Preserved calculation skills in a case of semantic dementia

We present the case of a patient, BET, with a profound semantic dementia who shows a selective preservation of many aspects of number knowledge. In the context of an otherwise global loss of visual and verbal semantic knowledge, our patient demonstrates relatively intact number processing and numerical calculation in both the verbal and visual domain. More remarkably, BET is able to harness her intact calculation skills to number problem solving tasks. Our report provides further evidence that high-level non-verbal reasoning may persist in the absence of any viable language skills.     

语义性痴呆的临床、认知和影像学特征研究-附3例报告

目的 分析语义性痴呆(semantic dementia，SD)患者的临床、认知缺损与保持模式和影像学特征。方法 针对3例SD患者完成详细的病史采集、一系列神经心理测验和头颅核磁共振(MR)检查。结果 SD的临床特点是起病年龄相对较轻、以命名障碍为最早最严重的症状、应用乙酰胆碱酯酶抑制剂治疗有较明显的不良反应。SD的认知特点是呈现语义记忆的选择性损害、物品命名、列举某一范畴的例子、词语的阅读理解和语义相似性判断等项目严重受损；情景记忆、空间知觉、执行功能和非言语的解决问题能力相对正常。SD的影像学特点是在冠状位MR摄片上呈现左颞叶新皮层局限性严重萎缩。结论 SD患者具有独特的临床、认知和影像学特征。     

How Berlusconi keeps his face: a neuropsychological study in a case of semantic dementia

A patient (V.Z.) is described as being affected by progressive bilateral atrophy of the mesial temporal lobes resulting in semantic dementia. Vis-a-vis virtually nil recognition of even the most familiar faces (including those of her closest relatives) as well as of objects and animals, V.Z. could nevertheless consistently recognize and name the face of Silvio Berlusconi, the mass media tycoon and current Italian Prime Minister. The experimental investigation led to the conclusion that Mr Berlusconi's face was seen as an icon rather than as a face. This telling effect of Mr Berlusconi's pervasive propaganda constitutes an unprecedented case in the neuropsychological literature.     

Restoration of conceptual knowledge in a case of semantic dementia

Patients with semantic dementia (SD) may undergo successful relearning of object names, but these gains are usually restricted to the trained exemplars, demonstrating poor generalization. We hypothesized that generalization could be improved by restoring an item’s semantic network through specific strategies that recruit the remaining personal semantic memories (conceptual enrichment therapies). We describe the case of a patient with SD who showed greater generalization of learning following a conceptual enrichment therapy than when learning items in a word-retrieval therapy. Our results suggest that enhancing an item’s semantic network connections may result in improved generalization of learning in SD. A learning mechanism in the presence of compromised hippocampi is also discussed.     

Autobiographical memory in semantic dementia: A longitudinal fMRI study

Whilst patients with semantic dementia (SD) are known to suffer from semantic memory and language impairments, there is less agreement about whether memory for personal everyday experiences, autobiographical memory, is compromised. In healthy individuals, functional MRI (fMRI) has helped to delineate a consistent and distributed brain network associated with autobiographical recollection. Here we examined how the progression of SD affected the brain's autobiographical memory network over time. We did this by testing autobiographical memory recall in a SD patient, AM, with fMRI on three occasions, each one year apart, during the course of his disease. At the outset, his autobiographical memory was intact. This was followed by a gradual loss in recollective quality that collapsed only late in the course of the disease. There was no evidence of a temporal gradient. Initially, AM's recollection was supported by the classic autobiographical memory network, including atrophied tissue in hippocampus and temporal neocortex. This was subsequently augmented by up-regulation of other parts of the memory system, namely ventromedial and ventrolateral prefrontal cortex, right lateral temporal cortex, and precuneus. A final step-change in the areas engaged and the quality of recollection then preceded the collapse of autobiographical memory. Our findings inform theoretical debates about the role of the hippocampus and neocortical areas in supporting remote autobiographical memories. Furthermore, our results suggest it may be possible to define specific stages in SD-related memory decline, and that fMRI could complement MRI and neuropsychological measures in providing more precise prognostic and rehabilitative information for clinicians and carers.     

