[Simultanagnosia caused by cerebral infarction in the right temporal stem, right lateral thalamus, and right pulvinar regions].

A 76-year-old male patient was admitted to our hospital for the treatment of acute cerebral infarction in the right temporal stem, right lateral thalamus, and right pulvinar regions. Although his overall cognitive function was almost normal, he exhibited reduced visual sensitivity in the homonymous lower left quadrant of the visual field, left unilateral spatial neglect (USN), and simultanagnosia. Left USN improved 4 months after the onset of infarction; however, simultanagnosia persisted. To the best of our knowledge, this is the first case of simultanagnosia caused by cerebral infarction in the right temporal stem, right lateral thalamus, and right pulvinar regions.

[Non-aphasic misnaming: a case report and literature review].

A 71-year-old, right-handed woman was admitted to our hospital due to a sudden difficulty with conversation. On admission, she was alert, but had a euphoric mood, disorientation, and a disturbance of recent memory. Her speech was fluent. Her repetition and auditory word cognition were excellent, but she had a slight difficulty with naming visual objects. She frequently showed word-finding difficulty and irrelevant paraphasia during free conversation and a word fluency task. Her irrelevant paraphasia was observed more frequently when she was asked to explain her outbreak of anger at the hospital, i.e., it was situation-dependent. She also had anosognosia. MRI showed an infarct in the territory of the left tuberothalamic artery. Single-photon emission computed tomography revealed low-uptake lesions in the left thalamus and orbital frontal, medial frontal, and medial temporal lobes. The patient was diagnosed with non-aphasic misnaming. The clinical characteristics of patients with non-aphasic misnaming in the literature were reviewed. All of the patients with non-aphasic misnaming had word-finding difficulty and irrelevant paraphasia. Additionally, they had either emotional disturbance or anosognosia.

The right thalamic ventral posterolateral nucleus seems to be determinant for macrosomatognosia: a case report.

BACKGROUND: Macrosomatognosiais the illusory sensation of a substantially enlarged body part. This disorder of the body schema, also called "Alice in wonderland syndrome" is still poorly understood and requires careful documentation and analysis of cases. The patient presented here is unique owing to his unusual macrosomatognosia phenomenology, but also given the unreported localization of his most significant lesion in the right thalamus that allowed consistent anatomo-clinical analysis. CASE PRESENTATION: This 45-years old man presented mainly with long-lasting and quasi-delusional macrosomatognosia associated to sensory deficits, both involving the left upper-body, in the context of a right thalamic ischemic lesion most presumably located in the ventral posterolateral nucleus. Fine-grained probabilistic and deterministic tractography revealed the most eloquent targets of the lesion projections to be the ipsilateral precuneus, superior parietal lobule,but also the right primary somatosensory cortex and, to a lesser extent, the right primary motor cortex. Under stationary neurorehabilitation, the patient slowly improved his symptoms and could be discharged back home and, later on, partially return to work. CONCLUSION: We discuss deficient neural processing and integration of sensory inputs within the right ventral posterolateral nucleus lesion as possible mechanisms underlying macrosomatognosia in light of observed anatomo-clinical correlations. On the other hand, difficulty to classify this unique constellation of Alice in wonderland syndrome calls for an alternative taxonomy of cognitive and psychic aspects of illusory body-size perceptions.

Anosognosia en la enfermedad de Alzheimer: prevalencia, factores asociados e influencia en la evolución de la enfermedad / Anosognosia in Alzheimer disease: Prevalence, associated factors, and influence on disease progression

