RESUMO
The alien hand syndrome (AHS) usually consists of an autonomous motor activity perceived as an involuntary and purposeful movement, with a feeling of foreignness of the involved limb, commonly associated with a failure to recognise ownership of the limb in the absence of visual clues. It has been described in association to lesions of the frontal lobes and corpus callosum. However, parietal damage can promote an involuntary, but purposeless, hand levitation, which, sometimes, resembles AHS. In the present study, four patients (cortico-basal ganglionic degeneration -- n=2; Alzheimer's disease -- n=1 and parietal stroke -- n=1) who developed alien hand motor behaviour and whose CT, MRI and/or SPECT have disclosed a major contralateral parietal damage or dysfunction are described. These results reinforce the idea that parietal lobe lesions may also play a role in some patients with purposeless involuntary limb levitation, which is different from the classic forms of AHS
Assuntos
Humanos , Masculino , Feminino , Pessoa de Meia-Idade , Encefalopatias/complicações , Mãos , Transtornos dos Movimentos/etiologia , Lobo Parietal/patologia , Doença de Alzheimer/complicações , Doença de Alzheimer/diagnóstico , Atrofia/complicações , Atrofia/diagnóstico , Doenças dos Gânglios da Base/complicações , Doenças dos Gânglios da Base/diagnóstico , Encefalopatias/diagnóstico , Córtex Cerebral/patologia , Imageamento por Ressonância Magnética , Transtornos dos Movimentos/diagnóstico , Doenças Neurodegenerativas/complicações , Doenças Neurodegenerativas/diagnóstico , Acidente Vascular Cerebral/complicações , Acidente Vascular Cerebral/diagnóstico , Síndrome , Tomografia Computadorizada de Emissão de Fóton ÚnicoRESUMO
The aim of this study was to compare the accuracy of computed tomography (CT) and single photon emission computerized tomography (SPECT) in the diagnosis of dementia. Fifty-two patients with clinical diagnosis of dementia and 11 controls were studied. The scans were interpreted by one experienced neuroradiologist and one nuclear radiologist, both blinded to the clinical data. In the diagnosis of dementia, CT and SPECT showed equal sensitivity (82.7 per cent) and statistically similar specificity (63.8 and 81.8 per cent, respectively). The specificity of SPECT in diagnosing Alzheimer's disease (100 per cent) was statistically superior to CT (69 per cent). However, both methods showed similar sensitivity in detecting Alzheimer's disease. In conclusion, SPECT and CT showed similar accuracy in the diagnosis of dementia. The quite high specificity of SPECT in Alzheimer's disease may be useful for confirming that diagnosis, particularly for patients with presenile onset of the disease.