Biomedical subjects
Publications and source records attributed to J Pellat.
The speech of a patient with aphemia (pure anarthria) resulting from a penetrating brain wound was studied using linguistic and acoustic observations as well as electromyographic recordings from four labial muscles. The results are discussed in relation to phonetic disintegration's syndrome and apraxia of speech which, respectively, enhance linguistic disorders and motor programming disturbance.
HTLV-1, HIV-1 and HIV-2 western blot analysis of sera from patients with multiple sclerosis (MS), from patients with other neurological diseases and from blood donors, revealed a rather frequent cross-reactivity with retroviral proteins in the MS group, though no patient was positive with the corresponding specific ELISA serology. Statistical analysis revealed a significant difference between the MS group and the two control groups for HIV-1 and HIV-2 reverse transcriptase fragments and for HTLV-1 p24. The general significance of these observations is discussed in the light of a retroviral hypothesis for the aetiology of MS. It is suggested that, if a retrovirus is present in MS patients, it does not necessarily belong to the HTLV sub-family and could as well be a lentivirus, like Visna virus, the causative agent of a demyelinating disease in sheep which is one--natural--model for MS.
Nine cases of post-herpetic encephalitis with predominant involvement of one temporal lobe at CT scan or MRI (6 on the left and 3 on the right sides) were studied 1 to 6 years after onset with repeated language and memory testing. The neuropsychological findings were well correlated with the lateralization and size of the lesions, as previously observed in unilateral temporal lobectomy. Compared with the usual bilateral form, the sequelae were mild, and all the patients, especially those with right hemisphere involvement, resumed a subnormal family life or social activity. In patients with left predominant lesions the anterograde amnesia concerned verbal information, especially logical and abstract, without visual amnesia. In some cases, the episodic verbal amnesia was associated with a semantic deficit which included the knowledge of some words. In one patient the colour, use and mental imagery of some objects corresponding to forgotten words were involved only for some specific groups (natural objects, whereas man-made objects fared better). Testing of verbal memory is proposed to determine the role of the preserved minor hemisphere in learning the context of word presentation, and words with concrete and visual connections which are better recalled than those with abstract or logical link. Disorders of behaviour or mood are usual in the 2 groups of lesions. Thus, herpes encephalitis in these asymmetrical and benign forms in an attractive model to study the role played by the temporal lobe and lateralization in memory.
Twenty-two patients who underwent surgery for ruptured aneurysm of the anterior communicating artery were investigated by a battery of neuropsychological tests, including memory evaluation tests. According to the results obtained at these tests the patients were divided into three groups: 1) 7 patients had no memory disorders; 2) 10 patients presented with memory disorders affecting memory; their complaints concerned behavior, and the memory deficit was discovered at neuropsychological examination; 3) 5 patients presented with an obvious amnesic syndrome, and the tests confirmed a severe learning deficit and a severe forgetting while recognition remained normal in 4 patients. Age, residual lesions at CT and electrophysiological signs of focalization correlated well with the residual neuropsychological disorders. Leaving aside quantitative aspects, the memory deficits observed in the second and third groups seemed to be qualitatively different and might correspond to different anatomical and functional sequelae.
54 patients with idiopathic Parkinson's disease (PD), 26 patients with Alzheimer's disease (AD) and 18 control subjects, all over 55, have performed neuropsychological tests, evaluating global intellectual function (Rosen's cognitive scale, WAIS digit symbol, WAIS similitude and WMS logical memory tests) and visuospatial functions (Rey lacunar pictures, Poppelreuter and Benton line orientation tests). AD group results were distinctly different from those of the PD and the control groups (p less than 0.001). In the PD group, only the Rosen's scale total score and the visuospatial tests were slightly altered (p less than 0.05). In a PD subgroup with a normal Rosen's scale result, the Benton line orientation test was different from controls (p less than 0.05). In another PD subgroup with Rosen's scale score comparable to a midly impaired AD subgroup, all the neuropsychological tests were abnormal. Only the WAIS digit symbol test, altered in this PD subgroup, was different comparing these 2 subgroups (p less than 0.05). With regard to the PD total group, the neuropsychological perturbed PD subgroup was older, had a longer duration of disease, a higher depression's score, less tremor and a worse equilibrium. These results might reflect a neuropsychological defect heterogeneity among PD patients, related to various pathophysiological hypothesis which are discussed in this paper.
A patient with an infarct in the territory of the left posterior cerebral artery, but without campimetric deficits presented with some reading difficulties and a visual agnosia restricted to the right visual field. Although the patient was able to match accurately in his agnosic field, he was unable to name or otherwise identify objects. The implications of this case for the anatomical substrates of visual processing and the functions of each hemisphere are discussed.
Following a summary of the general principles and limitations of metabolic measurements by positron emission tomography and of the different indices used to interpret the data, the authors review the results of published studies on physiological aging. Globally, with strict inclusion criteria absolute metabolic values at rest and under partial sensorial deprivation are little or not modified by age. In contrast, functional interactions between regions, as deduced from metabolic intercorrelations, are perhaps different in elderly people. In any case, positron emission tomography seems to discriminate between normal aging and different patterns of pathological aging. Technical improvements, more refined neuropsychological correlations and the use of dynamic activation paradigms will no doubt provide, in the future, a better definition of normal and pathological aging at positron tomography.
