-
Brain Sciences Apr 2022Visuo-motor adaptation to optical prisms ( PA), displacing the visual scene laterally, is a behavioral method used for the experimental investigation of visuomotor...
Visuo-motor adaptation to optical prisms ( PA), displacing the visual scene laterally, is a behavioral method used for the experimental investigation of visuomotor plasticity, and, in clinical settings, for temporarily ameliorating and rehabilitating unilateral spatial neglect. This study investigated the building up of PA, and the presence of the typically occurring subsequent (AEs) in a brain-damaged patient (TMA), suffering from apperceptive agnosia and a right visual half-field defect, with bilateral atrophy of the parieto-occipital cortices, regions involved in PA and AEs. Base-Right prisms and control neutral lenses were used. PA was achieved by repeated pointing movements toward three types of stimuli: visual, auditory, and bimodal audio-visual. The presence and the magnitude of AEs were assessed by proprioceptive, visual, visuo-proprioceptive, and auditory-proprioceptive straight-ahead pointing tasks. The patient's brain connectivity was investigated by Diffusion Tensor Imaging (DTI). Unlike control participants, TMA did not show any adaptation to prism exposure, but her AEs were largely preserved. These findings indicate that AEs may occur even in the absence of PA, as indexed by the reduction of the pointing error, showing a dissociation between the classical measures of PA and AEs. In the PA process, error reduction, and its feedback, may be less central to the building up of AEs, than the sensorimotor pointing activity per se.
PubMed: 35448011
DOI: 10.3390/brainsci12040480 -
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 -
Cureus Sep 2023Kluver-Bucy Syndrome (KBS) is a rare neuropsychiatric disorder characterized by hyperorality, hypersexuality, bulimia, visual agnosia, and amnesia due to lesions... (Review)
Review
Kluver-Bucy Syndrome (KBS) is a rare neuropsychiatric disorder characterized by hyperorality, hypersexuality, bulimia, visual agnosia, and amnesia due to lesions affecting bilateral temporal lobes. It is attributed to a multitude of causes, including stroke, herpes simplex encephalitis, Alzheimer's disease, and head trauma. Current treatments for KBS include symptomatic management with antipsychotics, mood stabilizers, carbamazepine, and selective serotonin reuptake inhibitors. The bibliometric analysis was done to reflect the relevance and understanding of KBS in recent literature. The SCOPUS database was utilized to conduct a search for all articles with the terms "Kluver-Bucy" and "Kluver Bucy" from January 1, 1955 (the first available articles from the search) to February 1, 2023. The parameters included in this analysis were article title, citation numbers, citations per year, authors, institutions, publishing journals, country of origin, Source Normalized Impact per Paper, and Scopus CiteScore. Since 1937, when Kluver-Bucy Syndrome was first defined, the publications on KBS have steadily increased, with up to six publications a year in 2002. The most common institutions were SUNY Upstate Medical University, VA Medical Center, and the State University of New York (SUNY) System. Seven of these papers were published in . Almost 75% of the articles were published in journals of medicine and neuroscience. This is the first bibliometric analysis to evaluate the most influential publications about Kluver-Bucy Syndrome. A majority of the research is case-based and there is a dearth of clinical trials to identify the exact pathophysiology and physiotherapy management, possibly owing to the rarity of the disease. Our research suggests that there may be a significant overlap between Sanfilippo syndrome and KBS, suggesting that refined guidelines for establishing diagnosis may be required for children. Our study could bring a renewed interest in this field and lead to additional research focused on understanding the pathophysiology of KBS in order to promote the development of novel diagnostics and treatment.
PubMed: 37854727
DOI: 10.7759/cureus.45382 -
Neurocritical Care Jun 2024Gerstmann syndrome, characterized by a tetrad of symptoms, which are agraphia, acalculia, left-right disorientation, and finger agnosia, presents challenges in both...
