1/13. Apraxia in corticobasal degeneration.Corticobasal degeneration (CBD) is a degenerative disease that often presents with an asymmetric progressive ideomotor limb apraxia. Some apraxic subjects may fail to perform skilled purposive movements on command because they have lost the memories or representations that specify how these movements should be performed (representational deficit). In contrast, other apraxic subjects may have the movement representations but are unable to utilize the information contained in them to execute skilled purposive movements (production-execution deficit). To learn if the apraxic deficit in CBD is induced by a representational or a production-execution deficit, we tested three nondemented subjects with CBD on tasks requiring production of meaningful or meaningless gestures to command, gesture imitation, gesture discrimination, and novel gesture learning. A fourth subject with incomplete data also is presented. The results suggest that the apraxia associated with CBD is initially induced by a production-execution defect with relative sparing of the movement representations.- - - - - - - - - - ranking = 1keywords = discrimination (Clic here for more details about this article) |
2/13. Cerebellar cortical degeneration disrupts discrimination learning but not delay or trace classical eyeblink conditioning.The authors investigated classical eyeblink conditioning in a relatively rare patient, B.R., with extensive cerebellar cortical atrophy and marked sparing of the dentate nucleus. Patient B.R.'s ability to acquire and extinguish simple associations (delay and trace conditioning tasks) as well as her ability to acquire more complex associations (temporal and simple discrimination tasks) were examined. There are 2 primary findings from this study. First, B.R. showed normal acquisition and extinction in delay and trace conditioning. Second, she demonstrated a complete inability to learn associative discriminations, even in the case of a simple 2-tone discrimination within the context of a delay paradigm. The latter finding was unexpected because of the sparing of her deep cerebellar nuclei. These data suggest that the cerebellar cortex, or pathways traversing cerebellar cortex, play an important role in classical eyeblink discrimination learning.- - - - - - - - - - ranking = 8keywords = discrimination (Clic here for more details about this article) |
3/13. Neuropathology of auditory agnosia following bilateral temporal lobe lesions: a case study.Our patient was first diagnosed with auditory agnosia following his second cerebral vascular accident (CVA) in 1975 when he was 37 years old. Comprehensive follow-up examinations of auditory function were periodically conducted until his sudden death 15 years later. His brain was studied postmortem for neuropathology. Initial pure-tone audiometry revealed moderate sensorineural hearing loss in the right ear and mild sensorineural hearing loss in the left ear. However, repeated pure-tone audiometry revealed that thresholds became progressively poorer over time, bilaterally. Speech audiometry of both ears consistently revealed that the patient was unable to discriminate any monosyllabic words (i.e. speech intelligibility scores were 0%, bilaterally). In general, speech and hearing tests demonstrated that he could not comprehend spoken words, but could comprehend written commands and gestures. Postmortem neuropathological study of the left hemisphere revealed total defect and neuronal loss of the superior temporal gyrus, including Heschl's gyrus, and total gliosis of the medial geniculate body. In the right hemisphere, examination revealed subcortical necrosis, gliosis in the centre of the superior temporal gyrus and partial gliosis of the medial geniculate body. The pathological examination supports clinical results in which the patient's imperception of speech sounds, music and environmental sounds could be caused by progressive degeneration of bilateral medial geniculate bodies.- - - - - - - - - - ranking = 0.13586476245849keywords = speech (Clic here for more details about this article) |
4/13. Slowly progressive pure dysgraphia with late apraxia of speech: a further variant of the focal cerebral degeneration.We report a longitudinal neuropsychological investigation of a patient with slowly progressive pure dysgraphia. Cognitive analysis of writing errors suggested a selective impairment of the graphemic buffer. After about seven years, the patient developed an apraxia of speech. No other linguistic or generalized cognitive impairment occurred subsequently, so that, twelve years after the beginning of the disease, the patient showed complete independence in daily life and still remained professionally active. functional neuroimaging revealed hypoperfusion confined to left fronto-temporal lobe. This well-recognizable syndrome does not fit any of the cases described previously in the literature. This report therefore, adds another variant to heterogeneous clinical spectrum of focal neurodegenerative disorders, further suggesting the opportunity of their distinction from pathological processes leading to dementia.- - - - - - - - - - ranking = 0.22644127076415keywords = speech (Clic here for more details about this article) |
5/13. A case of frontotemporal lobar degeneration with progressive dysarthria.We investigated the evolution of the neurological and neuropsychological characteristics in a right-handed woman who was 53-years-old at the onset and who showed personality changes and behavioral disorders accompanied by progressive dysarthria. She had hypernasality and a slow rate of speech with distorted consonants and vowels, which progressed as motor disturbances affecting her speech apparatus increased; finally, she became mute two years post onset. Her dysarthria due to bilateral voluntary facio-velo-linguo-pharyngeal paralysis accompanied with automatic-voluntary dissociation fit the description of anterior opercular syndrome. She showed personality changes and behavioral abnormalities from the initial stage of the disease, as is generally observed in frontotemporal degeneration (FTD), and her magnetic resonance image showed progressive atrophy in the frontotemporal lobes; thus, she was clinically diagnosed with FTLD. This patient's symptoms suggest that FTLD, including bilateral anterior operculum degeneration, causes progressive pseudobulbar paretic dysarthria accompanied by clinical symptoms of FTD, which raises the possibility of a new clinical subtype in the FTLD spectrum.- - - - - - - - - - ranking = 0.090576508305659keywords = speech (Clic here for more details about this article) |
