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Four right-handed patients (69, 58 and 68 year-old men; 85 year-old woman) complained of motor difficulties with their left hand (3 cases), or both hands predominant on the left side (1 case). Continuous (1 case) or intermittent (2 cases) myoclonus was noted in the left arm. These disorders gradually progressed for 3 to 10 years. Clinical examination disclosed absence of motor, sensory (except in 1 case), or visual deficit. There were no cerebellar signs, no parkinsonian features (except for mild rigidity in 1 case), and no oculomotor abnormality. On the other hand, neuropsychological examination showed evidence of visuo-constructive apraxia in all cases, dressing apraxia in 3/4 cases and writing impairment in 3/4 cases. There was no amnesia, no aphasia and no intellectual impairment. MRI showed atrophy of the parietal areas, predominant on the right side. A positron emission tomography study was performed in all cases, and twice in 1 case. Cortical energy metabolism was measured using either 18 F-fluorodeoxyglucose or 15 O-Oxygen, to calculate the cerebral metabolic rate of glucose (CMRglu) or oxygen (CMRO2) respectively. Cortical metabolism was significantly decreased in the whole cortex of the right hemisphere in 3 cases, and was also reduced in the cortex of the left hemisphere, significantly in 1/3 studied planes. Moreover, regional metabolic indices (CMRO2 or CMRglu/cortex) showed a significant decrease in both the right and left posterior associative areas (temporo-parieto-occipital cortex), predominantly marked on the right side in 3 cases, indicating bilateral cortical dysfunction. At follow-up, one patient became progressively demented, another had visuo-spatial disorders indicating a lesion of both parietal areas. The relationships of our cases with the slowly progressive apraxia syndrome and with corticobasal degeneration are discussed.

Disorders of the peripheral nervous system occur at all stages of HIV infection. From 13 patients referred for a peripheral neuropathy, 9 were known to be HIV seropositive and 4 were found to be seropositive. All were Caucasian males aged 27 to 58. Ten were homosexual, 2 were drug-addicts. Patients fell into several groups: the first group was made of 5 patients, 4 asymptomatic and 1 AIDS-related-complex (ARC), with an inflammatory demyelinating polyneuropathy, acute in 1 case and subacute in 4; the CSF showed pleiocytosis in all cases. Motor conduction nerve velocities were markedly reduced and motor distal latencies prolonged. Three patients recovered spontaneously, 1 responded to corticosteroids, 1 to plasmapheresis. In the second group, 4 patients, 1 asymptomatic and 3 ARC, had a distal symmetrical polyneuropathy; CSF was normal in 2 cases. Electrophysiological studies and nerve biopsies indicated a mixed axonal-demyelinating polyneuropathy. Three patients recovered spontaneously, 1 is unchanged. Among both groups, an infiltration of mononuclear cells was found on nerve biopsies in 4 cases. The third group was made of 3 patients with AIDS who presented with a painful sensory polyneuropathy involving the distal lower limbs. Electrophysiological and pathological study of the nerve indicated axonal degeneration. No cell infiltration was found. The last patient with AIDS had a progressive meningoradiculopathy. These 4 patients died within 6 months after the onset of the neuropathy. These findings are close to those previously reported, and confirm the wide spectrum of disorders of the peripheral nervous system associated to HIV infection.

In 2 patients an isolated dystonia of one upper limb was the first sign of Steele-Richardson-Olszewski disease. This is additional evidence of the many different clinical features of the disease.

Neurological manifestations of HIV infection are recognised at different phases of the evolution of the disease. During the late stages opportunistic neuro-meningeal infections and tumors develop as a result of the immuno-suppression. There exist, however, various manifestations which evolve independently of the immune state, and seem to be directly related to the virus itself. One can distinguish central neuro-meningeal syndromes and peripheral syndromes at the onset, or at later stages. Their prognostic implications are uncertain, but often severe, for example in the case of the subacute dementias which, in this setting, may lead to death in several months. There are also other manifestations which may be self limited or slowly evolving in the central and peripheral nervous systems. The neuropathological changes are known for the dementias as mentioned above, though the characteristics lesions due to HIV infection per se remain controversial. The presence of the virus in the nervous system has been established by in situ hybridization techniques, immunohistochemistry and culture. Studies on CSF have also allowed virological (cultures) and immunological studies to be carried out. The physiopathological mechanisms for the apparent neurological effects of this virus remain hypothetical. A better understanding of these mechanisms should lead to a rationalisation of therapeutic strategies, in a disorder which would seem to be an early and persisting viral infection of the nervous system.

Recognition of the neurological symptoms and signs of the acquired immunodeficiency syndrome (AIDS) since 1982 has demonstrated the involvement of the nervous system in approximately one third of the cases. Certain opportunistic infections or tumors had been previously described in the course of immunodeficiency states of other origins: cerebral toxoplasmosis, cryptococcosis, progressive multifocal leukoencephalopathy, atypical mycobacteriosis and cerebral lymphoma. Other disorders such as subacute encephalitis raise specific etiopathogenic questions. Several of these affections can be associated or succeed each other and this is the natural course in AIDS. The detection of those conditions that are curable, among which toxoplasmosis, is of primary importance.

Visual agnosia for objects is a difficulty in recognizing objects presented visually. This difficulty can not be explained by a mental deterioration, a disorder of attention or a lack of familiarity with the object. Two criteria are essential but disputed: the absence of visual sensory difficulty necessary for adequate perception; possible recognition of the object by another sensory modality. An object is characterized by a triple representation: formal, semantic, lexical. The clinical, cognitive, pathophysiological analysis lead to distinguish 3 types of visual agnosia. 1) Aperceptive visual agnosia: patients see badly with morphological errors; the disorder concerns visual informations processing that is a necessary condition for identifying the formal representation of the object; the lesions are bilateral and involve the occipito-temporal cortex. 2) Associative visual agnosia: patients can copy, are not aphasic, but give erroneous verbal responses; the disorder concerns the links between formal representations and semantic, lexical representations; the lesions are unilateral and involve the left gyrus angularis connections. 3) Asemantic visual agnosia: patients have lost the meanings of objects and words; the disorder concerns semantic representations; the lesions are bilateral and involve the temporo-limbic cortex.