Gerstmann syndrome, characterized by a tetrad of symptoms, which are agraphia, acalculia, left-right disorientation, and finger agnosia, presents challenges in both understanding its pathophysiology and establishing effective treatment modalities. Neuroanatomical studies have highlighted the involvement of the dominant parietal lobe, particularly the inferior parietal lobule, in the development of Gerstmann syndrome. Although current treatment options are largely supportive, recent research suggests a potential role for deep brain stimulation (DBS) in managing this condition. DBS, known for its efficacy in various neurological disorders, has been hypothesized to modulate neuronal pathways associated with Gerstmann syndrome. However, clinical evidence supporting DBS in Gerstmann syndrome remains scarce, posing challenges in patient selection and ethical considerations. Future research should prioritize investigating the efficacy and safety of DBS in Gerstmann syndrome to improve patient outcomes and quality of life.
PubMed: 38914905
DOI: 10.1007/s12028-024-02013-2 -
Zhurnal Nevrologii I Psikhiatrii Imeni... 2022FTD is a group of neurodegenerative diseases with progressive deterioration of behavioral and speech disorders, morphologically associated with pathology of the frontal... (Review)
Review
FTD is a group of neurodegenerative diseases with progressive deterioration of behavioral and speech disorders, morphologically associated with pathology of the frontal or temporal lobes. International clinical trials have made it possible to define modern diagnostic criteria for various subtypes of clinically «possible/probable» FTD. Our article is devoted to one of the rare subtypes of frontotemporal dementia (FTD), corticobasal syndrome (CBD), in which we presented a review of current data with a demonstration of clinical observation. A clinical case of a patient with a patient with speech disorders and memory impairment is presented. A 60-year-old man at the time of the outpatient visit had been complaining of speech impairment for two years, a slight decrease in memory for current events. Neurological and neuropsychological studies revealed two leading clinical syndromes in the patient: «frontal» syndrome with impaired higher cortical functions in the form of efferent motor aphasia, impaired writing and reading with visual-spatial agnosia and dysgraphia, «frontal» signs (positive «palm-mouth «and» grasping «reflexes); «Corticobasal syndrome» with pronounced dynamic, optic-kinesthetic dyspraxia, dermolexia, apraxia of closing the eyes, «alien» hand syndrome with symptoms of levitation and intermanual conflict. MRI diagnostics revealed changes characteristic of neurodegeneration of the frontotemporal type (atrophy of the frontal and temporal lobes prevails). Taking into account complaints, anamnesis of the disease, identified clinical syndromes and structural changes according to MRI data, the patient was diagnosed with a clinically «probable» FTD. Determination and accurate diagnosis of FTD subtypes will help the neurologist in managing these patients with the appointment of the correct pharmacologic treatment. In FTD, in contrast to AD patients, the administration of cholinesterase inhibitors does not lead to a positive therapeutic effect a positive therapeutic effect and, therefore, is not advisable. The standards of patient therapy should include recommendations for antipsychotic therapy, the use of antidepressants (SSRIs) and anxiolytics with nootropic effects for the correction of affective and behavioral disorders.
Topics: Frontotemporal Dementia; Humans; Magnetic Resonance Imaging; Male; Middle Aged; Neurodegenerative Diseases; Syndrome; Temporal Lobe
PubMed: 35271245
DOI: 10.17116/jnevro2022122021107 -
Cognitive and Behavioral Neurology :... Mar 2022Anosognosia can manifest as an unawareness of neurobehavioral symptoms in individuals with Huntington disease (HD). Measurement of anosognosia is challenging, but the...
BACKGROUND
Anosognosia can manifest as an unawareness of neurobehavioral symptoms in individuals with Huntington disease (HD). Measurement of anosognosia is challenging, but the Anosognosia Scale (AS) represents a brief option with promising findings in small samples.
OBJECTIVE
To replicate application of the AS in a larger HD sample than previous studies in order to assess psychometrics and demographic correlates and to investigate the genetic, motor, and neuropsychological correlates of the AS in individuals with HD.