Introducción: La anosognosia es frecuente en la enfermedad de Alzheimer (EA). El objetivo fue describir su prevalencia en el momento del diagnóstico y analizar los factores predisponentes y su influencia en la evolución posterior de la EA. Métodos: Estudio observacional, multicéntrico, prospectivo, analítico, realizado en consultas de neurología general. Se incluyó a pacientes recién diagnosticados de EA (criterios NINCDS-ADRDA). Se realizaron 2 evaluaciones -cognitivas, funcionales y neuropsiquiátricas-, con un intervalo de 18 meses. Se empleó la Clinical Insight Rating scale como medida de anosognosia (CIR, rango 0-8). El criterio de progresión fue un incremento en la Clinical Dementia Rating-sum of boxes mayor a 2,5 puntos. Las variables predictoras se analizaron mediante regresión logística. Resultados: Se incluyó a 127 pacientes, 94 completaron las 2 evaluaciones. El 31,5% mostraba anosognosia grave (CIR 7-8), el 39,4% conciencia alterada (CIR 3-6) y el 29,1% conciencia normal (CIR 0-2). La mediana del CIR basal en la cohorte fue 4 (Q1-Q3: 1-7) y a los 18 meses 6 (Q1-Q3: 3-8); p < 0,001. La edad avanzada (odds ratio [OR] 2,43; IC del 95%, 1,14-5,19), menor escolaridad (OR 2,15; IC del 95%, 1,01-4,58) y mayor afectación neuropsiquiátrica (OR 2,66; IC del 95%, 1,23-5,74) fueron variables predictoras de anosognosia. El CIR basal fue similar en los grupos con y sin progresión clínica significativa. Conclusiones: La gran mayoría de los pacientes con EA en el momento del diagnóstico muestran un grado significativo de anosognosia que se asocia a mayor edad, menor escolaridad y mayor afectación conductual. No se demostró influencia de la anosognosia sobre la evolución inicial de la EA tras el diagnóstico

Introduction: Anosognosia is a frequent symptom in Alzheimer disease (AD). The objective of this article is to describe prevalence of this condition at time of diagnosis and analyse any predisposing factors and their influence on disease progression. Methods: Observational, prospective, and analytical multi-centre study in an outpatient setting. Patients recently diagnosed with AD (NINCDS-ADRDA criteria) were included. Each patient underwent two cognitive, functional, and neuropsychiatric assessments separated by an interval of 18 months. The Clinical Insight Rating Scale was employed as a measure of anosognosia (CIR, scored 0-8). Progression was defined as an increase in the Clinical Dementia Rating Scale-sum of boxes of more than 2.5 points. The predictor variables were analysed using binary logistic regression. Results: The study included 127 patients, and 94 completed both assessments. Of the total, 31.5% displayed severe anosognosia (CIR 7-8); 39.4%, altered level of consciousness (CIR 3-6); and 29.1%, normal awareness (CIR 0-2). The median baseline CIR in this cohort was 4 (Q1-Q3: 1-7), and at 18 months, 6 (Q1-Q3: 3-8), P<.001. Advanced age (odds ratio (OR) 2.43; CI 95%:1.14-5.19), lower educational level (OR 2.15; CI 95%:1.01-4.58), and more marked neuropsychiatric symptoms (OR 2.66; CI 95%:1.23-5.74) were predictor variables of anosognosia. Baseline CIR was similar in the groups with and without significant clinical progression. Conclusions: The large majority of patients with AD at the time of diagnosis showed significant anosognosia, and this condition was associated with advanced age, lower educational level, and more marked behavioural symptoms. Our results did not show that anosognosia had an effect on the initial clinical progression of AD after diagnosis

Auditory agnosia as a clinical symptom of childhood adrenoleukodystrophy.

OBJECTIVE: To investigate detailed auditory features in patients with auditory impairment as the first clinical symptoms of childhood adrenoleukodystrophy (CSALD). SUBJECTS AND METHODS: Three patients who had hearing difficulty as the first clinical signs and/or symptoms of ALD. Precise examination of the clinical characteristics of hearing and auditory function was performed, including assessments of pure tone audiometry, verbal sound discrimination, otoacoustic emission (OAE), and auditory brainstem response (ABR), as well as an environmental sound discrimination test, a sound lateralization test, and a dichotic listening test (DLT). The auditory pathway was evaluated by MRI in each patient. RESULTS: Poor response to calling was detected in all patients. Two patients were not aware of their hearing difficulty, and had been diagnosed with normal hearing by otolaryngologists at first. Pure-tone audiometry disclosed normal hearing in all patients. All patients showed a normal wave V ABR threshold. Three patients showed obvious difficulty in discriminating verbal sounds, environmental sounds, and sound lateralization and strong left-ear suppression in a dichotic listening test. However, once they discriminated verbal sounds, they correctly understood the meaning. Two patients showed elongation of the I-V and III-V interwave intervals in ABR, but one showed no abnormality. MRIs of these three patients revealed signal changes in auditory radiation including in other subcortical areas. CONCLUSION: The hearing features of these subjects were diagnosed as auditory agnosia and not aphasia. It should be emphasized that when patients are suspected to have hearing impairment but have no abnormalities in pure tone audiometry and/or ABR, this should not be diagnosed immediately as psychogenic response or pathomimesis, but auditory agnosia must also be considered.

