The closing-in phenomenon in Parkinson's disease

Visual Dysfunction in Parkinson's Disease

Non-motor symptoms in Parkinson's disease (PD) include ocular, visuoperceptive, and visuospatial impairments, which can occur as a result of the underlying neurodegenerative process. Ocular impairments can affect various aspects of vision and eye movement. Thus, patients can show dry eyes, blepharospasm, reduced blink rate, saccadic eye movement abnormalities, smooth pursuit deficits, and impaired voluntary and reflexive eye movements. Furthermore, visuoperceptive impairments affect the ability to perceive and recognize visual stimuli accurately, including impaired contrast sensitivity and reduced visual acuity, color discrimination, and object recognition. Visuospatial impairments are also remarkable, including difficulties perceiving and interpreting spatial relationships between objects and difficulties judging distances or navigating through the environment. Moreover, PD patients can present visuospatial attention problems, with difficulties attending to visual stimuli in a spatially organized manner. Moreover, PD patients also show perceptual disturbances affecting their ability to interpret and determine meaning from visual stimuli. And, for instance, visual hallucinations are common in PD patients. Nevertheless, the neurobiological bases of visual-related disorders in PD are complex and not fully understood. This review intends to provide a comprehensive description of visual disturbances in PD, from sensory to perceptual alterations, addressing their neuroanatomical, functional, and neurochemical correlates. Structural changes, particularly in posterior cortical regions, are described, as well as functional alterations, both in cortical and subcortical regions, which are shown in relation to specific neuropsychological results. Similarly, although the involvement of different neurotransmitter systems is controversial, data about neurochemical alterations related to visual impairments are presented, especially dopaminergic, cholinergic, and serotoninergic systems.

Frontal defect contribution to decreasing of body mass index in Parkinson's disease patients

OBJECTIVE

Weight loss is common in patients with Parkinson's disease (PD). It has been reported that low Body Mass Index (BMI) is associated with disease progression in these patients, but only a few data are available on the relationship between BMI and cognitive dysfunctions in PD patients. In the present study we systematically assessed the possible relationship between BMI index and specific cognitive defects.

METHOD

We enrolled a prospective sample of 37 PD individuals and 30 healthy controls (HC) of similar age, sex, and education. The BMI was calculated in each participant, who underwent a neuropsychological assessment exploring the general cognitive skills, frontal/executive, visuo-spatial, visuo-constructional and memory abilities.

RESULTS

We showed that PD group had significant lower BMI value compared to HC group. In PD patients, the BMI was negatively correlated to disease duration and number of errors at the Stroop-Color Word Test, and positively to score on Frontal Assessment Battery (FAB). Moreover, a regression analysis revealed that, the BMI in PD patients was associated with disease duration and score on FAB.

CONCLUSIONS

Our findings contribute to reveal that the relationship between height and weight is strongly related to frontal cognitive dysfunctions in PD patients.

Constructional apraxia from the roots up: Kleist, Strauss, and their contemporaries

The concept and the term of constructional apraxia have been proposed by Karl Kleist and described in his impressive book "Gehirnpathologie", published in 1934. However, the first ever paper under the heading of constructional apraxia was written by Hans Strauss, one of Kleist's pupils, and published in 1924. Nowadays, the term constructional apraxia is still in use to refer to all disorders observed in drawing and assembling activities; its assessment, performed as it was in early studies, is part of common practice in behavioral neurology and neuropsychology. Nonetheless, the concept and the neural underpinnings of constructional apraxia have been deeply revisited with respect to the original proposal. Modern studies demonstrated that drawing and assembling are based on very large and complex brain networks extending in both hemispheres, including the left angular gyrus (as hypothesized by Kleist) but well beyond the original ideas about localization of constructional apraxia. From a clinical point of view, constructional apraxia has poor localizing value but provides valuable diagnostic information for conditions of cognitive impairment.

