Age at onset and SPECT imaging in Alzheimer's disease.

It is generally accepted that presenile Alzheimer's disease (AD) has faster progression and severer clinical manifestation than senile onset AD. Recently a relative left frontal hypoperfusion was only found in patients with presenile AD by using SPECT imaging. The aim of the present report was to ascertain whether the same conclusion could be drawn matching the population with respect to the severity of the cognitive profile and disease duration. Twenty subjects for each group were studied with SPECT and no differences emerged between groups. It is postulated that presenile and senile onset AD represent aspects of the same biological process.

Paroxysmal dystonia due to a lesion of the cervical cord: case report.

A 48 year old woman complained of mild weakness and paresthesias of the left limbs, followed 15 days later by episodes of paroxysmal dystonia of the left limbs occurring several times daily over 10 day period. Magnetic resonance imaging (MRI) of head and neck revealed a small area of altered signal in the T2-weighted sequences in the left posterolateral quadrant of the cord at the second cervical vertebra. An MRI scan 18 months later showed no lesion. This is the second case of paroxysmal dystonia with a single MRI lesion in the cervical region on record.

Fuld's formula and WAIS subtests in differential diagnosis of dementia.

The Fuld formula and the linear discriminant function applied to WAIS subtest scores were tested for their ability to identify Alzheimer's disease and senile dementia of the Alzheimer type in a group of 101 demented subjects. The sensitivity and specificity of Fuld's formula for Alzheimer dementia against other dementias were 44.2% and 73.8% respectively; when compared with an age-matched normal control group specificity was 91.4%. When the linear discriminant function was applied only WAIS subtest scores in "similarities and digit span" and "object assembly" significantly differentiated Alzheimer from other dementias (sensitivity 61.5% and specificity 63.3%). Specificity increased to 97.1% when the function was applied to discriminate Alzheimer from normal controls. Discriminant analysis applied to other WAIS subtests for the two demented groups revealed "picture completion" as significantly differentiating the groups but it did not contribute to diagnostic accuracy. WAIS scores are of limited value in the differential diagnosis of dementias.

Transient global amnesia: a large series with neuropsychological examination and a case-control study.

We studied a large series of patients with transient global amnesia (TGA). Clinical and neuropsychological evaluations are reported. A case-control study provides some arguments against the hypothesis of cerebrovascular ischemia as a main etiology for TGA.

The differential contribution of the verbal code in the course of visual learning: evidence from hemisphere-damaged patients.

Control patients and patients with hemispheric lesion were given a paired-associate memory test made up of meaningful figures and their performance was compared on two measures: number of errors over the first three trials and trials to criterion. Impairment on the former measure was associated with left brain damage and found to be related to the degree of aphasic deficit, suggesting the involvement of the verbal code in the early stages of the learning process. However, analysis of trials to criterion showed that a defective performance was confined to patients of either hemispheric group having posterior lesions and bore non relationship to measures of language impairment. It is inferred that, as the learning process consolidates, the aid provided by verbal mediation to recognizing visual images progressively recedes.

Spatial memory and hemispheric locus of lesion.

Corsi's cube test was given to 40 control and 80 brain-damaged patients to assess the relation of different aspects of spatial memory to the hemispheric locus of lesion. Spatial span was found affected by injury producing visual field defect (VFD), regardless of the side of the lesion. Delayed reproduction of a 3 cube sequence (which was within the span of every patient) was performed more poorly by patients with right hemisphere damage and VFD than by controls. This was true whether the delay was unfilled or filled with a counting activity, the two conditions being equally effective in bringing about the inferiority of the right brain-damaged group. Learning to criterion up to a maximum of 50 trails a supraspan sequence was failed by 65% of right brain-damaged patients with VFD, a percentage significantly higher than that found not only in the control group, but also in any other brain-damaged group. These findings point to the dominant role played by the posterior region of the right hemisphere in subserving spatial memory mechanisms, especially when the acquisition of stable traces is requested.