Agnosic or semantic impairment in very mild Alzheimer's disease?

The present study investigated object recognition impairment and the existence of category effects in patients with mild Alzheimer's disease. A battery of tests was designed to assess the deterioration of semantic memory and/or the existence of agnosia by evaluating visual and auditory naming, knowledge of structural descriptions (pre-semantic representation of an object within each perceptual system) and conceptual knowledge. The group of Alzheimer's patients were impaired in all experimental tests as compared to healthy participants. This result suggests an impairment of multiple levels of object integration processing even at an early stage of the disease. The patients also demonstrated a category effect with massive difficulties in recognizing human actions and musical instruments as compared to the other categories. This study provides an innovative clinical tool for exploring the recognition of visual and auditory objects at different levels of representation, allowing for the description of early signs of Alzheimer disease.

Compensational strategies for a merchant after stroke with anosognosia for alexia without agraphia.

We report the first case, to our knowledge, of successful return to work of a patient with alexia without agraphia. This case is also interesting as it is the first report of which we are aware of anosognosia for alexia without agraphia: the patient confabulated when asked to read English text, but immediately stated that he could not read Chinese text because he did not know that language. The selective nature of this confabulation would not be inconsistent with anosognosia being one of the brain's responses to absence of afferent information.

Cortical activation during clock reading as a quadratic function of dementia state.

In patients with Alzheimer's disease (AD), neuroimaging studies have demonstrated decreased brain activation, while increased activation was detected in patients with mild cognitive impairment (MCI). It can be hypothesized that increased cerebral activity seen in patients with MCI reflects neural compensation at the beginning of neurodegenerative processes. Later, as patients develop AD, neural integrity is increasingly impaired. This is accompanied by decreased neural activation. In this study we examined cognitive performance and functional magnetic resonance imaging activation on a Clock Reading task (CRT) and a Spatial Control task (SCT) in healthy controls, patients with MCI, and patients with early AD. Correlations between neural-functional activation and cognitive state, measured by the Mini Mental Status Examination, were determined using rank, linear and quadratic correlation models. It could be shown that CRT, in comparison to SCT, specifically activates brain regions in the ventral visual stream and precuneus known to be involved in conceptual processing and spatial imagery. The correlation between brain activity and cognitive state followed a quadratic rather than a linear pattern in several brain regions, including the lingual gyrus, cuneus, and precuneus. The strongest brain activity was found in patients with MCI and less severely impaired early AD subjects. These findings support the hypothesis that patients in early stages of dementia compensate for neuronal loss by the recruitment of additional neural resources reflected by increased neural activation, as measured by the blood oxygen level-dependent signal.

The frequency, clinical correlates, and mechanism of anosognosia after stroke.

OBJECTIVE: To review the frequency, clinical correlates, and mechanism of anosognosia after stroke. METHODS: We searched the most recent relevant literature on anosognosia after stroke and carried out a critical analysis of the main findings. RESULTS: Anosognosia is present in about 10% of acute stroke patients and its diagnosis is relatively simple. Nevertheless, a valid and reliable standardization of diagnostic instruments and criteria for research purposes is more difficult to achieve. This limitation may partially account for various instruments available to assess anosognosia and the different strategies used to diagnose this phenomenon. Anosognosia is a fleeting phenomenon and chronic cases are infrequent. There is a robust association between anosognosia and right-hemisphere lesions involving cortical (insular, temporal, and parietal lobes) and subcortical structures (thalamus and basal ganglia). The main clinical correlates of anosognosia are the presence of neglect, cognitive deficits, previous strokes, and older age. Anosognosia has a negative impact on the rehabilitation of stroke patients. The mechanism of anosognosia remains unknown but was explained as owing to psychological denial, disconnection between left and right hemispheres, and dysfunction of a system that monitors the intention to move and actual movements. CONCLUSION: Anosognosia is a relatively frequent complication of acute stroke and may become an excellent model to understand the mechanism of human awareness.