Closing-in Phenomenon in Huntington's Disease: A Neuropsychological Marker of Frontal/Executive Dysfunction

Objective

In visuo-constructional tasks, patients may reproduce drawings near-to or superimposed on a model, showing the so-called "Closing-in" (CI), often ascribed to a defect in inhibitory control. CI has been described in neurological conditions, but no studies have explored CI in Huntington's disease (HD), a neurodegenerative disorder often involving the frontal cortical-subcortical circuits. We searched for the occurrence of CI in HD patients and systematically investigated its correlates to find a clinical marker of the frontal/executive dysfunctions in the early examination of HD patients.

Method

We assessed 130 HD participants, who performed a graphic coping task and a neuropsychological, psychiatric, motor, and functional assessment.

Results

CI occurred in 52/130 (40%) HD patients, with 43/52 (82.7%) superimposing their copy directly on the model. MANOVA showed that HD patients with CI scored significantly poorer on Symbol digit modality test, Stroop-color word - reading test, Stroop-color word - interference test, Trail making test - part B, and Phonological verbal fluency test. However, a logistic regression analysis revealed that the significant predictor of the occurrence of CI was the score on Stroop-color word - interference test.

Conclusions

HD patients may show CI in graphic tasks, and it could be related to a defect in inhibitory control impeding the switch of attention from the model to the copying space, and releasing a default tendency which causes an attraction of hand movement towards the focus of visual attention. CI might be a useful clinical marker for the early detection of frontal/executive defects in HD patients.

Closing-in Behavior and Parietal Lobe Deficits: Three Single Cases Exhibiting Different Manifestations of the Same Behavior

Closing-in behavior (CIB) is observed in copying tasks (graphic or gestural) when the copy is performed near or on the top of the model. This symptom has been classically considered to be a manifestation of constructional apraxia and is often associated with a visuospatial impairment. More recent work emphasizes the attentional and/or executive nature of the behavior and its association with frontal lobe dysfunction. We describe three patients in whom CIB was associated with posterior parietal deficits of different etiologies (stroke in Patient 1 and dementia in Patients 2 and 3). In copying figures, Patient 1 produced the shape with high accuracy but the rendering overlapped the model, while for Patients 2 and 3 the copies were distorted but overlapping or in close proximity to the target. In gesture imitation, Patient 2 performed the gestures toward the examiner's space, while Patient 1 showed a peculiar form of CIB: when he was asked to place the ipsilesional arm in a position that mirrored the contralesional hand, Patient 1 moved his hand toward his contralesional hand. Patient 3 did not present gestural CIB. While CIB in Patient 1 was associated with selective deficits in executive functions and attention, additional visuospatial deficits were observed in Patients 2 and 3. The latter two patients showed a general visuoconstructional deficit. These case studies support a primary attentional account of CIB but also suggest that visuoconstructional impairments may contribute to the emergence of CIB, in some subjects. This evidence argues for different types of CIB with different cognitive and neural underpinnings. Furthermore, the data support the hypothesis of a differential involvement of fronto-parietal network in CIB.

Parietal Involvement in Constructional Apraxia as Measured Using the Pentagon Copying Task

Deficits in copying ("constructional apraxia") is generally defined as a multifaceted deficit. The exact neural correlates of the different types of copying errors are unknown. To assess whether the different categories of errors on the pentagon drawing relate to different neural correlates, we examined the pentagon drawings of the MMSE in persons with subjective cognitive complaints, mild cognitive impairment, or early dementia due to Alzheimer's disease. We adopted a qualitative scoring method for the pentagon copy test (QSPT) which categorizes different possible errors in copying rather than the dichotomous categories "correct" or "incorrect." We correlated (regional) gray matter volumes with performance on the different categories of the QSPT. Results showed that the total score of the QSPT was specifically associated with parietal gray matter volume and not with frontal, temporal, and occipital gray matter volume. A more fine-grained analysis of the errors reveals that the intersection score and the number of angles share their underlying neural correlates and are associated with specific subregions of the parietal cortex. These results are in line with the idea that constructional apraxia can be attributed to the failure to integrate visual information correctly from one fixation to the next, a process called spatial remapping.

