-
Brain : a Journal of Neurology Feb 2021Vestibular dysfunction, causing dizziness and imbalance, is a common yet poorly understood feature in patients with TBI. Damage to the inner ear, nerve, brainstem,...
Vestibular dysfunction, causing dizziness and imbalance, is a common yet poorly understood feature in patients with TBI. Damage to the inner ear, nerve, brainstem, cerebellum and cerebral hemispheres may all affect vestibular functioning, hence, a multi-level assessment-from reflex to perception-is required. In a previous report, postural instability was the commonest neurological feature in ambulating acute patients with TBI. During ward assessment, we also frequently observe a loss of vertigo sensation in patients with acute TBI, common inner ear conditions and a related vigorous vestibular-ocular reflex nystagmus, suggesting a 'vestibular agnosia'. Patients with vestibular agnosia were also more unbalanced; however, the link between vestibular agnosia and imbalance was confounded by the presence of inner ear conditions. We investigated the brain mechanisms of imbalance in acute TBI, its link with vestibular agnosia, and potential clinical impact, by prospective laboratory assessment of vestibular function, from reflex to perception, in patients with preserved peripheral vestibular function. Assessment included: vestibular reflex function, vestibular perception by participants' report of their passive yaw rotations in the dark, objective balance via posturography, subjective symptoms via questionnaires, and structural neuroimaging. We prospectively screened 918 acute admissions, assessed 146 and recruited 37. Compared to 37 matched controls, patients showed elevated vestibular-perceptual thresholds (patients 12.92°/s versus 3.87°/s) but normal vestibular-ocular reflex thresholds (patients 2.52°/s versus 1.78°/s). Patients with elevated vestibular-perceptual thresholds [3 standard deviations (SD) above controls' average], were designated as having vestibular agnosia, and displayed worse posturography than non-vestibular-agnosia patients, despite no difference in vestibular symptom scores. Only in patients with impaired postural control (3 SD above controls' mean), whole brain diffusion tensor voxel-wise analysis showed elevated mean diffusivity (and trend lower fractional anisotropy) in the inferior longitudinal fasciculus in the right temporal lobe that correlated with vestibular agnosia severity. Thus, impaired balance and vestibular agnosia are co-localized to the inferior longitudinal fasciculus in the right temporal lobe. Finally, a clinical audit showed a sevenfold reduction in clinician recognition of a common peripheral vestibular condition (benign paroxysmal positional vertigo) in acute patients with clinically apparent vestibular agnosia. That vestibular agnosia patients show worse balance, but without increased dizziness symptoms, explains why clinicians may miss treatable vestibular diagnoses in these patients. In conclusion, vestibular agnosia mediates imbalance in traumatic brain injury both directly via white matter tract damage in the right temporal lobe, and indirectly via reduced clinical recognition of common, treatable vestibular diagnoses.
Topics: Adolescent; Adult; Aged; Agnosia; Brain Injuries, Traumatic; Dizziness; Female; Humans; Male; Middle Aged; Postural Balance; Reflex, Righting; Vestibule, Labyrinth; White Matter; Young Adult
PubMed: 33367536
DOI: 10.1093/brain/awaa386 -
Brain Structure & Function Dec 2022Motor awareness is a complex, multifaceted construct involving the awareness of both (i) one's motor state while executing a movement or remaining still and (ii) one's... (Review)
Review
Motor awareness is a complex, multifaceted construct involving the awareness of both (i) one's motor state while executing a movement or remaining still and (ii) one's motor abilities. The analysis of neurological syndromes associated with motor disorders suggests the existence of various different components which are, however, integrated into a model of motor awareness. These components are: (i) motor intention, namely, a conscious desire to perform an action; (ii) motor monitoring and error recognition, that is, the capacity to check the execution of the action and identify motor errors; and (iii) a general awareness of one's own motor abilities and deficits, that is, the capacity to recognize the general state of one's motor abilities about the performance of specific actions and the potential consequences of motor impairment. Neuroanatomical correlates involving the parietal and insular cortices, the medial and lateral frontal regions, and subcortical structures (basal ganglia and limbic system) support this multi-component model. Specific damage (or disconnections) to these structures results in a number of different disorders in motor awareness, such as anosognosia for hemiplegia and apraxia, and a number of symptoms which are specific to motor intention disorders (e.g., the Anarchic Hand Syndrome and Tourette's Syndrome) or motor monitoring (e.g., Parkinson's and Huntington's diseases). All of these clinical conditions are discussed in the light of a motor awareness model.
