Analysis of word comprehension in a case of pure word deafness

A case of pure word deafness due to a left temporal infarct is reported. The results of dichotic tests suggest that auditory verbal material may be processed in the right hemisphere. The inability to repeat nonsense words, the frequent semantic paraphasias in real-word repetition tasks, and the capacity to give a partial account of the meaning of a word that the patient cannot repeat show that despite the impairment of the phonological analysis, lexical semantic processing is possible. An attempt is made to demonstrate that the patient resorts to this semantic processing and that this reflects the linguistic competence of the right hemisphere.     

Jargonagraphia in a case of frontotemporal dementia.

Jargonagraphia is known to occur after discrete brain lesions but not in primary degenerative dementia. We report a patient with frontotemporal dementia who developed jargonagraphia and nonfluent aphasia. Written output was graphically preserved but consisted of short words intermingled with abstruse neologisms. MRI showed predominant right frontotemporal cortical atrophy accompanied by white matter hyperintensities in the right anterior subcallosal periventricular region. Diagnosis and MRI were corroborated by extensive neuropathological findings obtained 8 months later. The agraphia in this case is discussed with reference to both specific macroscopic and microscopic pathoanatomical lesions. We suggest that jargonagraphia can appear in frontotemporal dementia depending on the localization of lesions.     

Deficit of preparatory attention in frontotemporal dementia

We studied preparatory attention in patients suffering from frontotemporal dementia in the beginning stages of the disease, using an experimental test developed by LaBerge, Auclair, and Siéroff (2000). In this experimental test, a distracter can appear while subjects have to prepare to respond to a simple target. The probability that a distracter can appear in a trial is varied across three blocks. Normal controls show an increase of response times to targets (slope) as a function of the distracter probability, preparatory attention to the target is reduced by the increase of the distracter probability. Patients suffering from frontotemporal dementia show a slope of response times which is more than twice as large as the slope obtained by their matched controls. Such an abnormal increase of response times to targets is interpreted as a deficit in preparatory attention. Patients also show more omissions than controls. We suggest that this deficit in preparatory attention is related to the frontal lesion presented by the patients and can result in higher distractibility, a symptom frequently encountered in these patients.     

Divergent thinking in Alzheimer's and frontotemporal dementia

Twenty-three patients with mild dementia of the Alzheimer's type (DAT) or frontotemporal type (DFT) and age- and education-matched control subjects were administered tests of complex fluency involving divergent thinking and tests of letter, category, and figural fluency. The tests of complex fluency discriminated the dementia patients from control subjects more strongly than did the other fluency tests. The results suggest that divergent thinking as assessed by complex fluency tests is a cognitive domain that is impaired early in the course of dementia. The sensitivity of complex fluency tests compared to that of letter, category, and figural fluency tests may be related to greater demands for conceptualization in relating stimulus attributes to function and greater demands for flexible thinking during self-directed search processes.     

False recognition in Lewy-body disease and frontotemporal dementia

The primary goal of this study was to evaluate the false recognition phenomenon in persons with frontotemporal dementia (FTD) and those with Lewy-body disease (LBD). Patients with LBD (n=10) or FTD (n=15) and their corresponding controls (n=30) were subjected to the Deese-Roediger-McDermott (DRM) paradigm to induce false recognition. Patients were first presented with items semantically related to a nonpresented critical target. The critical target was later included in a word list shown to patients to assess level of recognition. Both groups of patients showed a reduced level of false recognition of the critical target when controlling for their overall level of false alarms. This reduction was greater in persons with LBD than in those with FTD. Correlational analyses of performance on neuropsychological tests and the DRM variables indicated that the reduced DRM effect was associated with inhibition deficits in patients with LBD and with inhibition deficits and verbal memory in those with FTD. Our results support current models suggesting that these cognitive components contribute to the false recognition effect.     