The Closing-In Phenomenon in an Ecological Walking Task

OBJECTIVES

Alzheimer's disease (AD) patients may show the Closing-in (CI), a tendency to reproduce figures close to or superimposed on the model. AD patients with CI might manifest reduced functional independence compared to AD patients without CI, but no study directly assessed if CI can hamper common daily living activities. To address this issue here we investigated whether AD patients with CI veer their walking trajectory toward irrelevant objects more often than AD patients without CI.

METHODS

Fifty AD individuals, and 20 age- and education-matched healthy adults, underwent a graphic copying task to detect CI and a newly developed walking task to assess the tendency to veer toward irrelevant objects and to bump into them. All participants also completed a comprehensive neuropsychological battery to assess dementia severity; impairments in frontal/executive, visuo-spatial, visuo-constructional, and memory domains; and functional independence in daily living activities.

RESULTS

Graphic CI occurred in 34/50 (68%) AD patients (AD-CI group) who achieved significantly lower scores on frontal/executive abilities, and daily living functioning than AD individuals not showing CI. Most AD-CI patients (20/34; 58.8%) also showed at least one veering error in the walking task. Participants with CI and veering errors showed significantly poorer performance on Stroop test, and lower level of functional independence than AD individuals with CI in isolation.

CONCLUSIONS

CI on graphic tasks can identify difficulties in walking and in complying with everyday activities in AD patients. These observations demonstrate the value of assessing CI in copying tasks. (JINS, 2018, 24, 437-444).

Cognitive and behavioral disorders in Parkinson's disease: an update. I: cognitive impairments

Parkinson's disease (PD) is a progressive neurodegenerative disease characterized by motor symptoms such as rigidity, rest tremor, and bradykinesia. However, a growing body of evidence demonstrated that PD encompasses several non-motor disturbances as well, such as cognitive impairment. Cognitive defects can be present since early stages of the disease but tend to dominate the clinical picture as the disease progresses. Around 40% of patients with PD present with cognitive impairments in several cognitive domains including attention, working memory and executive functions, language, visuospatial skills, and episodic memory; in later stages of the disease, cognitive defects and associated behavioral disorders concur to determine clinically relevant PD-associated dementia. Part of these defects is ascribed to a dopamine-dependent dysfunction of fronto-striatal pathways, but there is a considerable heterogeneity in the cognitive impairments as well as a suggestion of the role of other neurotransmitter systems, such as the cholinergic one, mainly responsible for Parkinson-dementia syndrome. In this paper, we review recent literature with particular attention to the last 5 years on the main cognitive deficits described in PD patients as well as on the hypothesized neuro-functional substrate of such impairments. Finally, we provide some suggestions on how to test cognitive functions in PD appropriately.

Drawing Disorders in Alzheimer's Disease and Other Forms of Dementia

Drawing is a multicomponential process that can be impaired by many kinds of brain lesions. Drawing disorders are very common in Alzheimer's disease and other forms of dementia, and can provide clinical information for the distinction of the different dementing diseases. In our review we started from an overview of the neural and cognitive bases of drawing, and from a recollection of the drawing tasks more frequently used for assessing individuals with dementia. Then, we analyzed drawing disorders in dementia, paying special attention to those observed in Alzheimer's disease, from the prodromal stages of the amnesic mild cognitive impairment to the stages of full-blown dementia, both in the sporadic forms with late onset in the entorhino-hippocampal structures and in those with early onset in the posterior neocortical structures. We reviewed the drawing features that could differentiate Alzheimer's disease from vascular dementia and from the most frequent forms of degenerative dementia, namely frontotemporal dementia and Lewy body disease. Finally, we examined some peculiar aspects of drawing disorders in dementia, such as perseverations, rotations, and closing-in. We argue that a careful analysis of drawing errors helps to differentiate the different forms of dementia more than overall accuracy in drawing.