6/13. Progressive loss of speech output and orofacial dyspraxia associated with frontal lobe hypometabolism.Three patients are described with slowly progressive loss of speech and dysarthria associated with orofacial dyspraxia, initially with intact written language, who subsequently developed more widespread cognitive abnormalities. Positron emission tomography (PET) revealed bifrontal hypometabolism in all of the patients, most marked in the inferior and lateral portions of both frontal lobes, with some extension into the parietal and temporal cortices in one case. These patients may represent a further example of focal progressive cortical degeneration.- - - - - - - - - - ranking = 0.22644127076415keywords = speech (Clic here for more details about this article) |
7/13. Neuropathological findings in a suspected case of childhood schizophrenia.The ventral tegmental area (VTA) is the major dopaminergic (DA) center responsible for the innervation of the prefrontal cortex, nucleus accumbens, and entorhinal region. These areas have been causally implicated in schizophrenia. Thus, the existence of brainstem pathology could explain many of the previously reported findings in schizophrenic (SC) patients. The authors focus on uncovering brainstem abnormalities in schizophrenia by studying the autopsied material of a patient having an early onset of symptomatology. The patient was evaluated at the age of 10 years for manneristic behavior, a speech disorder, and violence. Prominent auditory hallucinations became apparent years later. His mental status and ability for self-care steadily deteriorated until he succumbed to pneumonia at age 22. Microscopic examination of the brain showed central chromatolysis of neurons and mild gliosis in a restricted distribution of the brainstem and thalamus. Cell loss and cytoarchitectural disruption were evident in the frontal lobes, prepyriform cortex, and entorhinal region. The neuropathological changes were interpreted as a chronic derangement in the function of neurons of the rostral brainstem tegmental area and medial thalamus with secondary involvement of their terminal projection sites.- - - - - - - - - - ranking = 0.04528825415283keywords = speech (Clic here for more details about this article) |
8/13. Anatomical study of a posterior cerebral lesion producing dyslexia.After an "occipital lobectomy" that resulted in a severe dyslexia and a moderate dysgraphia-dyscalculia, anatomical study showed damage to the posterior extremity of the angular gyrus and degeneration in the posteroinferior pulvinar. This is in contrast to an earlier case that had degeneration in the anterosuperior pulvinor associated with a small anterior temporoparietal infarct and a well-documented receptive-expressive aphasia. However, the role of the pulvinar in speech function remains uncertain. The surgeon should be aware of the short distance between the angular gyrus and both the midline and the occipital pole because a lesion here during an "occipital lobectomy" produces a distressing and durable speech impairment.- - - - - - - - - - ranking = 0.090576508305659keywords = speech (Clic here for more details about this article) |
9/13. A familial progressive neurodegenerative disease with 2-oxoglutaric aciduria.A boy and a girl born to a consanguineous Tunisian couple are suffering from a slowly progressive nervous disorder. Initially they both had normal psychomotor development with acquisition of gait and speech. First symptoms in the boy were athetoid movements during the second year of life. He later lost all motor and language skills and developed muscular rigidity and intention tremor. At the age of five years, he was completely bedridden while he appeared mentally much less affected. His younger sister followed a similar course. The major specific abnormality detected was a strikingly elevated excretion of 2-oxoglutaric acid, which was identified by gas liquid chromatography, mass spectrometry, and enzymatic analysis. 2-oxoglutarate dehydrogenase activity in homogenates of cultured skin fibroblasts was reduced to about 25% of control values in both children. Although the pathogenetic mechanisms leading to brain damage remain obscure, the finding strongly suggest an autosomal recessive neurometabolic disease with predominant involvement of the extrapyramidal system.- - - - - - - - - - ranking = 0.04528825415283keywords = speech (Clic here for more details about this article) |
10/13. adult-onset of tangier disease: 1. Morphometric and pathologic studies suggesting delayed degradation of neutral lipids after fiber degeneration.A 67-year-old woman, with the typical biochemical features of tangier disease, had a syringomyelia-like syndrome which has now been observed in several patients with symptomatic onset in adult life. She developed progressive facial diplegia, bilateral wasting of hand muscles and loss of sensation over cranial, cervical and brachial dermatomes over 17 years. nociception alone was first affected, then nociception and thermal discrimination and finally all modalities of sensation. Quantified tests of cutaneous sensation confirmed that sensation was normal in lower limbs but markedly abnormal in upper limbs. Biopsied fascicles of cutaneous nerves from clinically affected (forearm) and from clinically unaffected (leg) regions permitted a comparison of well-advanced and early pathologic lesions, respectively. The selective vulnerability of unmyelinated and small myelinated fibers in affected regions in this disorder has been confirmed. The earliest morphologic abnormalities of myelinated fibers, but seen infrequently, were mitochondrial enlargement and structural abnormality, aggregation of mitochondria and dense bodies and clusters of neurofilaments. Increased numbers of sudanophilic lipid droplets did not seem to form in Schwann cell cytoplasm prior to fiber degeneration. On the contrary, for myelinated fibers there appeared to be an altered process of axonal degeneration from that seen in wallerian degeneration and in other axonal degenerations. Distinctive linear bands of closely-packed, minute, osmiophilic and clear lipid droplets formed and their further degradation appeared delayed. Although less clearly demonstrated, lipid droplets in schwann cells of unmyelinated fibers also appeared to form following their degeneration. We would propose that in tangier disease, the degradation of myelin ovoids to neutral lipid in schwann cells does not appear to be delayed. However, further degradation of neutral lipid or its transport away from Schwann cells appears to be retarded.- - - - - - - - - - ranking = 1keywords = discrimination (Clic here for more details about this article) |
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