Visual attention and perception in patients with Huntington's disease: Comparisons with other subcortical and cortical dementias

Abstract

Shifts in attention were examined in patients with Huntington's disease (HD) using a divided attention paradigm that involved the presentation of global-local stimuli. The HD patients' pattern of performance was compared to the previously reported results of groups of patients with Alzheimer's disease (AD; Filoteo et al., 1992) or Parkinson's disease (PD; Filoteo et al., 1994). Across consecutive trials of the divided attention task, a visual target could appear at either the same global-local level or at a different level. When the target changed levels across consecutive trials, the AD patients demonstrated an impairment in disengaging attention from the level at which the last target appeared, whereas the PD patients were impaired in maintaining their attention at the previously attended level. In contrast to these patterns of performances, the HD patients did not demonstrate a significant impairment in shifting attention between hierarchical levels. Both the AD and the PD patients' abnormal shifting ability was significantly related to the number of errors they made in identifying target stimuli; however, the pattern of the relationship was qualitatively distinct. These results suggest that different attentional mechanisms may underlie AD and PD patients' visual-perceptual deficits. The HD patients' shifting ability was not related to the number of errors they made in identifying target stimuli, suggesting that a different mechanism may account for the visual-perceptual impairments exhibited by these patients.

Normal and Pathological Aging of Attention in Presymptomatic Huntington’s, Huntington’s and Alzheimer’s Disease, and Nondemented Elderly Subjects

“…This suggests that abnormalities observed in HD are manifestations of the pathological process of the illness. HD patients have shown deficits in engaging attention [21] and our findings in HD patients are in agreement with these results [21]. …”

“…Posner and Petersen postulated three types of operations involved in visual attention: disengaging, shifting and engaging [18]. These have been studied in AD and Huntington’s disease (HD) [19,20,21]. …”

“…In contrast to normal aging, damage to subcortical frontal circuits would lead to an alteration of the endogenous attention anterior network, and preservation of the exogenous attention posterior network. In AD, progressive degeneration occurs simultaneously in multimodal association cortex, with impairment of posterior and anterior attentional networks, thus affecting both endogenous and exogenous attention [21]. …”

Shifting attention to different levels within global-local stimuli: A study of normal participants and a patient with temporal-parietal lobe damage

“…One method of examining such intra-stimulus attentional shifts has been to present participants with global-local stimuli (e.g., a large "S" made up from smaller "E"s; see Figure 1) on two consecutive stimulus presentations and determine their speed in identifying a target on the second stimulus presentation under two different conditions: (1) when the target stays at the same globallocal level on the two consecutive stimulus presentations (e.g., the target is at the global level on the first trial and remains at the global level across the two stimulus presentations); and (2) when the target changes levels on the two consecutive trials (e.g., the target was at the global level on the first trial and changed to the local level on the second trial). Previous studies have indicated that normal participants are significantly faster at identifying a target on the second stimulus presentation if it appears at the same global-local level on two consecutive presentations compared to when the target changes global-local levels across the two presentations (Filoteo et al, 1992(Filoteo et al, , 1994(Filoteo et al, , 1995Lamb & Yund, 1996;Robertson, 1996;Ward, 1982). This level-shifting effect suggests that some sort of facilitation for target identification occurs if the target appears at the recently attended global-local level.…”

Disentangling the Role of Cortico-Basal Ganglia Loops in Top–Down and Bottom–Up Visual Attention: An Investigation of Attention Deficits in Parkinson Disease

“…Finally, they are more prone to interference in the presence of a distractor stimulus compared with normal controls, as measured on a dichotic listening task (Sharpe, 1992). Moreover, several behavioral studies indicate that parkinsonian patients with overall well-preserved cognitive functions may nevertheless be impaired at a variety of visual attention tasks (Filoteo et al, 1995;Wright, Burns, Geffen, & Geffen, 1990;Yamada, Izyuuinn, Schulzer, & Hirayama, 1990) and more specifically at tasks tapping selective attention mechanisms (Cools, Rogers, Barker, & Robbins, 2009;Henik, Singh, Beckley, & Rafal, 1993;Pillon et al, 1989).…”