Dissociation in the recovery from neglect dyslexia and visuospatial unilateral neglect: a case report

The recovery of the ability to read of a patient affected by persistent visuospatial neglect suggests the functional independence of the two phenomena. Neglect dyslexia seems to be an example of a dissociation between an implicit and explicit knowledge of the characteristics of the stimulus.

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Sommario Il recupero della capacità di lettura in un paziente con persistente neglect visuo-spaziale suggerisce l'indipendenza funzionale dei due fenomeni. La neglect dyslexia sembra costituire un esempio di dissociazione tra conoscenza implicita ed esplicita delle caratteristiche dello stimolo.

     

The modular architecture of the neglect syndrome: Implications for action control in visual neglect

In our recent review of action control deficits in hemispatial neglect we concluded that many patients with the disorder have deficits in visuomotor control [Coulthard, E., Parton, A., & Husain, M. (2006). Action control in visual neglect. Neuropsychologia, 44(13), 2717-2733]. This conclusion has been questioned and it has been argued instead that there are no action deficits in neglect [Himmelbach, M., Karnath, H.-O., & Perenin, M.-T. (2007). Action control is not affected by spatial neglect: A comment on Coulthard et al. Neuropsychologia, 45(8), 1979-1981]. We proposed that rather than being specific to the neglect syndrome, action control deficits are more likely to relate to lesion location. Although many of these impairments may contribute to the manifestation of neglect, they may also occur in brain-damaged patients without the condition. In this article, we explore this framework further, discussing how neglect behaviour may emerge from damage to a set of visuomotor or cognitive modules, or their connections. Central to our view is the idea that the critical combination of deficits leading to neglect varies considerably between cases, and that visuomotor or cognitive modules disrupted in the syndrome may not, in fact, be specific to neglect.     

The cause of child abuse and neglect and their effects on the development of children in Samaru Zaria, Nigeria

Every child despite his individual differences and uniqueness is to be considered of equal worth. He should therefore be entitled to equal social, economic, civil and political rights, so that he may fully realise his inherent potential and share equally in life (Gill, 1979).

Obviously, these values are rooted in the humanistic philosophy of any nation's declaration of independence. In accordance with these value premises therefore “any act of commission or ommission by individuals, institutions or the society as a whole, and any conditions which deprive children of equal rights and liberties and interfere with their optimal development, constitutes by definition abuse or neglectful acts or conditions” (Gill, 1979).

Child abuse is a significant contemporary community problem. Although children have been maltreated throughout history, our community has been silent in defence of abused children. Child abuse is not a phenomenon of the 20th Century nor is it unique to our society and culture alone. It has occurred throughout the recorded history of man. The future of any nation depends on its children and their capabilities. For this reason, they must be given a full chance.     

Insults to the body civil: Mistreatment of elderly in two Plains Indian tribes

The mistreatment of elderly is subject to various social constructions. On two geographically distinct Plains Indian Reservations which we call Lone Mountain and Abundant Lands, the abuse or neglect of elderly is construed as a health problem which is a dysfunction of the community as a whole. Both physical abuse and neglect are more common on the Lone Mountain Reservation, occurring in association with other indicators of community disorganization such as unemployment and substance abuse. On the Abundant Lands Reservation physical abuse was categorically denied and what neglect existed appeared to be a function of role strain, geographic dispersal, climate and terrain. We attribute differences in the prevalence of mistreatment of elders to variations in economic opportunities for younger residents. Examining the historical and present contexts of intergenerational relationships on the reservations, we discuss the implications of this study for social exchange theory and policy applications.This research was supported by the Gerontological Society of America AppliedThis research was supported by the Gerontological Society of America AppliedThis research was supported by the Gerontological Society of America AppliedThis research was supported by the Gerontological Society of America AppliedThis research was supported by the Gerontological Society of America AppliedThis research was supported by the Gerontological Society of America Applied     

Effects of cueing on visuospatial processing in unilateral spatial neglect

Patients with typical left unilateral spatial neglect bisected lines after cueing to the left end-point, the fixation point being monitored with an eye camera. They persisted with the point of initial fixation made after cueing and placed the mark there without searching leftwards again. The rightward shift of fixation to the initial point of fixation thus determined the location of the subjective midpoint. We consider that rightward attentional bias increased the amplitude of this shift that was planned on the basis of the perception of the whole line while cueing. This hypothesis may explain smaller but obvious rightward bisection errors found in the cueing condition.     

