A Review: Visuospatial Dysfunction in Patients with the Cerebral Small Vessel Disease.

Cerebral small vessel disease (CSVD) impairs visuospatial function, and this is one of the most obvious areas of cognitive impairment in CSVD. So, recognizing, monitoring, and treating visuospatial dysfunction are all important to the prognosis of CSVD. This review discussed the anatomical and pathological mechanisms, clinical recognition (scales, imaging, and biomarkers), and treatment of cognitive impairment especially visuospatial dysfunction in CSVD.

Is Shadowing Behavior Caused by Body Representation Disorders and Apraxia?

Shadowing is a person-following behavior, commonly observed in dementia (e.g., Alzheimer's disease). It may be caused by neuropsychological impairments associated with posterior brain lesions, as Kudo et al. described it in a patient with posterior cortical atrophy and no frontal signs. These authors have suggested that shadowing may arise from the combination of visuospatial impairments, aphasia, apraxia, and prosopagnosia. However, how these symptoms may contribute to shadowing remains unclear. It is suggested that the combination of visuospatial impairments, body representation disorders, and apraxia, may result in complete loss of spatial representations and hence, shadowing behavior.

Enhanced activity of the left precuneus as a predictor of visuospatial dysfunction correlates with disease activity in rheumatoid arthritis.

OBJECTIVE: To identify the potential diagnostic biomarkers of rheumatoid arthritis (RA) and assess the relation between visuospatial dysfunction and disease activity in RA patients using mental rotation task (MRT)-based functional magnetic resonance imaging (fMRI). METHODS: A total of 27 RA patients (11 in remission, 16 in active) and 27 well-matched controls were enrolled. The visuospatial function of the subjects was measured by MRT. Brain activity data were collected using blood oxygen level dependent fMRI technique under MRT. Disease activity score 28 (DAS28) was used to evaluate the disease severity of RA patients. An analysis of the correlations between abnormal visuospatial-related brain regions, MRT performance, and DAS28 was conducted. RESULTS: RA patients performed worse on MRT than controls. Compared to the control group, RA patients showed enhanced activation in the left precuneus, left superior frontal gyrus and right cingulate gyrus during the rotation task, with left hemisphere dominance. RA patients in active showed enhanced activation in the left precuneus, left middle frontal gyrus and right cingulate gyrus compared to the patients in remission. The left precuneus activation was negatively correlated with MRT accuracy (r = -0.621, p = 0.01) and positively correlated with DAS28 (r = 0.710, p = 0.002), and MRT accuracy was negatively correlated with DAS28 in RA patients (r = -0.702, p = 0.002). CONCLUSION: Enhanced activation of the left precuneus in RA patients affects visuospatial function and is closely related to disease activity. These changes may provide a valuable diagnostic neuroimaging biomarker of RA.

Shadowing Behavior May Be Associated with an Inability to Recognize the External World: A Case Report of Shadowing in a Patient with Posterior Cortical Atrophy.

Although shadowing behavior- when one individual closely follows another- is routinely documented among patients with dementia, its mechanisms have yet to be elucidated. In particular, there have been no detailed descriptions of patients with shadowing behavior. To propose its potential backgrounds, we describe a patient with posterior cortical atrophy who exhibited prominent shadowing behavior. He also experienced severe difficulties recognizing external stimuli, including visuospatial dysfunction, several types of agnosia, difficulties in verbal comprehension, disorientation, and its associated depression. This shadowing behavior may be adaptive relative to his extreme difficulty with recognizing the world around him.

Outcome of visuospatial dysfunction assessment in patients with Parkinson's disease using mobile application software.

