Allochiria for spatial landmarks as the presenting feature of posterior cortical atrophy.

Allochiria refers to the mislocation of stimuli to the corresponding position on the opposite side of the body or hemispace. It is most often, although not exclusively, reported in the tactile modality and typically in association with unilateral neglect. We describe a patient presenting with a 2-year history of topographical disorientation without other cognitive complaints. We conducted a systematic exploration of his topographical problems to identify their cognitive substrate. Standard neuropsychological examination revealed no abnormalities. Notably, he performed well on perceptual, spatial, and constructional tasks. No signs of neglect were elicited. A tailored battery of tests was administered, involving road maps and landmarks, and designed to replicate the situations in which he experienced symptoms. The experimental tests showed no evidence of topographical agnosia or amnesia for landmarks and their spatial relationships and no hemispatial neglect. Nevertheless, the patient exhibited a systematic tendency to translocate topographical landmarks sited on the left to the right side. The phenomenon, consistent with representational allochiria, occurred exclusively for topographical landmarks, and was present along both personally familiar and new learned routes. Over the next two years more widespread visuoperceptual and spatial deficits emerged, with Balint and Gerstmann syndromes. Functional imaging revealed hypoperfusion of the occipito-parietal regions and amyloid PET the presence of amyloid plaques. A diagnosis was made of posterior cortical atrophy, the visual variant of Alzheimer's Disease. To our knowledge this is the first case of topographical disorientation presenting with selective representational allochiria and the first report of allochiria as an early sign of posterior cortical atrophy. The case sheds light on the cognitive basis of allochiria and on a puzzling clinical presentation of neurodegenerative brain disease.

Diagnostic Accuracy of Affective Social Tasks in the Clinical Classification Between the Behavioral Variant of Frontotemporal Dementia and Other Neurodegenerative Disease.

BACKGROUND: Severe socio-emotional impairments characterize the behavioral variant of frontotemporal dementia (bvFTD). However, literature reports social cognition disorders in other dementias. OBJECTIVE: In this study, we investigated the accuracy of social cognition performances in the early and differential diagnosis of bvFTD. METHODS: We included 131 subjects: 32 bvFTD, 26 Alzheimer's disease (AD), 16 primary progressive aphasia (PPA), 17 corticobasal syndrome (CBS), and 40 healthy control (HC). Each subject completed the Ekman 60 faces (Ek-60F) test assessing basic emotion recognition and the Story-based Empathy Task (SET) assessing attribution of intentions/emotions. A combined social measure (i.e., Emotion Recognition and Attribution (ERA) index) was calculated. One-way ANOVA has been used to compare performances among groups, while receiver operating characteristic (ROC) curve tested measures ability to distinguish subjects with and without bvFTD. RESULTS: Ek-60F and ERA index scores were significantly lower in bvFTD versus HC, AD, and PPA groups. ROC analyses significantly distinguished bvFTD from HC (AUC 0.82-0.92), with the Ek-60F test showing the highest performance, followed by the ERA index. These two social measures showed the best accuracy in detecting bvFTD from AD (AUC 0.78-0.74) and PPA (AUC 0.80-0.76). Investigated measures failed in detecting bvFTD from CBS. CONCLUSION: Accuracy analyses support the advantage of using social cognition tests for bvFTD diagnosis. Short social battery may reduce uncertainties and improve disease identification in clinical settings. We recommend a revision of current clinical criteria considering neuropsychological deficits in emotion recognition and processing tasks as key cognitive markers of this neurodegenerative syndrome.

The neural bases of discourse semantic and pragmatic deficits in patients with frontotemporal dementia and Alzheimer's disease.

Neuropsychological research on language has largely focused on how the brain processes single words and sentences whose meaning does not depend on the context or on the intentions of the speaker. Fewer studies have investigated the neurobiological bases of discourse semantics and pragmatics in patients and healthy individuals. We studied discourse semantic and pragmatic skills in patients with behavioral variant frontotemporal dementia (bvFTD) or Alzheimer's disease (AD) in comparison to healthy controls. Our goal was to assess whether and how the two patient groups differ in their cognitive and behavioral profiles, and whether these differences may be traced back to disease-specific patterns of neuronal hypometabolism. We combined PET imaging with standard neuropsychological assessment tools and a dedicated test battery designed to evaluate discourse semantics and pragmatics in patients with brain lesions or neurological disorders. We found that AD and bvFTD patients were both impaired compared to controls in discourse comprehension, but largely spared in single word comprehension. Importantly, we also found evidence for behavioral impairments specific to each disease, associated with different brain damage patterns. Compared to AD and controls, bvFTD patients had, behaviorally, more difficulty in evaluating whether certain inferences follow from discourse and in identifying humorous completions of stories; neurally, they had greater damage to medial and lateral regions of PFC. AD patients showed a different pattern of errors in a humor comprehension task than bvFTD patients and controls, and they showed greater posterior temporal and parietal cortical depletion. Both groups had comparable difficulties with understanding idioms and indirect requests. Finally, bvFTD-specific errors were correlated with the severity of hypometabolism in bvFTD. We discuss these results in light of previous research on the dementias as well as consequences for models of semantics and pragmatics in the brain.

