Dementia in adults

Accuracy of the clinical diagnosis of vascular dementia: a prospective clinical and post-mortem neuropathological study

Brains from a prospective study of demented patients were investigated post mortem. Of the 27 patients with clinical diagnosis of vascular dementia, 23 showed multiple cerebral infarcts but senile plaques and neurofibrillary tangles were absent or in insignificant numbers. This gives an accuracy of 85%, a figure higher than previously documented.

Types of multi-infarct dementia

A series of 79 patients with multi-infarct dementia (MID) were divided into 2 groups designated cortical MID and subcortical MID, according to whether the computed tomography (CT) scan showed the presence or absence of cortical infarcts, and an absent to mild or moderate to severe degree of white matter low attenuation (WMLA). Cortical MID was characterized by repeated atherothrombotic and cardiogenic strokes, moto-sensory hemiparesis, a severer degree of aphasia, and abrupt onset of cognitive failure. Subcortical MID typically showed the following features: lacunar strokes, bulbar signs including dysarthria, pure motor hemiparesis, depression and emotional lability. WMLA was found in all patients with subcortical MID but also in over 60% of those with cortical MID. In the 2 groups CT scans showed equal frequencies of deep infarcts. When divided according to severity of WMLA, 92% of patients in the cortical MID group and 44% of those in the subcortical MID group were found to have at least one cortical infarct on the CT scan. Although cortical and subcortical MID differed in several clinical features, they did not show major differences in the risk factors for stroke, and clearly overlapped each other as regards ischaemic scores and the findings in neurological examinations and CT. Thus, it is still an open question whether cortical MID and subcortical MID, including the lacunar state and Binswanger's disease, are 2 distinct entities or merely represent the expression of biological variation while having the same etiopathogenesis.

Jakob-Creutzfeldt disease. Modification of clinical and electroencephalographic activity with methylphenidate and diazepam

The electroencephalogram in three patients with Jakob-Creutzfeldt disease showed two separate abnormalities-namely, progressive background suppression and periodic generalized synchronous triphasic sharp wave complexes which evolve to a uniform morphology and periodicity. The abnormalities, when found in the EEG of a patient in middle-age with a dementing illness, should not be confused with other periodic electroencephalographic phenomena. Since the neuropathological abnormalities of Jakob-Creutzfeldt disease are non-specific, the electroencephalogram is essential for the recognition of this disorder, although serial recordings may be necessary to establish the diagnosis. Modification of the electroencephalographic abnormalities occurs with afferent stimuli and with methylphenidate or diazepam, suggesting that the phenomenon of background suppression is independent of the presence of the periodic complexes. Modification of clinical activity with methylphenidate suggests that some degree of reversibility of function exists in this inexorably fatal disorder. Further detailed studies of the electroencephalogram in cases of Jakob-Creutzfeldt disease are indicated.