Degree of Somatoform and Psychological Dissociation in Dissociative Disorder Is Correlated with Reported Trauma

In this study, the prevalence and severity of traumatic experiences as reported by patients with dissociative disorders and with other DSM-IV psychiatric diagnoses were compared. Furthermore, the predictive value of emotional, physical, and sexual trauma with respect to somatoform and psychological dissociation was analyzed. In contrast with comparison patients, dissociative disorder patients reported severe and multifaceted traumatization. Physical and sexual trauma predicted somatoform dissociation, sexual trauma predicted psychological dissociation as well. According to the memories of the dissociative disorder patients, this abuse occurred in an emotionally neglectful and abusive social context. Pathological dissociation was best predicted by early onset of reported intense, chronic and multiple traumatization. Methodological limitations restricting causal inferences between reported trauma and dissociation are discussed.     

Identification of the central vestibular projections in man: a positron emission tomography activation study

The cerebral representation of space depends on the integration of many different sensory inputs. The vestibular system provides one such input and its dysfunction can cause profound spatial disorientation. Using positron emission tomography (PET), we measured regional cerebral perfusion with various vestibular stimulations to map central vestibular projections and to investigate the cerebral basis of spatial disorientation. We showed that the temporoparietal cortex, the insula, the putamen, and the anterior cingulate cortex are the cerebral projections of the vestibular system in man and that the spatial disorientation caused by unilateral vestibular stimulation is associated with their asymmetric activation.     

Influence of response modality on awareness of contralesional tactile stimuli in right brain damaged patients

Thirty right brain-damaged (RBD) patients with left tactile extinction (19 of whom also showed neglect) were given a sequence of 240 tactile stimuli – 80 right, 80 left, 80 bilateral – across 4 different response conditions: (a) verbal report of stimulated side/s, (b) motor report of stimulated side/s, (c) verbal report of unstimulated side/s, (d) motor report of unstimulated side/s. Earlier experiments based on similar tasks but involving RBD patients with visual extinction and/or neglect have shown that visual awareness of contralesional stimuli can be influenced by manipulation of response conditions.

Since neglect and extinction can be double-dissociated both anatomically and behaviourally, the question arises of whether the underlying neuronal mechanisms are different. To answer this question the present work investigated the role of perceptual and premotor factors in generating tactile extinction in response to Double Simultaneous Stimulation (DSS). The hypothesis was that a directional response bias would result in an overall higher frequency of errors for verbal or motor responses indicating the ipsilesional side (right); a perceptual bias would instead result in errors distributed with similar frequency on the ipsilesional and the contralesional (left) side.

Results showed that, in RBD patients, contralesional extinction was not influenced by response conditions (verbal/motor; report of stimulated/unstimulated side) and presence/absence of neglect. This suggests that: (1) among RBD patients, directional response biases are unlikely to play a role in extinction of tactile stimuli on DSS; (2) the mechanisms underlying extinction are, at least to some extent, different from those underlying unilateral neglect.     

Hypermnesia in unilateral neglect

Thirteen right brain-damaged patients who were found to neglect pictures presented on the left of a display were presented the same stimuli, intermixed with foils, in a yes-no recognition test. Fifty per cent of patients claimed to have already seen one or more of the previously neglected pictures. This demonstrates that visual information that fails to access consciousness in neglect patients does retain the ability to surface as explicit memory at a later stage.     

Visuospatial representation in patients with mild cognitive impairment: Implication for rehabilitation

Behavioral and neurophysiological experiments have demonstrated that distinct and common cognitive processes and associated neural substrates maintain allocentric and egocentric spatial representations. This review aimed to provide evidence from previous behavioral and neurophysiological studies on collating cognitive processes and associated neural substrates and linking them to the state of visuospatial representations in patients with mild cognitive impairment (MCI). Even though MCI patients showed impaired visuospatial attentional processing and working memory, previous neuropsychological experiments in MCI largely emphasized memory impairment and lacked substantiating evidence of whether memory impairment could be associated with how patients with MCI encode objects in space. The present review suggests that impaired memory capacity is linked to impaired allocentric representation in MCI patients. This review indicates that further research is needed to examine how the decline in visuospatial attentional resources during allocentric coding of space could be linked to working memory impairment.