An analysis of speech perception in word deafness

A patient with a rather pure word deafness showed extreme suppression of right ear signals under dichotic conditions, suggesting that speech signals were being processed in the right hemisphere. Systematic errors in the identification and discrimination of natural and synthetic stop consonants further indicated that speech sounds were not being processed in the normal manner. Auditory comprehension improved considerably however, when the range of speech stimuli was limited by contextual constraints. Possible implications for the mechanism of word deafness are discussed.     

Problems inhibiting attentional capture by irrelevant stimuli in patients with frontotemporal dementia

We studied the role of the frontal lobes in orienting spatial attention and inhibiting attentional capture by goal-irrelevant stimuli, using a spatial cueing method in patients with frontotemporal dementia (FTD). Two blocks of trials were presented, one with non-predictive cues and the other with counter-predictive cues. FTD patients showed a global orienting deficit, with a greater difference between invalid and valid trials than age-matched controls. However, they were able to use the (counter-) predictiveness of the cue to reduce the invalid/valid difference when targets occurred most often in the location opposite the cue. Thus, endogenous control of attention in our FTD patients was sufficient to reorient attention on the basis of the probability of events, but not to resist the capture of attention by goal-irrelevant stimuli. These results confirm the role of frontal lobes in the inhibition of attentional capture.     

Using music to decrease disruptive vocalizations in a man with dementia

Music played through headphones was noted to reduce the disruptive chanting and speech‐like vocalizations of a 68‐year‐old man who lived in a secure dementia unit. We conducted a variety of assessment procedures, including a functional analysis ‘alone’ condition, to identify why this simple intervention may have been effective for this individual. The data suggest that music provided an alternative source of auditory stimulation to that produced by automatically reinforced vocal behavior. Copyright © 2010 John Wiley & Sons, Ltd.     

From narcissistic personality disorder to frontotemporal dementia: a case report

Premorbid personality characteristics could have a pathoplastic effect on behavioral symptoms and personality changes related to neurodegenerative diseases. Patients with personality disorders, in particular of the dramatic cluster, may present functional frontolimbic abnormalities. May these neurobiological vulnerabilities linked to a premorbid personality disorder predispose or represent a risk factor to subsequently develop a neurodegenerative disorder? Are subjects with personality disorders more at risk to develop a dementia than mentally healthy subjects? This topic is discussed presenting the clinical case of a patient who suffered of a probable Narcissistic Personality Disorder and subsequently developed a clinically diagnosed Frontotemporal Dementia.     

Insight in frontotemporal dementia: conceptual analysis and empirical evaluation of the consensus criterion "loss of insight" in frontotemporal dementia

The objective of this study was to suggest a new formulation of the core research diagnostic consensus criterion "loss of insight" in frontotemporal dementia (FTD). Eight patients with FTD (diagnoses made by interviews, medical and neuropsychological examination, CT scan, and regional cerebral glucose metabolism measured by positron emission tomography (PET) participated in the study). The results indicated that insight was present in three out of eight patients, and that insight appears to be a heterogeneous concept. Two types of insight emerged: Emotional insight associated with frontotemporal functions, and cognitive insight, related to posterior cognitive functions. These results suggest that loss of insight should not serve as a core criterion on FTD, but serves well as a supportive criterion of the disease.     

Apathy in frontotemporal dementia: behavioral and neuroimaging correlates

We investigated the occurrence of goal-directed motivational change in the form of apathy in patients with frontotemporal dementia (FTD), particularly those with behavioral variant social and executive deficits (bvFTD). Standardized behavioral inventory was employed to survey and compare apathy ratings from patients and caregivers. In cases of bvFTD, apathy ratings were further related to measures of social cognition, executive function, and atrophy on brain MRI. Results indicated that caregivers rated bvFTD patients as having significantly elevated apathy scores though patient self-ratings were normal. Caregiver and self-ratings of FTD samples with progressive nonfluent aphasia and semantic dementia did not differ from healthy controls and their informants. In the bvFTD sample, caregiver apathy scores were not correlated with general cognitive screening or depression scores, but were significantly correlated with social cognition and executive function measures. Voxel-based morphometry revealed that apathy ratings in bvFTD were related to prominent atrophy in the right caudate (including the ventral striatum), the right temporo-parietal junction, right posterior inferior and middle temporal gyri, and left frontal operculum- anterior insula region. Findings suggest that bvFTD is associated with a significant breakdown in goal-directed motivated behavior involving disruption of cortical-basal ganglia circuits that is also related to social and executive function deficits.     