The evaluation of anosognosia in stroke patients.

BACKGROUND: Anosognosia in stroke patients showed a relevant detrimental effect on the rehabilitation course and patients' quality of life, especially in those with brain injury. Although a number of reliable scales for the assessment of anosognosia in stroke and traumatic brain injury have been developed, at present no single measure fully explores the multifaceted nature of the phenomenon. METHOD: A PubMed search with appropriate terms was carried out in order to critically review the issue. RESULTS: The main dimensions to consider in the investigation of anosognosia in brain-injured patients are (a) awareness of deficit and related functional implications, (b) modality specificity, (c) causal attribution, (d) expectations of recovery, (e) implicit knowledge and (f) differential diagnosis with psychological denial. Time elapsed from stroke, aetiology, laterality, aphasia and clinical complications may influence all these characteristics and must be taken into consideration. Finally, an adequate association of the anosognosia evaluation with other neuropsychological and behavioural aspects is relevant for a modern holistic approach to the patient. CONCLUSIONS: This review is meant to stimulate the development of a new comprehensive assessment procedure for anosognosia in brain injury and particularly in stroke, in order to catch the multidimensionality of the phenomenon and to shape rehabilitation programmes suitable to the specific clinical features of every single patient.

Simultanagnosia: when a rose is not red.

Abstract Information regarding object identity ("what") and spatial location ("where/how to") is largely segregated in visual processing. Under most circumstances, however, object identity and location are linked. We report data from a simultanagnosic patient (K.E.) with bilateral posterior parietal infarcts who was unable to "see" more than one object in an array despite relatively preserved object processing and normal preattentive processing. K.E. also demonstrated a finding that has not, to our knowledge, been reported: He was unable to report more than one attribute of a single object. For example, he was unable to name the color of the ink in which words were written despite naming the word correctly. Several experiments demonstrated, however, that perceptual attributes that he was unable to report influenced his performance. We suggest that binding of object identity and location is a limited-capacity operation that is essential for conscious awareness for which the posterior parietal lobe is crucial.

Early-stage visual processing and cortical amplification deficits in schizophrenia.

BACKGROUND: Patients with schizophrenia show deficits in early-stage visual processing, potentially reflecting dysfunction of the magnocellular visual pathway. The magnocellular system operates normally in a nonlinear amplification mode mediated by glutamatergic (N-methyl-D-aspartate) receptors. Investigating magnocellular dysfunction in schizophrenia therefore permits evaluation of underlying etiologic hypotheses. OBJECTIVES: To evaluate magnocellular dysfunction in schizophrenia, relative to known neurochemical and neuroanatomical substrates, and to examine relationships between electrophysiological and behavioral measures of visual pathway dysfunction and relationships with higher cognitive deficits. DESIGN, SETTING, AND PARTICIPANTS: Between-group study at an inpatient state psychiatric hospital and outpatient county psychiatric facilities. Thirty-three patients met DSM-IV criteria for schizophrenia or schizoaffective disorder, and 21 nonpsychiatric volunteers of similar ages composed the control group. MAIN OUTCOME MEASURES: (1) Magnocellular and parvocellular evoked potentials, analyzed using nonlinear (Michaelis-Menten) and linear contrast gain approaches; (2) behavioral contrast sensitivity measures; (3) white matter integrity; (4) visual and nonvisual neuropsychological measures, and (5) clinical symptom and community functioning measures. RESULTS: Patients generated evoked potentials that were significantly reduced in response to magnocellular-biased, but not parvocellular-biased, stimuli (P = .001). Michaelis-Menten analyses demonstrated reduced contrast gain of the magnocellular system (P = .001). Patients showed decreased contrast sensitivity to magnocellular-biased stimuli (P<.001). Evoked potential deficits were significantly related to decreased white matter integrity in the optic radiations (P<.03). Evoked potential deficits predicted impaired contrast sensitivity (P = .002), which was in turn related to deficits in complex visual processing (P< or =.04). Both evoked potential (P< or =.04) and contrast sensitivity (P = .01) measures significantly predicted community functioning. CONCLUSIONS: These findings confirm the existence of early-stage visual processing dysfunction in schizophrenia and provide the first evidence that such deficits are due to decreased nonlinear signal amplification, consistent with glutamatergic theories. Neuroimaging studies support the hypothesis of dysfunction within low-level visual pathways involving thalamocortical radiations. Deficits in early-stage visual processing significantly predict higher cognitive deficits.