The aim of imaging the brain in Multiple Sclerosis (MS) is to prove the dissemination of lesions, so critical for the diagnosis and so difficult to ascertain clinically. Our study included 21 patients with clinically definite (12) and probable (9) MS. A 21 patients underwent a neurological standard examination, a double-dose delayed CT scan and a Magnetic Resonance Imaging with a superconducting 0.5 Tesla magnet. Jointed slices were performed with a T2-weighted Spin-Echo sequence (TE 60, 120; TR 2000 msec). MRI detected 640 lesions in 20 patients while CT scan detected only 24 lesions in 9 patients. Technical limiting factors are discussed. Abnormalities in MRI were high-intense spots, blotches and streaks, located predominantly in the periventricular area. Capping lesions were common around the ventricular horns. "Plaques" were visualized in the posterior fossa. For each patient, the total surface of the lesions was calculated and was found to be related with the presence of lesions and with the cortical atrophy on CT scan. A correlation between the surface of lesions calculated by MRI and the disability scale was found especially in the group of patients with clinically proven cerebral lesions, while patients with predominantly spinal forms had a significantly lower surface of lesions. This finding could yield a new quantitative evaluation of the MS pathologic process which could be used to assess therapeutic efficacy.
A battery of tactile tests for the study of unilateral neglect is presented with the purpose of comparing the tactile modality to the visual modality. This was applied in 4 patients with right hemisphere lesions. In 3 patients, there was evidence of neglect in both modalities with qualitatively identical anomalies. The function of spatial manipulation involved in the tasks is stressed. In the cases where both modalities were involved a supramodal hemispatial disturbance is assumed.
Tiapride, a selective D2 dopaminergic receptor blocking agent from the substituted benzamide class, was evaluated in a blind video-controlled trial in 10 psychiatric patients with tardive dyskinesia. There was a significant decrease in dyskinesia with a parallel increase in parkinsonism. This relationship between two opposite effects on movement suggests a common pathophysiological basis lying on a reciprocal hyper- and hypoactivity of the dopaminergic striatal system. Nevertheless, other mechanisms may be involved, for the evolution of individual parkinsonian and dyskinesia scores is not necessarily opposite: the tiapride-induced parkinsonism was generally acceptable and in two cases, the dyskinesia scores were reduced without an increase in parkinsonism. Therefore, more dyskinetic patients have to be evaluated in long-term studies with tiapride, before this drug could be recommended in tardive dyskinesia, when dyskinetic movements become intolerable.
The infarction in the territory of the anterior choroidal artery may induce a sensory motor impairment and neuropsychological symptoms close to those observed in some thalamic lesions. In a right handed man with a left sided infarction, language disturbances and constructional apraxia were observed. Cerebral blood flow measurements were performed 4 days after the stroke with the 133Xenon inhalation method. A decrease of mean hemispheric values was observed on both sides but more so on the left hemisphere, in the left frontoparietal regions. 98 days after the stroke language and constructional apraxia have partially improved. We have drawn a parallel between blood flow variations and neuropsychological signs. The cortical deafferentation caused by the interruption of the thalamo-cortical projections may explain the focalized decrease in cerebral blood flow values in the left hemisphere.
Palsies of the lower cranial nerves caused by a compressive pathological carotid artery are not common. Three cases of paralysis of the hypoglossal nerve, hypoglossal and vagus, hypoglossal, glossopharyngeal and vagus nerves, are reported. In 2 patients the symptoms were related to an extracranial carotid artery aneurysm below the base of the skull and in 1 patient to a spontaneous carotid dissecting aneurysm. It is possible that some localized arterial dissecting aneurysms evolve to a localized aneurysmal sac, especially if they are located between Cl and the base of the skull. The tongue paralysis disappeared in 2 patients.
The articulatory E.M.G. activity of lower lip muscles was investigated in 3 patients with Parkinson's disease and compared with normal subjects. Four paired muscles were recorded because of their antagonist function: 1) Orbicularis oris inferioris and depressor labii inferioris; 2) mentalis and buccinator. All patients evidenced well defined E.M.G. abnormalities. These consisted in the impairment of the functional organization of the antagonist muscles (lack of reciprocal inhibition), the existence of both a resting activity between utterances and a sustained hypertonic background activity during the utterance. This study was focused on the E.M.G. activity without concomitant observation of lip movement. Parallel oscillographic records of speech acoustic signals confirmed the characteristics of the voice of parkinsonian patients: low and uniform intensity, poor timbre, irregular speech rate and abnormalities of pitch.
In an open study, 30 patients with anxiety were treated with bromazepam 6 to 9 mg/day and followed-up for 15 days either as out-patients or in hospital. The results, assessed by anxiety scores, showed a 71,4% improvement, which was often perceptible as early as the third day of treatment. The best responses were obtained in patients who had not previously received anxiolytic drugs and in those who had less anxiety at the beginning of treatment. In two cases the drug was discontinued on account of daytime drowsiness.
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An acute administration of various doses of apomorphine, a dopaminergic agonist, and of dopaminergic receptor blockers (domperidone, sulpiride, haloperidol), was double-blindly achieved in a parkinsonian patient also suffering from dyskinesia. Apomorphine improved tremor and dyskinesia proportionnally to the dose. Domperidone did not prevent from this beneficial effect whereas sulpiride or haloperidol revealed a competitive antagonism versus apomorphine.
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