Insight in frontotemporal dementia and progressive supranuclear palsy.

INTRODUCTION: Progressive supranuclear palsy (PSP) and behavioural variant frontotemporal dementia - (bv-FTD) share common neuropsychological features except for online monitoring awareness. Therefore, the aim of our study is to explore if this assessment could be used in standard clinical practice. MATERIALS AND METHODS: We retrospectively analyse 93 subjects (27 FTD, 25 PSP, 42 healthy controls). Neuropsychological and instrumental examinations were performed for each patient. RESULTS: FTD patients made fewer self-corrections than PSP patients despite a similar number of total errors. We also performed ROC curves: the area under the curve (AUC) is 0.79. A model for a logistic regression was also developed: the only significant predictor is the number of self-corrections (p = 0.004 ß = 1244). DISCUSSION AND CONCLUSIONS: In conclusion, our findings show online awareness is more compromised in FTD patients than in PSP patients. This difference could be useful for making a differential diagnosis between the two diseases: for each extra point in number of self-corrections the probability of suffering from PSP increases by about three and a half times (OR 3.47).

Inter-rater reliability of primitive signs in dementia.

OBJECTIVES: The aim of the present study is to explore inter-rater reliability of primitive signs in a group of patients assessed for dementia. PATIENTS AND METHODS: 97 patients admitted to our University Hospital for cognitive impairment were enrolled in the study. The mean age was 73.04 ±â€¯8.68 (53 females and 44 males). All patients were examined by two cognitive neurologists in a blind fashion. The grasp reflex, the snout reflex, the glabella tap reflex and the palmomental reflex were elicited according to the current literature. Moreover, we add a stretch reflexes (the masseter reflex) to our battery. RESULTS: The most frequent primitive reflex was the palmomental reflex followed by the glabella tap, snout, and grasp. The inter-rater reliability was measured for each primitive reflex: grasp reflex (0.884) have a strong correspondence; the glabella tap (0.556), the palmomental (0.516) and the snout reflex (0.445) have otherwise a weak correspondence. The masseter reflex reaches a moderate agreement (0.662). All the measurements reached statistical significance (p < 0.005). CONCLUSION: The results of the study show weak to substantial agreement for primitive signs and the masseter reflex as expressed by the low-to-high kappa values.

Famous faces and voices: Differential profiles in early right and left semantic dementia and in Alzheimer's disease.

BACKGROUND: Famous face and voice recognition is reported to be impaired both in semantic dementia (SD) and in Alzheimer's Disease (AD), although more severely in the former. In AD a coexistence of perceptual impairment in face and voice processing has also been reported and this could contribute to the altered performance in complex semantic tasks. On the other hand, in SD both face and voice recognition disorders could be related to the prevalence of atrophy in the right temporal lobe (RTL). OBJECTIVE: The aim of the present study was twofold: (1) to investigate famous faces and voices recognition in SD and AD to verify if the two diseases show a differential pattern of impairment, resulting from disruption of different cognitive mechanisms; (2) to check if face and voice recognition disorders prevail in patients with atrophy mainly affecting the RTL. MATERIALS: To avoid the potential influence of primary perceptual problems in face and voice recognition, a pool of patients suffering from early SD and AD were administered a detailed set of tests exploring face and voice perception. Thirteen SD (8 with prevalence of right and 5 with prevalence of left temporal atrophy) and 25 CE patients, who did not show visual and auditory perceptual impairment, were finally selected and were administered an experimental battery exploring famous face and voice recognition and naming. Twelve SD patients underwent cerebral PET imaging and were classified in right and left SD according to the onset modality and to the prevalent decrease in FDG uptake in right or left temporal lobe respectively. Correlation of PET imaging and famous face and voice recognition was performed. RESULTS: Results showed a differential performance profile in the two diseases, because AD patients were significantly impaired in the naming tests, but showed preserved recognition, whereas SD patients were profoundly impaired both in naming and in recognition of famous faces and voices. Furthermore, face and voice recognition disorders prevailed in SD patients with RTL atrophy, who also showed a conceptual impairment on the Pyramids and Palm Trees test more important in the pictorial than in the verbal modality. Finally, in 12SD patients in whom PET was available, a strong correlation between FDG uptake and face-to-name and voice-to-name matching data was found in the right but not in the left temporal lobe. DISCUSSION: The data support the hypothesis of a different cognitive basis for impairment of face and voice recognition in the two dementias and suggest that the pattern of impairment in SD may be due to a loss of semantic representations, while a defect of semantic control, with impaired naming and preserved recognition might be hypothesized in AD. Furthermore, the correlation between face and voice recognition disorders and RTL damage are consistent with the hypothesis assuming that in the RTL person-specific knowledge may be mainly based upon non-verbal representations.