Topics: Humans; Functional Laterality; Awareness; Syndrome; Neuropsychological Tests; Agnosia
PubMed: 36064864
DOI: 10.1007/s00429-022-02558-y -
Handbook of Clinical Neurology 2022Selective disorders of auditory speech processing due to brain lesions are reviewed. Over 120 years after the first anatomic report (Dejerine and Sérieux, 1898), fewer... (Review)
Review
Selective disorders of auditory speech processing due to brain lesions are reviewed. Over 120 years after the first anatomic report (Dejerine and Sérieux, 1898), fewer than 80 cumulative cases of generalized auditory agnosia and pure word deafness with documented brain lesions are on record. Most patients (approximately 70%) had vascular lesions. Damage is very frequently bilateral in generalized auditory agnosia, and more frequently unilateral in pure word deafness. In unilateral cases, anatomical disconnection is not a prerequisite, and disorders may be due to functional disconnection. Regardless of whether lesions are unilateral or bilateral, speech processing difficulties emerge in the presence of damage to the superior temporal regions of the language-dominant hemisphere, suggesting that speech input is processed asymmetrically at early stages already. Extant evidence does not allow establishing whether processing asymmetry originates in the primary auditory cortex or in higher associative cortices, nor whether auditory processing in the brainstem is entirely symmetric. Results are consistent with the view that the difficulty in processing auditory input characterized by quick spectral and/or temporal changes is one of the critical dimensions of the disorder. Forthcoming studies should focus on detailed audiologic, neurolinguistic, and neuroanatomic descriptions of each case.
Topics: Agnosia; Aphasia; Auditory Perception; Humans; Language; Language Development Disorders; Speech; Speech Disorders
PubMed: 35964993
DOI: 10.1016/B978-0-12-823493-8.00005-5 -
Neuroscience and Biobehavioral Reviews Aug 2015We describe a new type of agnosia consisting of an impairment in the ability to mentally represent or know what one is feeling. Freud the neurologist coined the term... (Review)
Review
We describe a new type of agnosia consisting of an impairment in the ability to mentally represent or know what one is feeling. Freud the neurologist coined the term "agnosia" in 1891 before creating psychoanalysis in 1895 but the term has not been previously applied to the domain of affective processing. We propose that the concept of "affective agnosia" advances the theory, measurement and treatment of what is now called "alexithymia," meaning "lack of words for emotion." We trace the origin of the alexithymia construct and discuss the strengths and limitations of extant research. We review evidence that the ability to represent and put emotions into words is a developmental achievement that strongly influences one's ability to experience, recognize, understand and use one's own emotional responses. We describe the neural substrates of emotional awareness and affective agnosia and compare and contrast these with related conditions. We then describe how this expansion of the conceptualization and measurement of affective processing deficits has important implications for basic emotion research and clinical practice.