弥散张量成像在词义性痴呆中的应用：个案研究

语义性痴呆 (SD) 是原发性进行性失语的罕见类型,以获得性的命名和理解障碍为特征,很少伴有语言节律和语法的异常,在疾病早期可能有认知功能的损害。 目的: 研究一例中国语义性痴呆患者大脑的局灶性异常。方法: 研究将一例语义性痴呆的患者与21例正常老年对照进行比较,采用弥散张量成像 (DTI) 来测定平均弥散度系数(MD)和部分各向异性(FA)值,并将所有的弥散度和各向异性通过统计学参数图法 (SPM)进行基于体素的分析 (VBA) 。结果：患者双侧大脑的平均弥散系数较对照组明显增加,以左侧明显,并且扩散至语言功能环路以外的脑区,未发现存在MD 降低的脑区。同时,患者胼胝体的FA 值较对照组存在明显降低,在双侧基底节区域则明显增加。结论：语义性痴呆患者的大脑弥散存在明显改变,比常规异常脑区更为广泛。MD比 FA 更加敏感,提示 MD 可能作为疾病程度检测的一项重要影像学指标。     

Suicide as a result of stereotypic behaviour in a case with semantic dementia

Semantic dementia (SD) is characterized by semantic aphasia and prosopagnosia, but it may also include behavioural disturbances such as stereotypic behaviour. We report the case of a 50‐year‐old man with SD accompanied by stereotypic behaviour who committed suicide despite not being in a depressive state. He initially had major depressive disorder accompanied by suicide attempts, but he gradually showed remarkable impairment in single‐word semantic comprehension, naming memory, and facial recognition memory. After the diagnosis of SD, his suicidal behaviour by hanging with a cord became stereotypic and lacked seriousness. He repeatedly attempted to hang himself and finally completed suicide. The present report suggests that the risk for suicide in SD is increased not only by the presence of a depressive state, but also by stereotypic behaviour related to suicide attempts before the onset of the disorder.     

Cerebral perfusion patterns in vascular dementia of Binswanger type compared with senile dementia of Alzheimer type: a SPECT study

Summary Cerebral perfusion patterns in 18 cases with vascular dementia of Binswanger type (VDBT) (8 moderate and 10 severe cases) were compared with 25 cases with senile dementia of Alzheimer type (SDAT) (16 moderate and 9 severe cases) and 14 controls by single photon emission computed tomography usingN-isopropyl-p-¹²³I iodoamphetamine (IMP) as a tracer. The cerebral: cerebellar IMP uptake ratio (%) (CCR) was used as a measure of relative cerebral perfusion. The CCRs were about 85–90% in all areas in controls. Moderate VDBT patients showed a remarkable decrease of CCRs in the basal grey region (thalamus and basal ganglia) (right 79%, left 77%) and in the frontal area (right 79%, left 80%) (P<0.01). In severe VDBT patients a significant decrease of the CCR was noted in all regions (P<0.01). The decrease of mean CCRs in the hemispheres was significantly correlated with the severity of disease determined by psychometric testing. Patients with SDAT showed a significant decrease of the CCR in the parietal (right 71%, left 74%) and right temporal (78%) areas in the moderate stage (P<0.01), and further progression of dementia was associated with low perfusion areas extending to the frontal areas (78%,P<0.01). These differences in the perfusion patterns and their changes with progression of the illnesses may be reflected in characteristic clinical features.     

Atypical non-progressive semantic impairment following allogeneic bone marrow transplantation in a patient with Waldenström’s macroglobulinemia: A case report

Objective: A case report of a 74-year-old male presenting with an atypical multimodal semantic impairment. The patient was diagnosed with Waldenström macroglobulinemia (WM) for which he received allogeneic bone marrow transplantation (BMT) due to disease progression. Following BMT, he developed a sudden onset of semantic difficulties that have remained unchanged for eight years. No other cognitive functions have been affected and his activities of daily living remain fully preserved.

Method: The patient was assessed at our neuropsychology unit with six neuropsychological evaluations over an 8-years follow-up period following BMT. Additional semantic tests were administered during the last three evaluations. Four MRI scans (at age 62, 66, 69 and 74) and 18F-FDG PET (at age 74) were obtained.

Results: The patient presents a multimodal semantic impairment, including naming impairment, visual agnosia, prosopoanomia, associative prosopagnosia, topographical disorientation and impaired retrograde memory for public events. MRI scans and 18F-FDG PET revealed bilateral symmetrical atrophy (temporal?>?frontal) and inferior bilateral temporal lobe hypometabolism, respectively. Neuroradiological examination was unremarkable prior to BMT.

