[The symptomatology of frontal and temporal lobe damages]

In this paper, we review the symptoms associated with damages to the frontal and/or temporal lobes. Similarities and differences between the symptoms observed after a stroke and in frontotemporal lobar degeneration are also discussed. Frontal lobe damages may lead to various apraxic disorders, including limb-kinetic, ideomotor, gait, buccofacial, and ocular motor apraxia. Language dysfunction can arise from perisylvian lesions as well as from extra-perisylvian regions. Broca's aphasia, Wernicke's aphasia, pure word deafness, and aphemia are typical examples of disorders caused by damages to the perisylvian region. Transcortical motor and anomic aphasias are mostly associated with damages to the extra-perisylvian region. Although it has been reported that executive dysfunction is associated with damages to the frontal lobe, it remains to be determined whether there is a cause-and-effect relationship between the 2. A combination of memory, attention, emotional, and mood disorders may underlie executive dysfunction. Patients with lesions in the inferior temporal lobe often present with various types of agnosia. Visual agnosia is common in semantic dementia, but is infrequent after a stroke in the temporal lobe. Prosopagnosia is a rare consequence of damages to the temporal lobe. Bilateral and right-sided lesions are likely to cause this disorder than left-sided lesions. Although, prosopagnosia is less frequently observed than visual agnosia in semantic dementia, it still is one of the common features of the disease. Bilateral injuries to the mesial temporal lobes have been known to induce a marked amnesic syndrome. It is devastating in that the patient can remember virtually nothing new. However, memories acquired before the injuries are mostly conserved and the patient can still learn motor skills.