Deafness for the meanings of number words

We describe the performance of an aphasic individual who showed a selective impairment affecting his comprehension of auditorily presented number words and not other word categories. His difficulty in number word comprehension was restricted to the auditory modality, given that with visual stimuli (written words, Arabic numerals and pictures) his comprehension of number and non-number words was intact. While there have been previous reports of selective difficulty or sparing of number words at the semantic and post-semantic levels, this is the first reported case of a pre-semantic deficit that is specific to the category of number words. This constitutes evidence that lexical semantic distinctions are respected by modality-specific neural mechanisms responsible for providing access to the meanings of words

The black box of global aphasia: Neuroanatomical underpinnings of remission from acute global aphasia with preserved inner language function

Objective We studied an unusual case of global aphasia (GA) occurring after brain tumor removal and remitting one-month after surgery. After recovering, the patient reported on her experience during the episode, which suggested a partial preservation of language abilities (such as semantic processing) and the presence of inner speech (IS) despite a failure in overt speech production. Thus, we explored the role of IS and preserved language functions in the acute phase and investigated the neuroanatomical underpinnings of this severe breakdown in language processing. Method A neuropsychological and language assessment tapping into language production, comprehension, attention and working memory was carried out both before and three months after surgery. In the acute stage a simplified protocol was tailored to assess the limited language abilities and further explore patient's performance on different semantic tasks. The neuroanatomical dimension of these abrupt changes was provided by perioperative structural neuroimaging. Results Language and neuropsychological performance were normal/close to normal both before and three months after surgery. In the acute stage, the patient presented severe difficulties with comprehension, production and repetition, whereas she was able to correctly perform tasks that requested conceptual analysis and non-verbal operations. After recovering, the patient reported that she had been able to internally formulate her thoughts despite her overt phonological errors during the episode. Structural neuroimaging revealed that an extra-axial blood collection affected the middle frontal areas during the acute stage and that the white matter circuitry was left-lateralized before surgery. Conclusions We deemed that the global aphasia episode was produced by a combination of the post-operative extra-axial blood collection directly impacting left middle frontal areas and a left-lateralization of the arcuate and/or uncinated fasciculi before surgery. Additionally, we advocate for a comprehensive evaluation of linguistic function that includes the assessment of IS and non-expressive language functions in similar cases

Language recovery and evidence of residual deficits after nonthalamic subcortical stroke: A 1 year follow-up study

A variety of language disturbances including aphasia have been described after subcortical stroke but less is known about the factors that influence the long-term recovery of stroke-induced language dysfunction. We prospectively examined the role of the affected hemisphere and the lesion site in the occurrence and recovery of language deficits in nonthalamic subcortical stroke. Forty patients with unilateral basal gangliastroke underwent language assessment within 1 week, 3 months and 1 year after stroke. Disturbances in at least one language domain were observed in 35 patients during the first week post stroke including aphasia diagnosed in 11 patients. Importantly, the appearance of deficits after stroke onset and the improvement of language function were not determined by the site of subcortical lesion, but instead were critically influenced by the affected hemisphere. In fact, the language impairments following left and right basal ganglia stroke mirrored the language dysfunction observed after cortical lesions in the same hemisphere. A significant overall language improvement was observed at 3 months after stroke, although residual deficits in languageexecutive function were the most commonly observed impairment at 1 year follow-up. Although a substantial improvement of language function can be expected after nonthalamic subcortical stroke, our findings suggest that language recovery may not be fully achieved at 1 year pos

Auditory target and novelty processing in patients with unilateral hippocampal sclerosis: A current-source density study

The capacity to respond to novel events is crucial for adapting to the constantly changing environment. Here, we recorded 29-channel Event Related Brain Potentials (ERPs) during an active auditory novelty oddball paradigm and used for the first time Current Source Density-transformed Event Related Brain Potentials and associated time-frequency spectra to study target and novelty processing in a group of epileptic patients with unilateral damage of the hippocampus (N = 18) and in healthy matched control participants (N = 18). Importantly, we used Voxel-Based Morphometry to ensure that our group of patients had a focal unilateral damage restricted to the hippocampus and especially its medial part. We found a clear deficit for target processing at the behavioral level. In addition, compared to controls, our group of patients presented (i) a reduction of theta event-related synchronization (ERS) for targets and (ii) a reduction and delayed P3a source accompanied by reduced theta and low-beta ERS and alpha event-related synchronization (ERD) for novel stimuli. These results suggest that the integrity of the hippocampus might be crucial for the functioning of the complex cortico-subcortical network involved in the detection of novel and target stimuli

