John Marshall and the cognitive neuropsychology of reading

Contemporary cognitive neuropsychology owes a great debt to John Marshall. His pioneering work on acquired and developmental disorders of reading established the principles by which cognitive-neuropsychological theorizing operates as well as leading to a profound understanding of the nature of reading disorders which has subsequently influenced their assessment and treatment.     

The neuropsychology of preclinical Alzheimer's disease and mild cognitive impairment

Subjects in the preclinical stages of Alzheimer's disease (AD) typically record neuropsychological performance between that of healthy older individuals and demented patients. More specifically, deficits on measures of verbal episodic memory are commonly reported in these patients, while other cognitive functions (e.g. language, praxis and executive function) seem to be spared. A similar neuropsychological profile is observed in elderly subjects with mild cognitive impairment (MCI), a disorder that is attracting increasing research interest. Evidence from lesion and functional imaging studies, as well as volumetric imaging in probable AD and MCI patients, suggests that the cognitive deficits observed in these disorders may be related to medial temporal lobe dysfunction. An issue currently under investigation is whether MCI represents the preclinical stages of AD or a distinct and static cognitive aetiology. In an attempt to address this issue, present investigations are adopting a convergent approach to the detection of preclinical AD, where multiple risk factors are considered when making a diagnosis.     

The cognitive neuropsychology of auditory hallucinations: a parallel auditory pathways framework

Auditory hallucinations are generally defined as false perceptions. Recent developments in auditory neuroscience have rapidly increased our understanding of normal auditory perception revealing (partially) separate pathways for the identification ("what") and localization ("where") of auditory objects. The current review offers a reexamination of the nature of auditory hallucinations in schizophrenia using this object-based framework. First, the structural and functional organization of auditory what and where pathways is briefly described. Then, using recent functional neuroimaging data from healthy subjects and patients with schizophrenia, key phenomenological features of hallucinations are linked to abnormal processing both within and between these pathways. Finally, current cognitive explanations of hallucinations, based on intrusive cognitions and impaired source memory, are briefly outlined and set within this framework to provide an integrated cognitive neuropsychological model of auditory hallucinations.     

The cerebellum may be directly involved in cognitive functions

Neuropsychological deficits may occur in infratentorial strokes. Only minor cognitive disturbances are reported in unilateral anterior cerebellar lesions. Here, the authors describe a patient with bilateral anterior ponto-cerebellar ischemic lesions associated with major neuropsychological deficits. Cerebral PET and SPECT demonstrated no metabolic defect in supratentorial areas.     

The cerebellum: from motor coordination to cognitive function

Clinical data in man, as well as experimental results in animals, classically involve the cerebellum in the coordination of ballistic movements and in their accompanying postural adjustment. The cerebellum intervenes in the coding of the order and duration of contraction of the different protagonist muscular groups contributing to the same movement. In normal life, this is an automatic, non conscious procedure. Recent studies seem to indicate that the human neocerebellum (lateral hemispheres and dentate nuclei) plays a role in the regulation of some neocortical cognitive functions. This new functional aspect of cerebellar activity has been inferred from the results obtained by three quite different domains: neuroanatomical data showing the existence of, sometimes reciprocal, pathways between the neocerebellum and associative and limbic areas in primates, neuropsychological data assessing the presence, in some cerebellar patients, of purely cognitive impairments, and data from functional imagery pointing out cerebellar activation in healthy subjects during non motor tasks. II would ensue that, thanks to new cortical targets. The cerebellum could regulate sensorial, procedural, linguistic and emotional activities, so that a cerebellar lesion could be followed by a cognitive and affective syndrome, depending on the importance and on the location of the lesion.     

Theoretical and methodological issues in the cognitive neuropsychology of spoken word production

This paper reviews the ''state of the art'' in the cognitive neuropsychology of spoken word production. It first examines current theoretical issues, specifically addressing the questions: How many levels of processing are there in word production? How does activation flow between levels of processing? What is the relationship between spoken word production and other aspects of language processing? What is the relationship between phonology for lexical and non-lexical forms? The discussion then turns to methodological issues in cognitive neuropsychology, contrasting group, case series, and single case study approaches. Finally, a detailed examination is made of different types of case series approach.     