Conclusion: Clinical diagnosis remains a challenge given the focal and stable nature of his deficits. We hypothesize that the BMT procedure might have resulted in the temporal lobe damage and subsequent semantic impairment. We recommend obtaining a thorough neuropsychological evaluation of patients who receive allogenic BMT, both prior to and following transplant.     

A combined neuropsychological and neuroimaging study of topographical and non-verbal memory in semantic dementia

A combined neuropsychological and neuroimaging investigation was carried out on a patient (O.I.) with semantic dementia who had asymmetrical temporal lobe atrophy, greater on the left. His performance on tests of verbal memory was gravely impaired. Similarly, his visual memory as indexed by recognition of unfamiliar faces was impaired. By contrast, his recognition memory for topographical memoranda (e.g. buildings, landscapes) and ability to find his way around was preserved. In order to identify the neural substrates supporting the preserved recognition of static topographical memoranda, O.I. was scanned using positron emission tomography (PET) during the encoding and recognition of building and landscape stimuli. In common with control subjects, during encoding O.I. activated parahippocampal cortex bilaterally, along with bilateral temporo-parietal, retrosplenial and left frontal cortices. During recognition, both patient and controls activated right parahippocampal, right superior parietal and right frontal cortices. Notably, control subjects, but not O.I., also activated at encoding the precuneus and at recognition the retrosplenial cortex. This allows the conclusion that these two areas while involved may not be necessary for topographical memory. Interestingly, the patient also activated regions that were not evident in control subjects both during encoding and recognition. These additional areas of activation may be necessary in a compensatory role. Overall, these data represent the first reported assessment of the functional integrity of degenerating brain tissue and its contribution to preserved topographical memory. The combination of the neuropsychological and neuroimaging approaches may provide insights into the functional-anatomy of memory while having clinical utility for the assessment of residual brain tissue.     

Distinct neural substrates of affective and cognitive theory of mind impairment in semantic dementia

Using structural MRI, we investigated the brain substrates of both affective and cognitive theory of mind (ToM) in 19 patients with semantic dementia. We also ran intrinsic connectivity analyses to identify the networks to which the substrates belong and whether they are functionally disturbed in semantic dementia. In line with previous studies, we observed a ToM impairment in patients with semantic dementia even when semantic memory was regressed out. Our results also highlighted different neural bases according to the nature (affective or cognitive) of the representations being inferred. The affective ToM deficit was associated with atrophy in the amygdala, suggesting the involvement of emotion-processing deficits in this impairment. By contrast, cognitive ToM performances were correlated with the volume of medial prefrontal and parietal regions, as well as the right frontal operculum. Intrinsic connectivity analyses revealed decreased functional connectivity, mainly between midline cortical regions and temporal regions. They also showed that left medial temporal regions were functionally isolated, a further possible hindrance to normal social cognitive functioning in semantic dementia. Overall, this study addressed for the first time the neuroanatomical substrates of both cognitive and affective ToM disruption in semantic dementia, highlighting disturbed connectivity within the networks that sustain these abilities.     

Changes in local brain function in mild cognitive impairment due to semantic dementia

AimsMild cognitive impairment due to semantic dementia represents the preclinical stage, involving cognitive decline dominated by semantic impairment below the semantic dementia standard. Therefore, studying mild cognitive impairment due to semantic dementia may identify changes in patients before progression to dementia. However, whether changes in local functional activity occur in preclinical stages of semantic dementia remains unknown. Here, we explored local functional changes in patients with mild cognitive impairment due to semantic dementia using resting‐state functional MRI.MethodsWe administered a battery of neuropsychological tests to twenty‐two patients with mild cognitive impairment due to semantic dementia (MCI‐SD group) and nineteen healthy controls (HC group). We performed structural MRI to compare gray matter volumes, and resting‐state functional MRI with multiple sub‐bands and indicators to evaluate functional activity.ResultsNeuropsychological tests revealed a significant decline in semantic performance in the MCI‐SD group, but no decline in other cognitive domains. Resting‐state functional MRI revealed local functional changes in multiple brain regions in the MCI‐SD group, distributed in different sub‐bands and indicators. In the normal band, local functional changes were only in the gray matter atrophic area. In the other sub‐bands, more regions with local functional changes outside atrophic areas were found across various indicators. Among these, the degree centrality of the left precuneus in the MCI‐SD group was positively correlated with general semantic tasks (oral sound naming, word‐picture verification).ConclusionOur study revealed local functional changes in mild cognitive impairment due to semantic dementia, some of which were located outside the atrophic gray matter. Driven by functional connectivity changes, the left precuneus might play a role in preclinical semantic dementia. The study proved the value of frequency‐dependent sub‐bands, especially the slow‐2 and slow‐3 sub‐bands.     