Neural basis for sentence comprehension deficits in frontotemporal dementia

Many patients with frontotemporal dementia (FTD) have impaired sentence comprehension. However, the pattern of comprehension difficulty appears to vary depending on the clinical subgroup. The purpose of this study was to elucidate the neural basis for these deficits in FTD. We studied patients with two different presentations: Three patients with Progressive Non-Fluent Ahasia (PNFA), and five non-aphasic patients with a dysexecutive and social impairment (EXEC). The FTD patient subgroups were compared to a cohort of 11 healthy seniors with intact sentence comprehension. We monitored regional cerebral activity with blood oxygen level dependent (BOLD) functional magnetic resonance imaging (fMRI) while subjects read sentences featuring both a grammatically complex object-relative center-embedded clause and a long linkage between the head noun phrase (NP) and the gap where the NP is interpreted in the center-embedded clause. Subjects decided whether the agent of the action is a male or a female. Healthy seniors activated both ventral portions of inferior frontal cortex (vIFC) and dorsal portions of IFC (dIFC) in the left hemisphere, often associated with grammatical and working memory components of these sentences, respectively. PNFA patients differed from healthy controls since they have reduced activation of left vIFC, while EXEC patients have less recruitment of left dIFC. We conclude that FTD subgroups have distinct patterns of sentence comprehension difficulty in part because of selective interruptions of a large-scale neural network for sentence processing.     

Speech discrimination and lip reading in patients with word deafness or auditory agnosia

The purpose of this study was to assess the ability of four patients with word deafness or auditory agnosia to discriminate speech by reading lips. The patients were studied using nonsense monosyllables to test for speech discrimination, a lip reading test, the Token Test for auditory comprehension, and the Aphasia test. Our results show that patients with word deafness or auditory agnosia without aphasia can improve speech comprehension by reading lips in combination with listening, as compared with lip reading or listening alone. In conclusion, lip reading was shown to be useful for speech comprehension among these patients.     

Disorder in sequential speech perception: a case study on pure word deafness

We described disorders of a patient which were uniquely restricted to speech perception of syllable sequences after brain damage. The results of series of experiments using syllable sequences showed "negative recency effect," in which the subject's repetition performance at the latter syllable position was remarkably poor. Experimental analyses suggested that the "negative recency effect" could be due to dual factors: the lower rate of processing of speech sounds and the memory load of holding processes of preceding syllables imposed on the succeeding phonological processing. The results also suggested that the holding processes which imposed the memory load on the succeeding auditory phonological coding processing were modality nonspecific.     

Distinct performance profiles on the Brixton test in frontotemporal dementia

The Brixton Spatial Anticipation Test is a well-established test of executive function that evaluates the capacity to abstract, follow, and switch rules. There has been remarkably little systematic analysis of Brixton test performance in the prototypical neurodegenerative disorder of the frontal lobes: behavioural variant frontotemporal dementia (bvFTD) or evaluation of the test’s ability to distinguish frontal from temporal lobe degenerative disease. We carried out a quantitative and qualitative analysis of Brixton performance in 76 patients with bvFTD and 34 with semantic dementia (SD) associated with temporal lobe degeneration. The groups were matched for demographic variables and illness duration. The bvFTD group performed significantly more poorly (U = 348, p < .0001, r = .58), 53% of patients scoring in the poor–impaired range compared with 6% of SD patients. Whereas bvFTD patients showed problems in rule acquisition and switching, SD patients did not, despite their impaired conceptual knowledge. Error analysis revealed more frequent perseverative errors in bvFTD, particularly responses unconnected to the stimulus, as well as random responses. Stimulus-bound errors were rare. Within the bvFTD group, there was variation in performance profile, which could not be explained by demographic, neurological, or genetic factors. The findings demonstrate sensitivity and specificity of the Brixton test in identifying frontal lobe degenerative disease and highlight the clinical value of qualitative analysis of test performance. From a theoretical perspective, the findings provide evidence that semantic knowledge and the capacity to acquire rules are dissociable. Moreover, they exemplify the separable functional contributions to executive performance.     