The cerebellum in cognitive processes: Supporting studies in children

Over the last decade, increasing evidence of cognitive functions of the cerebellum during development and learning processes could be ascertained. Posterior fossa malformations such as cerebellar hypoplasia or Joubert syndrome are known to be related to developmental problems in a marked to moderate extent. More detailed analyses reveal special deficits in attention, processing speed, visuospatial functions and language. A study about Dandy Walker syndrome states a relationship of abnormalities in vermis lobulation with developmental problems. Further lobulation or volume abnormalities of the cerebellum and/or vermis can be detected in disorders as fragile X syndrome, Downs’s syndrome or William’s syndrome. Neuropsychological studies reveal a relation of dyslexia and attention deficit disorder with cerebellar functions. These functional studies are supported by structural abnormalities in neuroimaging in these disorders. Acquired cerebellar or vermis atrophy was found in groups of children with developmental problems such as prenatal alcohol exposure or extreme prematurity. Also focal lesions during childhood or adolescence such as cerebellar tumour or stroke are related with neuropsychological abnormalities, which are most pronounced in visuo-spatial, language and memory functions. In addition, cerebellar atrophy was shown to be a bad prognostic factor considering cognitive outcome in children after brain trauma and leukaemia. In ataxia teleangiectasia, a neurodegenerative disorder affecting primarily the cerebellar cortex, a reduced verbal IQ and problems of judgment of duration are a hint of the importance of the cerebellum in cognition. In conclusion, the cerebellum seems to play an important role in many higher cognitive functions especially in learning. There is a suggestion that the earlier the incorrect influence the more pronounced the problems.     

The developmental relationship between specific cognitive domains and grey matter in the cerebellum

There is growing evidence that the cerebellum is involved in cognition and cognitive development, yet little is known about the developmental relationship between cerebellar structure and cognitive subdomains in children. We used voxel-based morphometry to assess the relationship between cerebellar grey matter (GM) and language, reading, working memory, executive function, and processing speed in 110 individuals aged 8–17 years from the Pediatric Imaging, Neurocognition, and Genetics (PING) Study. Further, we examined the effect of age on the relationships between cerebellar GM and cognition. Higher scores on vocabulary, reading, working memory, and set-shifting were associated with increased GM in the posterior cerebellum (lobules VI–IX), in regions which are typically engaged during cognitive tasks in healthy adults. For reading, working memory, and processing speed, the relationship between cerebellar GM and cognitive performance changed with age in specific cerebellar subregions. As in adults, posterior lobe cerebellar GM was associated with cognitive performance in a pediatric population, and this relationship mirrored the known developmental trajectory of posterior cerebellar GM. These findings provide further evidence that specific regions of the cerebellum support cognition and cognitive development, and suggest that the strength of this relationship depends on developmental stage.     

Myths of neuropsychology: intelligence, neurometabolism, and cognitive ability

Recently, Dodrill (1999) revised a previously described "Myth of neuropsychology" (1997) to state: "Just as below average performances on neuropsychological tests are found when intelligence is below average, to that same degree above average performances on neuropsychological tests are expected when intellectual abilities are above average." This study addresses the relationship between intellectual and neuropsychological performance in the context of Magnetic Resonance Spectroscopy (MRS) measurements of the neurometabolite N-acetylaspartate (NAA). When subjects were stratified by Full Scale IQ (Average, High Average, Superior) they differed significantly in terms of total neuropsychological performance [F(2,47) = 17.63; p <.001] and the neuronal marker NAA [F(2,47) = 3.25; p <.05]. Regression analysis across groups demonstrated that FSIQ and NAA were independently related to Total z-score [F(1,47) = 29.43; p <.0001] and accounted for over half the variance (r(2) of model =.56). The concurrent relationship of FSIQ and NAA to total neuropsychological performance suggests that the relationship between measures sensitive to intellectual ability and neuropsychological performance is real, and does not reflect arbitrary psychometric or scaling properties of the WAIS-III.     

Toward a cognitive neuropsychology of awareness: implicit knowledge and anosognosia

Although a systematic cognitive neuropsychology of awareness has not yet emerged, a number of phenomena reported in the literature provide an empirical basis for developing it. The present discussion focusses on two such phenomena: implicit knowledge, which refers to knowledge that is expressed in task performance unintentionally and with little phenomenal awareness; and anosognosia, which refers to unawareness of neuropsychological deficits. Two types of theoretical accounts of these phenomena are discussed. A first order theoretical account entails postulating damage to, or disconnection of, a system or process that generates awareness across multiple domains. A second-order account does not postulate disruption of a cross-domain awareness mechanism, but instead appeals to difficulties in gaining access to particular kinds of domain-specific information that are associated with aware expressions of knowledge in individual domains. Instances of first- and second-order accounts are illustrated with examples from studies of memory and amnesia. The relation between implicit knowledge and anosognosia is also discussed.     

小血管病性血管性认知障碍非痴呆型患者神经心理学特征的研究

目的通过系列神经心理学测试对小血管病性血管性认知障碍非痴呆型(VCIND-SVD)患者的神经心理学特征进行分析,寻找适用于VCIND-SVD患者的敏感且简捷的神经心理评估工具。方法VCIND-SVD患者33例,正常对照组40例,进行MMSE及多个包括5个认知域在内的神经心理学测试,确定VCIND-SVD患者受损的认知域,筛选出识别能力较好的单项测试,检测其敏感度和特异度,以便临床使用。结果VCIND-SVD患者为多个认知域损害,包括记忆力、注意力、语言功能、视空间结构技能及执行功能均有损害;即刻逻辑记忆测试、积木测试、伦敦塔完成时间及计划时间等检测项目能敏感反映这些损害。结论各单项测试的综合对VCIND-SVD具有较强的识别能力,有重要的应用价值。