Progressive prosopagnosia at a very early stage of frontotemporal lobar degeneration
ABSTRACT Background: The present paper describes a patient with a right temporal lobe variant (RTLV) of frontotemporal lobar degeneration (FTLD).Methods: The study was undertaken when the patient was completely independent in her environment and had not complained of any cognitive problems.Results: Under general neuropsychological assessment, the patient showed no notable deficit other than a difficulty in recognizing famous people by looking at photographs of their faces. Subsequent in-depth evaluation indicated prosopagnosia: the patient presented with an impaired ability to recognize the faces of famous people and family members, whereas her visuospatial abilities were intact. Because the patient was able to recognize familiar people by their voices, the impairment was not a general loss of knowledge about people, but an inability to access this knowledge from visual stimuli (i.e. via the visual modality). The patient also exhibited a ‘within-category’ learning deficit; however, her ability to learn from ‘across-category’ visual stimuli remained intact.Conclusions: Overall, the results of the present study support the proposed model of RTLV of FTLD, where the first sign would be the disruption of face recognition components, leading to a selective form of associative prosopagnosia. Further, the co-occurrence of face and ‘within-category’ object learning deficits favor an interpretation in which a more generalized deficit occurs ‘earlier’ in the sequence of events associated with the object recognition process.
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ABSTRACT: The energy release rate criterion, being mono scale by definition, is incompatible with the failure behavior of solids that are inherently dual, if not, multiscale. Time span of reliability is scale sensitive and can be addressed with consistency only by use of transitional functions that are designed to transform a function from one scale to another. A pseudo transitional energy release rate G∗ is defined to address the cross-scaling properties of energy release rate. The reliability of such a function is found to fall quickly when the scale range deviates from that of micro–macro. In general, the time span of reliability based on G* shortens considerably within the nano–micro and pico–nano scale ranges, resulting in fast turnover of system usability. Prediction accuracy tends to be scale range specific. Stress or strain based criteria are also mono scale. They may be adequate for some situations at the macroscopic scale, but can be ambiguous for multiscale problems. These situations are analyzed by application of the principle of least variance in conjunction with the R-integrals.Accelerated test data for the equivalent of 20years’ fatigue crack growth in 2024-T3 aluminum panels were analyzed using the mutliscale reliability model. A time span plateau within the micro–macro range is from 8 to 17years. This corresponds to the reliable portion of prediction, while the terminal 3years are regarded as unreliable. A similar time span plateau were also found from 4 to 6years within the nano–micro scale range. And an even smaller plateau hovering around 1.2years were found for the pico–nano scale range. Time span of reliable prediction narrows with down sized scale range. The overlapping ends of the scale ranges are rendered unreliable as anticipated. These regions can be suppressed by the addition of meso scale ranges. Reference can be made to past discussions related to multiscaling and mesomechanics.Theoretical and Applied Fracture Mechanics - THEOR APPL FRACT MECH. 01/2011; 55(1):52-59.
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ABSTRACT: The construct of associative prosopagnosia is strongly debated for two main reasons. The first is that, according to some authors, even patients with putative forms of associative visual agnosia necessarily present perceptual defects, that are the cause of their recognition impairment. The second is that in patients with right anterior temporal lobe (ATL) lesions (and sparing of the occipital and fusiform face areas), who can present a defect of familiar people recognition, with normal results on tests of face perception, the disorder is often multimodal, affecting voices (and to a lesser extent names) in addition to faces. The present review was prompted by the claim, recently advanced by some authors, that face recognition disorders observed in patients with right ATL lesions should be considered as an associative or amnestic form of prosopagnosia, because in them both face perception and retrieval of personal semantic knowledge from name are spared. In order to check this claim, we surveyed all the cases of patients who satisfied the criteria of associative prosopagnosia reported in the literature, to see if their defect was circumscribed to the visual modality or also affected other channels of people recognition. The review showed that in most patients the study had been limited to the visual modality, but that, when the other modalities of people recognition had been taken into account, the defect was often multimodal, affecting voice (and to a lesser extent name) in addition to face.Neuropsychology Review 04/2013; · 6.42 Impact Factor