Working Memory Deficits After Lesions Involving the Supplementary Motor Area

The Supplementary Motor Area (SMA)¿located in the superior and medial aspects of the superior frontal gyrus¿is a preferential site of certain brain tumors and arteriovenous malformations, which often provoke the so-called SMA syndrome. The bulk of the literature studying this syndrome has focused on two of its most apparent symptoms: contralateral motor and speech deficits. Surprisingly, little attention has been given to working memory (WM) even though neuroimaging studies have implicated the SMA in this cognitive process. Given its relevance for higher-order functions, our main goal was to examine whether WM is compromised in SMA lesions. We also asked whether WM deficits might be reducible to processing speed (PS) difficulties. Given the connectivity of the SMA with prefrontal regions related to executive control (EC), as a secondary goal we examined whether SMA lesions also hampered EC. To this end, we tested 12 patients with lesions involving the left (i.e., the dominant) SMA. We also tested 12 healthy controls matched with patients for socio-demographic variables. To ensure that the results of this study can be easily transferred and implemented in clinical practice, we used widely-known clinical neuropsychological tests: WM and PS were measured with their respective Wechsler Adult Intelligence Scale indexes, and EC was tested with phonemic and semantic verbal fluency tasks. Non-parametric statistical methods revealed that patients showed deficits in the executive component of WM: they were able to sustain information temporarily but not to mentally manipulate this information. Such WM deficits were not subject to patients' marginal PS impairment. Patients also showed reduced phonemic fluency, which disappeared after controlling for the influence of WM. This observation suggests that SMA damage does not seem to affect cognitive processes engaged by verbal fluency other than WM. In conclusion, WM impairment needs to be considered as part of the SMA syndrome. These findings represent the first evidence about the cognitive consequences (other than language) of damage to the SMA. Further research is needed to establish a more specific profile of WM impairment in SMA patients and determine the consequences of SMA damage for other cognitive functions

Severity of Dementia, Anosognosia, and Depression in Relation to the Quality of Life of Patients With Alzheimer Disease: Discrepancies Between Patients and Caregivers

Objective: To investigate the factors associated with discrepancies between patient and caregiver reports of the quality of life of patients (QoLp) with Alzheimer¿s disease (AD). Methods: Cross-sectional analytic study of 141 patients and their caregivers. The instruments used were the Quality of Life in AD (QoL-AD), the Global Deterioration Scale (GDS), the Geriatric Depression Scale (GDS-d) and the Anosognosia Questionnaire¿Dementia (AQ-D). Differences were analyzed according to GDS stage. A linear regression analysis was conducted using the difference between the absolute QoLp scores of patients and caregivers. A cluster analysis involving the patient variables was then performed. Results: The discrepancy between patient and caregiver QoLp ratings increased in line with GDS stages (χ2 (2) = 8.7, p = 0.013). In the regression model (F [7,133] = 16.6, p <0.001; R2 = 0.477), discrepancies in QoLp reports were associated with greater anosognosia, less depression and a better cognitive status in patients, as well as with female gender among caregivers. The cluster analysis showed that patients with the lowest ratings of QoLp had a better cognitive status, more depression and less anosognosia. Conversely, the highest ratings were given by patients with a poorer cognitive status, less depression and greater anosognosia. Conclusions: The factors associated with greater discrepancies between patient and caregiver ratings of QoLp were severity of dementia, anosognosia, depression and cognitive status in patients, and female gender in caregivers. In patients with advanced dementia, greater anosognosia leads to more positive ratings in QoLp and complementary observations are required

Circulating progenitor cells during exercise, muscle electro-stimulation and intermittent hypobaric hypoxia in patients with traumatic brain injury. A pilot study

BACKGROUND: Circulating progenitor cells (CPC) treatments may have great potential for the recovery of neurons and brain function. OBJECTIVE: To increase and maintain CPC with a program of exercise, muscle electro-stimulation (ME) and/or intermittent-hypobaric-hypoxia (IHH), and also to study the possible improvement in physical or psychological functioning of participants with Traumatic Brain Injury (TBI). METHODS: Twenty-one participants. Four groups: exercise and ME group (EEG), cycling group (CyG), IHH and ME group (HEG) and control group (CG). Psychological and physical stress tests were carried out. CPC were measured in blood several times during the protocol. RESULTS: Psychological tests did not change. In the physical stress tests the VO2 uptake increased in the EEG and the CyG, and the maximal tolerated workload increased in the HEG. CPC levels increased in the last three weeks in EEG, but not in CyG, CG and HEG. CONCLUSIONS: CPC levels increased in the last three weeks of the EEG program, but not in the other groups and we did not detect performed psychological test changes in any group. The detected aerobic capacity or workload improvement must be beneficial for the patients who have suffered TBI, but exercise type and the mechanisms involved are not clear