Topics: Affective Symptoms; Agnosia; Animals; Brain; Emotions; Freudian Theory; Humans; Models, Neurological; Self Concept
PubMed: 26054794
DOI: 10.1016/j.neubiorev.2015.06.007 -
Neuropsychologia Jun 2024Facial identity recognition (FIR) is arguably the ultimate form of recognition for the adult human brain. Even if the term prosopagnosia is reserved for exceptionally... (Review)
Review
Facial identity recognition (FIR) is arguably the ultimate form of recognition for the adult human brain. Even if the term prosopagnosia is reserved for exceptionally rare brain-damaged cases with a category-specific abrupt loss of FIR at adulthood, subjective and objective impairments or difficulties of FIR are common in the neuropsychological population. Here we provide a critical overview of the evaluation of FIR both for clinicians and researchers in neuropsychology. FIR impairments occur following many causes that should be identified objectively by both general and specific, behavioral and neural examinations. We refute the commonly used dissociation between perceptual and memory deficits/tests for FIR, since even a task involving the discrimination of unfamiliar face images presented side-by-side relies on cortical memories of faces in the right-lateralized ventral occipito-temporal cortex. Another frequently encountered confusion is between specific deficits of the FIR function and a more general impairment of semantic memory (of people), the latter being most often encountered following anterior temporal lobe damage. Many computerized tests aimed at evaluating FIR have appeared over the last two decades, as reviewed here. However, despite undeniable strengths, they often suffer from ecological limitations, difficulties of instruction, as well as a lack of consideration for processing speed and qualitative information. Taking into account these issues, a recently developed behavioral test with natural images manipulating face familiarity, stimulus inversion, and correct response times as a key variable appears promising. The measurement of electroencephalographic (EEG) activity in the frequency domain from fast periodic visual stimulation also appears as a particularly promising tool to complete and enhance the neuropsychological assessment of FIR.
Topics: Humans; Facial Recognition; Neuropsychological Tests; Prosopagnosia; Recognition, Psychology; Electroencephalography
PubMed: 38522782
DOI: 10.1016/j.neuropsychologia.2024.108865 -
Neuropsychologia May 2018The cognitive organisation of nonverbal auditory knowledge remains poorly defined. Deficits of environmental sound as well as word and visual object knowledge are...
The cognitive organisation of nonverbal auditory knowledge remains poorly defined. Deficits of environmental sound as well as word and visual object knowledge are well-recognised in semantic dementia. However, it is unclear how auditory cognition breaks down in this disorder and how this relates to deficits in other knowledge modalities. We had the opportunity to study a patient with a typical syndrome of semantic dementia who had extensive premorbid knowledge of birds, allowing us to assess the impact of the disease on the processing of auditory in relation to visual and verbal attributes of this specific knowledge category. We designed a novel neuropsychological test to probe knowledge of particular avian characteristics (size, behaviour [migratory or nonmigratory], habitat [whether or not primarily water-dwelling]) in the nonverbal auditory, visual and verbal modalities, based on a uniform two-alternative-forced-choice procedure. The patient's performance was compared to healthy older individuals of similar birding experience. We further compared his performance on this test of bird knowledge with his knowledge of familiar human voices and faces. Relative to healthy birder controls, the patient showed marked deficits of bird call and bird name knowledge but relatively preserved knowledge of avian visual attributes and retained knowledge of human voices and faces. In both the auditory and visual modalities, his knowledge of the avian characteristics of size and behaviour was intact whereas his knowledge of the associated characteristic of habitat was deficient. This case provides further evidence that nonverbal auditory knowledge has a fractionated organisation that can be differentially targeted in semantic dementia.
Topics: Acoustic Stimulation; Aged; Agnosia; Animals; Auditory Perception; Birds; Female; Humans; Knowledge; Male; Middle Aged; Photic Stimulation; Recognition, Psychology; Semantics; Sound
PubMed: 29572063
DOI: 10.1016/j.neuropsychologia.2018.03.024 -
F1000Research 2019Prosopagnosia is an impairment in the ability to recognize faces and can be acquired after a brain lesion or occur as a developmental variant. Studies of prosopagnosia... (Review)
Review
Prosopagnosia is an impairment in the ability to recognize faces and can be acquired after a brain lesion or occur as a developmental variant. Studies of prosopagnosia make important contributions to our understanding of face processing and object recognition in the human visual system. We review four areas of advances in the study of this condition in recent years. First are issues surrounding the diagnosis of prosopagnosia, including the development and evaluation of newer tests and proposals for diagnostic criteria, especially for the developmental variant. Second are studies of the structural basis of prosopagnosia, including the application of more advanced neuroimaging techniques in studies of the developmental variant. Third are issues concerning the face specificity of the defect in prosopagnosia, namely whether other object processing is affected to some degree and in particular the status of visual word processing in light of recent predictions from the "many-to-many hypothesis". Finally, there have been recent rehabilitative trials of perceptual learning applied to larger groups of prosopagnosic subjects that show that face impairments are not immutable in this condition.