METHOD
We retrospectively reviewed the AS ratings of 74 genetically confirmed Huntington gene carriers, nearly all early motor manifest, who had been referred for clinical neuropsychological assessment. Concurrent clinical neurologic examination and neuropsychometric assessment data were compiled, where available (ns = 35-74). The severity of the anosognosia per AS ratings was characterized for the HD sample.
RESULTS
The AS ratings did not correlate with demographic variables, genetic markers, or motor dysfunction severity. Correlation analyses revealed that higher AS ratings correlated with worse recognition-discrimination memory performance (r = 0.38, P < 0.05) but not cognitive control on executive functioning performance or on collateral-reported frontal-behavioral symptoms. Higher AS ratings also correlated with fewer patient-reported depressive symptoms (r = -0.38, P < 0.01) and diurnal hypersomnia symptoms (r = -0.44, P < 0.01).
CONCLUSION
Anosognosia (per AS) is associated with recognition-discrimination deficits and fewer self-reported neuropsychiatric symptoms in individuals with pre-to-early manifest HD, though not with HD severity per genetic or motor markers, nor to executive dysfunction or collateral-reported frontal-behavioral symptoms.
Topics: Agnosia; Cognitive Dysfunction; Executive Function; Humans; Huntington Disease; Neuropsychological Tests; Retrospective Studies
PubMed: 35239598
DOI: 10.1097/WNN.0000000000000293 -
Handbook of Clinical Neurology 2021Face recognition is a form of expert visual processing. Acquired prosopagnosia is the loss of familiarity for facial identity and has several functional variants, namely...
Face recognition is a form of expert visual processing. Acquired prosopagnosia is the loss of familiarity for facial identity and has several functional variants, namely apperceptive, amnestic, and associative forms. Acquired forms are usually caused by either occipitotemporal or anterior temporal lesions, right or bilateral in most cases. In addition, there is a developmental form, whose functional and structural origins are still being elucidated. Despite their difficulties with recognizing faces, some of these subjects still show signs of covert recognition, which may have a number of explanations. Other aspects of face perception can be spared in prosopagnosic subjects. Patients with other types of face processing difficulties have been described, including impaired expression processing, impaired lip-reading, false familiarity for faces, and a people-specific amnesia. Recent rehabilitative studies have shown some modest ability to improve face perception in prosopagnosic subjects through perceptual training protocols.
Topics: Facial Recognition; Humans; Prosopagnosia; Recognition, Psychology; Visual Perception
PubMed: 33832676
DOI: 10.1016/B978-0-12-821377-3.00006-4 -
Brain : a Journal of Neurology Feb 2023Neurodevelopmental disorders are categorized and studied according to their manifestations as distinct syndromes. For instance, congenital prosopagnosia and dyslexia...
Neurodevelopmental disorders are categorized and studied according to their manifestations as distinct syndromes. For instance, congenital prosopagnosia and dyslexia have largely non-overlapping research literatures and clinical pathways for diagnosis and intervention. On the other hand, the high incidence of neurodevelopmental comorbidities or co-existing extreme strengths and weaknesses suggest that transdiagnostic commonalities may be greater than currently appreciated. The core-periphery model holds that brain regions within the stable core perceptual and motor regions are more densely connected to one another compared to regions in the flexible periphery comprising multimodal association regions. This model provides a framework for the interpretation of neural data in normal development and clinical disorders. Considering network-level commonalities reported in studies of neurodevelopmental disorders, variability in multimodal association cortex connectivity may reflect a shared origin of seemingly distinct neurodevelopmental disorders. This framework helps to explain both comorbidities in neurodevelopmental disorders and profiles of strengths and weaknesses attributable to competitive processing between cognitive systems within an individual.
Topics: Humans; Neurodevelopmental Disorders; Brain; Cerebral Cortex; Dyslexia; Prosopagnosia; Magnetic Resonance Imaging; Neural Pathways
PubMed: 36299249
DOI: 10.1093/brain/awac387