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Objective: To make a review of the literature on alterations in mathematical ability secondary to structural cerebral lesions., Development and Conclusions: We refer to the initial classification of acalculia of Berger (secondary acalculia when this is due to broader neuropsychological deficits and primary acalculia when it occurs alone) to the classical division of Hecaen (alexia and numerical agraphia with or without alterations in reading and writing of letters and words, visuo-spatial acalculia due to alterations in the spatial organization of multi-digit figures and the partial results of arithmetical operations, anarithmetia or primary failure in mathematical ability) and the most recent classifications based on neurocognitive models, which subdivide the acalculias into those secondary to changes in the system for processing numbers and those due to changes in the cognitive system for mathematics (McCloskey and Caramazza). Similarly, we review the correlations between the clinical changes in mathematics and the cerebral localization of the causative lesions (left parieto-temporal, right and including frontal and subcortical associative areas) together with the association of acalculia and other neuropsychological deficits. Finally we review the neuropsychological instruments available for the evaluation of acalculias, with particular reference to the tools validated and scaled for our language and sociocultural setting.

Chronic instability is a frequent complaint in elderly patients. As literature on the subject is scarce, we investigated reversible causes, evaluating patients over 65 years of age referred to a regional neurological practice for disequilibrium lasting longer than three months. Clinical features were analyzed. Computerized tomography (CT) of the brain, and thyroid hormone and cyanocobalamin (Cc) serum levels were studied for all patients, as was clinical course. No CT abnormalities were found. Low Cc levels were observed in 6 patients, and 2 were diagnosed of previously undetected hypothyroidism. During the mean follow-up period of 12 months, improvement was seen in 3 specifically-treated patients, one with hypothyroidism and two with Cc deficit. We conclude that chronic instability in the older patient cannot usually be traced to a specific cause, but that it is important to protocolize the assessment of such patients, including routine tests for thyroid hormone and Cc levels, in order to rule out treatable causes.

The local expression of tuberculous meningitis has an high incidence. They respond to a Koch bacillus direct lesion or vasculitis disease. The clinic implication of ocular movement is frequent and usually answers to a nervous trunk direct injury. Exceptionally the clinic expression of the oculomotor disturbance is due to a conjugate ocular tract or nucleus damage. The posterior internuclear ophthalmoplegia is a well-known manifestation and correspond with a dwindle of the medial longitudinal fasciculus electrical transmission and lies in falling of the medial rectus to move synchronously with the contralateral rectus on attempted lateral gaze to either side. In such a case the medial longitudinal fasciculus is damaged between the sith nerve nucleous below and the opposite third nerve nucleus above. A patient with AIDS B3 category who presents right internuclear ophthalmoplegia and right eye vertical conjugate gaze impairment with left vertical nystagmus due to a paramedial mesencephalic stroke as debut of a linfocitary subacute meningitis is present.