Topics: Facial Recognition; Humans; Learning; Neuroimaging; Prosopagnosia
PubMed: 31231507
DOI: 10.12688/f1000research.18492.1 -
Geriatrie Et Psychologie... Mar 2023Impaired awareness increases dependency of patients suffering from Alzheimer's Disease (AD) and caregivers' burden but remains insufficiently evaluated in clinical...
Impaired awareness increases dependency of patients suffering from Alzheimer's Disease (AD) and caregivers' burden but remains insufficiently evaluated in clinical practice. The numerous conceptualisations of this symptomatology (anosognosia, denial, insight…) have only a slight impact on the three main assessment methodologies which are: the patient-caregiver discrepancy; the clinician rating of patients' awareness of illness; and the prediction of performance discrepancy methods. Nevertheless, most of evaluating tools are not validated yet, in particular regarding the clinician rating, leading to contrasted results. Most of recent studies reported positive correlations with apathy and AD severity, and negative relationships with depressive symptoms. Therefore, impaired awareness seems to be mainly influenced by patient's depression and apathy. We discuss these correlates and shared aspects of apathy and impaired awareness from neuroanatomical, clinical and conceptual viewpoints. We also highlight the relevance and limits of quantitative and qualitative assessment methods, in particular phenomenological.
Topics: Humans; Alzheimer Disease; Depression; Neuropsychological Tests; Caregivers; Agnosia
PubMed: 37115686
DOI: 10.1684/pnv.2023.1080 -
Neuropsychological Rehabilitation Dec 2020Developmental prosopagnosia (DP) is a cognitive condition characterised by a relatively selective deficit in face recognition. Some adults and children with DP...
Developmental prosopagnosia (DP) is a cognitive condition characterised by a relatively selective deficit in face recognition. Some adults and children with DP experience severe psychosocial consequences related to the condition, yet are reluctant to disclose it to others. The remediation of DP is therefore an urgent issue, but has been met with little success. Given that developmental conditions may only benefit from compensatory rather than remedial training, this study aimed to examine (a) the positive and negative effects of DP disclosure, and (b) compensatory techniques that may circumvent recognition failure. Qualitative questionnaires and interviews were carried out with 79 participants: 50 adults with DP, 26 of their non-affected significant others, and three parents of DP children. Findings indicated positive effects of disclosure, yet most adults choose not to do so in the workplace. Effective compensatory strategies include the use of extra-facial information, identity prompts from others, and preparation for planned encounters. However, changes in appearance, infrequent contact, or encounters in unexpected contexts often cause strategy failure. As strategies are effortful and disrupted by heavily controlled appearance (e.g., the wearing of uniform), disclosure of DP may be necessary for the safety, wellbeing and optimal education of children with the condition.
Topics: Adaptation, Psychological; Adult; Child; Cognitive Remediation; Female; Humans; Male; Prosopagnosia; Qualitative Research; Self Disclosure; Social Perception; Truth Disclosure
PubMed: 31161896
DOI: 10.1080/09602011.2019.1623824 -
Journal of Clinical Psychopharmacology
Topics: Humans; Psychopharmacology; Agnosia; Alzheimer Disease; Neuropsychological Tests
PubMed: 37126825
DOI: 10.1097/JCP.0000000000001687