert et al’s (1986) and Alexander et al’s (1987) cerebral CT atlas have been used.

RESULTS: Hemiplegia for anosognosia has been determined in 19 (22.3%) of 85 patients, 17 had right, 2 had left hemisphere lesion. In hemiplegia for anosognosia patients sensorial deficit (p<0.01), sensorial neglect (p<0.001), hemispatial neglect (p<0.05), motor impersistence disorder (p<0.005) are observed more often than patients without hemiplegia for anosognosia. Patients with hemiplegia for anosognosia, putamen (p<0.001), superior parietal lobule (p<0.005) and inferior temporal gyrus (p<0.005) have been affected more than other brain structures. HDS did not show significant difference between patients with and without hemiplegia for anosognosia.

CONCLUSION: Our findings have confirmed hemiplegia for anosognosia as an right hemisphere sign. Especially it is observed on lesions occupying parietal and temporal structures and the lesions affecting basal ganglia. All these findings suggested hemiplegia for anosognosia as certain structures of right hemisphere (blocking neural network) involvement rather than psychological factors. However we should keep in mind that structured interviews based on verbal communication are not capable enough in patients with language problems to figure out existence of hemiplegia for anosognosia