Brain activation during semantic judgment of Chinese sentences: A functional MRI study

A functional magnetic resonance imaging (fMRI) study was conducted to investigate whether the anatomic substrates of semantic memory may reflect categorical organization and to determine whether the left middle frontal gyrus (Brodmann area [BA] 9) plays a role in Chinese semantic judgment. Unlike previous studies using a word-retrieval task (e.g., word generation, naming, and word categorization), we used a typical task of semantic knowledge retrieval in cognitive psychology in which subjects were asked to determine whether a sentence describing an attribute of living things or nonliving things was true or not. The experimental conditions evoked extensive activation over several regions of the brain including a very strong activation in the left middle frontal region (BA9 and BA46). Our data show that there is no unique activation associated with living or nonliving things at the statistical threshold used in our study. The results imply that human semantic system is undifferentiated by category at the neural level. Our findings also corroborate and extend the claim that the left middle frontal gyrus plays an important role in reading Chinese at both the sentence and the word level.     

Oxiracetam in dementia: a double-blind, placebo-controlled study

A multicentre, double-blind, between-patient study was carried out to evaluate the efficacy and tolerability of oxiracetam (800 mg tablet), in comparison with placebo, each given twice daily for 12 weeks to patients suffering from primary degenerative, multi-infarct or mixed dementia. Efficacy was assessed by a neuropsychological battery (simple reaction time, controlled associations, short story, Raven's Progressive Matrices, token test, digit span, word list learning), administered at the beginning and at the end of the study, and by a quality of life scale, administered at entry and after 6 and 12 weeks treatment. Sixty-five patients (28 men, 37 women, mean age 71 yrs) were enrolled; 58 completed the study: 2 on oxiracetam were withdrawn because of poor tolerability, 2 (one in each group) were withdrawn for poor compliance, one (on oxiracetam) for the occurrence of a transient ischaemic attack (defined as not related to the treatment) and 2 for administrative reasons. A significantly (p < 0.01) different effect in favour of oxiracetam was observed on the quality of life scale, and confirmed by significant (defined according to the Bonferroni technique) differences in some neuropsychological tests (e.g. controlled associations, short story). Four patients in the oxiracetam group complained of a total of 5 unwanted effects, and 1 on placebo complained of 3 unwanted effects, but none of them was withdrawn from the study.     

Characteristics of dyslexia and dysgraphia in a Chinese patient with semantic dementia

We describe a 44-year-old Chinese-speaking patient with semantic dementia (SD), who demonstrates dyslexia and dysgraphia. The man was administered a series of neuropsychological inspections, including general language tests and reading and writing examinations. The patient demonstrated surface dyslexia when reading single Chinese characters aloud. While most writing errors demonstrated by the patient were orthographically similar errors and noncharacter responses, such as pictograph, logographeme, and stroke errors, rather than phonologically plausible errors that were homophonous or different only in tone from the targets. We suggest that the type of acquired dysgraphia demonstrated by Chinese-speaking SD patients is determined by the unique features of the Chinese writing system.     

A MEG study of the neural substrates of semantic processing in semantic variant primary progressive aphasia

Despite a well-documented pattern of semantic impairment, the patterns of brain activation during semantic processing in semantic variant primary progressive aphasia (svPPA) still remain poorly understood. In the current study, one svPPA patient (EC) and six elderly controls carried out a general-level semantic categorization task while their brain activity was recorded using magnetoencephalography (MEG). Despite similar behavioral performance, EC showed hyperactivation of the left inferior temporal gyrus (ITG) and right anterior temporal lobe (ATL) relative to controls. This suggests that periatrophic regions within the ATL region may support preserved semantic abilities in svPPA.     

Multi-infarct dementia: a computed tomographic study

CT Scan of 30 patients with multi-infarct dementia (MID) were compared with age- and sex-matched controls. Infarcts were seen in 93% of MID cases and 10% of controls. A marked difference in the occurrence of white matter low attenuation was seen between the groups. All the parameters of cerebral atrophy studied showed a statistically significant correlation with the presence of dementia.