The spectrum of recurrent thoughts and behaviors in frontotemporal dementia

This article describes the spectrum of recurrent thoughts and behaviors that can result from frontotemporal dementia (FTD) and its variants. Although repetitive behaviors can result from a range of brain disorders, FTD is the most common neurologic cause of new-onset recurrent thoughts and behaviors in middle or late life. Patients with FTD can manifest typical or bizarre compulsions, hoarding, verbal and motor stereotypies and complex tics; self-injurious acts, perseverations; and fixed, obsessional thoughts. The frequency and variability of these repetitive behaviors suggest a common disturbance of orbitofrontal-basal ganglia circuits involved in response inhibition. The amelioration of these recurrent events with the administration of serotonin selective reuptake inhibitors further suggests a serotonergic deficit.     

Enhancing theory of mind in behavioural variant frontotemporal dementia with transcranial direct current stimulation

Behavioural variant frontotemporal dementia (bvFTD) is a form of frontotemporal degeneration characterized by early changes in personality, emotional blunting, and/or loss of empathy. Recent research has highlighted that these features may be at least partially explained by impairments in the theory of mind (ToM; i.e., the ability to understand and predict other people’s behaviour by attributing independent mental states to them). The aim of this randomized, double-blind, placebo-controlled study was to test the hypothesis that transcranial direct current stimulation (tDCS) over the medial frontal cortex (MFC) selectively enhances communicative intention processing, a specific ToM ability. Using a single-session online design, we administered a ToM task that measures the ability to represent other people’s private and communicative intentions during active or sham tDCS to 16 bvFTD patients. To assess the impact of dementia on performance on the ToM task, we included 16 age-matched healthy volunteers who were asked to perform the entire experimental ToM task. BvFTD is characterized by an impairment in the comprehension of both communicative and private intentions relative to a healthy control group and by a disproportional impairment in communicative intention compared with private intention processing. Significant and selective accuracy improvement in the comprehension of communicative intentions after active stimulation was observed in patients with bvFTD. This is the first study that analyses ToM ability in patients with bvFTD using tDCS stimulation. Our findings could potentially contribute to the development of an effective, noninvasive brain stimulation treatment of ToM impairments in patients with bvFTD.     

Evidence for a parallel input serial analysis model of word processing

A parallel input serial analysis (PISA) model of word processing was developed and tested. The goal was to expand on the "critical processing duration" hypothesis of Johnson, Allen, and Strand (1989) so that both single-word and multiple-word presentation, letter detection data could be explained. In Experiments 1-3 four different word frequency categories on a single-presentation, letter detection task were used. These three experiments indicated that there was a curvilinear relationship between word frequency and letter detection reaction time (RT). That is, letter detection RTs for medium-high-frequency words were significantly longer than letter detection RTs for very-high-, low-, and very-low-frequency words. These results support the PISA model rather than the Healy, Oliver, and McNamara (1987) version of the unitization model. In Experiments 4-5 multiple-presentation (i.e., two words), letter detection tasks were used. The PISA model could also account for the results from these two experiments, but the unitization model could not.     

Writing program with word prediction for a young man with multiple disabilities: a preliminary assessment

This study assessed a writing program with word prediction, which completed the writing of a word and spoke it out only when there was certainty that such a word was the correct one. The assessment was carried out with a young man with multiple disabilities, who typically used a word-processing program without word prediction. The two programs were compared on the time required by the participant for writing general sentences, through a social validation assessment, and eventually a check on the participant's preference. Analysis showed the program with word prediction was significantly more effective in terms of the writing time, which was halved, and was deemed preferable by 40 raters (psychology students) involved in the social validation assessment and by the participant himself. Implications of the findings are discussed.