Writing, calculating, and finger recognition in the region of the angular gyrus: a cortical stimulation study of Gerstmann syndrome.

OBJECT: In an attempt to gain a better understanding of the cerebral functions represented in the angular gyrus and to spare them during surgery, the authors studied patients with brain tumors located close to the angular gyrus and mapped cortical sites by using electrostimulation. METHODS: Before undergoing tumor removal, six right-handed patients (five with left and one with right hemisphere tumors) were studied using cortical mapping with the aid of calculating, writing, finger-recognition, and color-naming tasks in addition to standard reading and object-naming tasks (for a total of 36 brain mapping studies). Strict conditions of functional site validation were applied to include only those cortical sites that produced repetitive interferences in the function tested. Preoperatively, four of the patients exhibited discrete symptoms related to Gerstmann syndrome while performing very specific tasks, whereas the other two patients presented with no symptoms of the syndrome. No patient had significant language or apraxic deficits. Distinct or shared cortical sites producing interferences in calculating, finger recognition, and writing were repeatedly found in the angular gyrus. Object- or color-naming sites and reading-interference sites were also found in or close to the angular gyrus; although frequently demonstrated, these latter results were variable and unpredictable in the group of patients studied. Finger agnosia and acalculia sites were also found elsewhere, such as in the supramarginal gyrus or close to the intraparietal sulcus. Mechanisms involved in acalculia, agraphia, or finger agnosia (either complete interferences or hesitations) during stimulation were various, from an aphasia-like form (for instance, the patient did not understand the numbers or words given for calculating or writing tasks) to an apparently pure interference in the function tested (patients understood the numbers, but were unable to perform a simple addition). CONCLUSIONS: Symptoms of Gerstmann syndrome can be found during direct brain mapping in the angular gyrus region. In this series of patients, sites producing interferences in writing, calculating, and finger recognition were demonstrated in the angular gyrus, which may or may not have been associated with object-naming, color-naming, or reading sites.

Posterior alien hand syndrome after a right thalamic infarct.

The alien hand syndrome, as originally defined, should be reserved for cases in which the hand feels foreign "together with" observable involuntary motor activity. These involuntary movements are unusual during or after acute stroke. Three varieties of alien hand syndrome have been reported, involving lesions of the corpus callosum alone, the corpus callosum plus dominant medial frontal cortex, and posterior cortical and subcortical areas. A patient with posterior alien hand syndrome of vascular aetiology is reported. Imaging studies disclosed an isolated infarction of the right thalamus sparing other cerebral regions.

Perceiving left and imagining right: dissociation in neglect.

Signor Piazza, a patient with a left parieto-occipital haemorrhage and a right thalamic stroke, showed severe right personal neglect (e.g. touching own body parts) and right perceptual neglect in tasks with (e.g. cancelling tasks) or without (e.g. description of a complex picture) motor response. He had also right-sided neglect dyslexia (including single words), without language impairments. However, the patient also presented with a clear left-sided deficit in the representational domain (e.g. imagery tasks). Signor Piazza's pattern of performance suggests dissociation between imagery and perception within the neglect syndrome.