Speech segmentation in aphasia

Background: Speech segmentation is one of the initial and mandatory phases of language learning. Although some people with aphasia have shown a preserved ability to learn novel words, their speech segmentation abilities have not been explored. Aims: We examined the ability of individuals with chronic aphasia to segment words from running speech via statistical learning. We also explored the relationships between speech segmentation and aphasia severity, and short-term memory capacity. We further examined the role of lesion location in speech segmentation and short-term memory performance. Methods & Procedures: The experimental task was first validated with a group of young adults (n = 120). Participants with chronic aphasia (n = 14) were exposed to an artificial language and were evaluated in their ability to segment words using a speech segmentation test. Their performance was contrasted against chance level and compared to that of a group of elderly matched controls (n = 14) using group and case-by-case analyses. Outcomes & Results: As a group, participants with aphasia were significantly above chance level in their ability to segment words from the novel language and did not significantly differ from the group of elderly controls. Speech segmentation ability in the aphasic participants was not associated with aphasia severity although it significantly correlated with word pointing span, a measure of verbal short-term memory. Case-by-case analyses identified four individuals with aphasia who performed above chance level on the speech segmentation task, all with predominantly posterior lesions and mild fluent aphasia. Their short-term memory capacity was also better preserved than in the rest of the group. Conclusions: Our findings indicate that speech segmentation via statistical learning can remain functional in people with chronic aphasia and suggest that this initial language learning mechanism is associated with the functionality of the verbal short-term memory system and the integrity of the left inferior frontal region

Factors associated with the variability in caregiver assessments of the capacities of the patients with Alzheimer"s disease

Abstract Background: Several studies have identified certain caregiver factors that can produce variability in their assessments of the capacities of patients with Alzheimer"s disease (AD). Objectives: To identify the caregiver variables associated with variability in their ratings of patients" capacities. Methods: Consecutive sample of 221 out-patients with AD and their family caregivers. The capacities evaluated by caregivers were: the degree of functional disability, using the Disability Assessment for Dementia (DAD); psychological and behavioral symptoms, via the Neuropsychiatric Inventory (NPI); anosognosia, with the Anosognosia Questionnaire Dementia (AQ-D); and quality of life, using the Quality of Life in AD (QOL-AD). The relationship between these measures and caregiver gender, burden, depression, and health was analyzed by means of a bivariate analysis, calculating the effect size (Cohen"s d), and subsequently by a regression analysis, calculating the contribution coefficient (CC). Results: The greatest variability in caregiver assessments was observed in relation to patients with early-stage dementia, where caregiver burden was the main factor associated with a more negative evaluation (d = 1.02 to 1.25). Depression in the caregiver was associated with less variability and only in the assessments of patients with moderate dementia (d = 0.38 to 0.69). In the regression analysis, caregiver factors were associated with greater variance in scores on the NPI (CC = 37.4%) and QOL-AD (CC = 27.2%), and lower variance in AQ-D (CC = 21.6%) and DAD (CC = 10.3%) scores. Conclusions: Caregiver burden and depression were associated with more negative assessments of patients" psychological and behavioral symptoms and quality of life. Key words: Alzheimer"s disease, family caregivers, functional capacity, neuropsychiatric symptoms, anosognosia, quality of life

Novel word acquisition in aphasia: Facing the word-referent ambiguity of natural language learning contexts

Recent research suggests that some people with aphasia preserve some ability to learn novel words and to retain them in the long-term. However, this novel word learning ability has been studied only in the context of single word-picture pairings. We examined the ability of people with chronic aphasia to learn novel words using a paradigm that presents new word forms together with a limited set of different possible visual referents and requires the identification of the correct word-object associations on the basis of online feedback. We also studied the relationship between word learning ability and aphasia severity, word processing abilities, and verbal short-term memory. We further examined the influence of gross lesion location on new word learning. The word learning task was first validated with a group of forty-five young adults. Fourteen participants with chronic aphasia were administered the task and underwent tests of immediate and long-term recognition memory at 1 week. Their performance was compared to that of a group of fourteen matched controls using growth curve analysis. The learning curve and recognition performance of the aphasia group was significantly below the matched control group, although above-chance recognition performance and case-by-case analyses indicated that some participants with aphasia had learned the correct word-referent mappings. Verbal short-term memory but not word processing abilities predicted word learning ability after controlling for aphasia severity. Importantly, participants with lesions in the left frontal cortex performed significantly worse than participants with lesions that spared the left frontal region both during word learning and on the recognition tests. Our findings indicate that some people with aphasia can preserve the ability to learn a small novel lexicon in an ambiguous word-referent context. This learning and recognition memory ability was associated with verbal short-term memory capacity, aphasia severity and the integrity of the left inferior frontal region