Receptive amusia: evidence for cross-hemispheric neural networks underlying music processing strategies.

Perceptual musical functions were investigated in patients suffering from unilateral cerebrovascular cortical lesions. Using MIDI (Musical Instrument Digital Interface) technique, a standardized short test battery was established that covers local (analytical) as well as global perceptual mechanisms. These represent the principal cognitive strategies in melodic and temporal musical information processing (local, interval and rhythm; global, contour and metre). Of the participating brain-damaged patients, a total of 69% presented with post-lesional impairments in music perception. Left-hemisphere-damaged patients showed significant deficits in the discrimination of local as well as global structures in both melodic and temporal information processing. Right-hemisphere-damaged patients also revealed an overall impairment of music perception, reaching significance in the temporal conditions. Detailed analysis outlined a hierarchical organization, with an initial right-hemisphere recognition of contour and metre followed by identification of interval and rhythm via left-hemisphere subsystems. Patterns of dissociated and associated melodic and temporal deficits indicate autonomous, yet partially integrated neural subsystems underlying the processing of melodic and temporal stimuli. In conclusion, these data contradict a strong hemispheric specificity for music perception, but indicate cross-hemisphere, fragmented neural substrates underlying local and global musical information processing in the melodic and temporal dimensions. Due to the diverse profiles of neuropsychological deficits revealed in earlier investigations as well as in this study, individual aspects of musicality and musical behaviour very likely contribute to the definite formation of these widely distributed neural networks.

Memories are made of this: the effects of time on stored visual knowledge in a case of visual agnosia.

We report the effects of the passage of time on the longterm visual knowledge for objects in a patient with visual agnosia (H.J.A.). The naming of real objects was found to have improved, although this was not associated with any change in H.J.A.'s basic perceptual abilities which were stable over a 16-year period. The improvement in object naming was attributed to better use of non-contour-based visual information (such as surface detail and depth cues). In addition, we demonstrate a deterioration in H.J.A.'s long-term memory for the visual properties of objects, and argue that this has occurred as a result of his having impaired perceptual input. The deterioration was only apparent in drawing from memory and in the verbal descriptions of items; with forced-choice testing, H.J.A. operated at ceiling; we propose that current tests of visual imagery may not be sufficiently sensitive to detect subtle impairments of visual memory. Our findings can be taken to indicate that perceptual and memorial processes are not functionally independent, but are linked in an interactive manner.

One or several semantic system(s)? Maybe none: evidence from a case study of modality and category-specific "semantic" impairment.

Following cerebral anoxia, EC a 55-year-old patient, exhibited a severe and clear-cut pattern of semantic impairments without general intellectual deficit or perceptual difficulty. EC demonstrated a complex neuropsychological picture including a massive visual agnosia and a complete lack of imagery, both of which involved all categories of objects (living and non living) and a category-specific word comprehension deficit limited to animal names. Findings are discussed in the light of the theoretical frameworks currently available in the area of neuropsychology. It is argued that neither the single nor the multiple view of semantics fully succeed in providing a satisfactory account of the data and a tentative interpretation of the whole pattern of impairment is proposed in the general framework of non abstractive conceptions of meaning.

Object recognition difficulty in visual apperceptive agnosia.

Two patients with visual apperceptive agnosia were examined on tasks assessing the appreciation of visual material. Elementary visual functioning was relatively preserved, but they had profound difficulty recognizing and naming line drawings. More detailed evaluation revealed accurate recognition of regular geometric shapes and colors, but performance deteriorated when the shapes were made more complex visually, when multiple-choice arrays contained larger numbers of simple targets and foils, and when a mental manipulation such as a rotation was required. The recognition of letters and words was similarly compromised. Naming, recognition, and anomaly judgments of colored pictures and real objects were more accurate than similar decisions involving black-and-white line drawings. Visual imagery for shapes, letters, and objects appeared to be more accurate than visual perception of the same materials. We hypothesize that object recognition difficulty in visual apperceptive agnosia is due to two related factors: the impaired appreciation of the visual perceptual features that constitute objects, and a limitation in the cognitive resources that are available for processing demanding material within the visual modality.