Background: Visuospatial dysfunction and cognitive impairment are common in Parkinson's disease (PD), which draw increasing attention in the current literature. But clinicians still lack rapid, effective and unified cognitive battery for visuospatial assessment. Objective: A new approach was studied to explore the feasibility of using mobile application software (APP) to evaluate visuospatial dysfunction in patients with PD and compared with traditional assessment tools. We aimed to verify the threshold score of the APP for early diagnosis. Materials and methods: A total of 41 patients with PD underwent assessments using several test modules including Digit Symbol Test (DST), Visual Organization Test (VOT), Facial Recognition Test (FRT), Vocabulary Memory Test (VMT) of this APP, as well as Clock Drawing Test (CDT), Cube Copying Test (CCT) and the Mini-Mental State Examination (MMSE) for comparison. Among the 41 PD patients, 30 individuals were found to have visuospatial dysfunction based on CDT score < 5 and CCT score of<18 while the remaining 11 patients served as control. Results: There were statistically significant differences in DST, VOT, and FRT scores (all p ≤ 0.001 for group comparisons). DST, VOT, and FRT-1 were significantly correlated with MMSE, CDT and CCT and the correlations were moderate or fairly strong. For visuospatial dysfunction diagnosis, all the areas under curves (AUC) of DST, VOT, and FRT-1 were statistically significant (p < 0.0001, p = 0.0002, and p = 0.0002, respectively). The estimates and 95% confidence intervals of AUC were 0.8303 (0.6868, 0.9739), 0.8045 (0.6423, 0.9668), and 0.7833 (0.6344, 0.9322), respectively. Their cut-off points for visuospatial dysfunction were 26, 17, and 19, respectively. After dichotomization by the cut-off points, DST had high sensitivity of 96.67% while VOT and FRT-1 had high specificity of 81.82 and 90.91%. Conclusion: This study demonstrated that visuospatial disorders was highly prevalent in PD patients, and the APP used in study could be a practical clinical screening tool for visuospatial ability assessment with high sensitivity and specificity.

A single-center, randomized, parallel design study to evaluate the efficacy of donepezil in improving visuospatial abilities in patients with mild cognitive impairment using eye-tracker: the COG-EYE study protocol for a phase II trial.

BACKGROUND: Cholinesterase inhibitors (ChEIs) decrease long-term cognitive decline in patients with Alzheimer's disease (AD); however, there is little evidence that ChEIs affect cognitive test scores in patients with mild cognitive impairment (MCI). Conventional endpoints, such as cognitive tests or clinical rating scores, may lack the sensitivity to subtle treatment effects in participants with MCI. Therefore, there is an immediate need to refocus on direct physiological assessments to detect the effects of ChEIs in patients with MCI due to AD. METHODS: We propose a randomized controlled trial to evaluate the effect of donepezil, a ChEI, on patients with MCI due to AD. We plan to recruit 78 participants (39 in each arm) with MCI who had amyloid positron emission tomography (PET)-positive results for this open-label study. To evaluate subtle differences, we will measure eye-tracking metrics and digital pen data while participants perform the simplified Rey Complex Figure (RCFT) and clock drawing tests. The primary outcome is a change in the ratio of the number of fixations (working space/perceptual space) performed using the simplified RCFT, from baseline to 12 weeks, as assessed using eye-tracking metrics. The secondary outcomes are changes in general cognition, clinical severity, activities of daily living, and visuospatial function assessed using standard rating scores and digital pen data. The analyses of the primary and secondary outcomes will be based on the difference in changes during follow-up between the donepezil and control groups using the t-test or Mann-Whitney U test, as well as adjusting for baseline values. DISCUSSION: This study is designed to determine whether eye-tracking metrics can detect the effect of donepezil on visuospatial dysfunction more sensitively in patients with MCI. It is expected that multimodal data, such as eye-tracking and digital pen data, may provide helpful biomarkers for identifying subtle changes that are difficult to measure using conventional methods. TRIAL REGISTRATION: Clinical Research Information Service, Republic of Korea (CRIS, cris.nih.go.kr) KCT0006236. Registered on June 10, 2021.

Eye-Tracking Metrics for Figure-Copying Processes in Early- vs. Late-Onset Alzheimer's Disease.

Visuospatial dysfunction is a common symptom in patients with Alzheimer's disease (AD). To more focus on copying processes rather than on finally completed figures, we conceptually split the copying processes into three stages: visuoperceptual function, visuoconstructional function, and working memory function. We constructed perceptual and working spaces to investigate the different stages of copying, and then, we compared the number and duration of fixations and saccades and the number of switches across the two spaces. We used eye-tracking glasses to assess eye-tracking metrics in patients with early-onset AD (EOAD), patients with late-onset AD (LOAD), and normal control (NC) participants while they copied the simplified Rey-Osterrieth complex figure test (RCFT). Regarding eye metrics on the perceptual space, the number and duration of fixations were greater in both groups of patients with AD than in the NC participants group (number: EOAD vs. NC: p < 0.001, LOAD vs. NC: p = 0. 003/ duration: EOAD vs. NC: p < 0.001, LOAD vs. NC: p < 0.001). On the working space, the number and duration of fixations were greater in the patients with EOAD than in the patients with LOAD and NC participants (number: EOAD vs. LOAD: p = 0. 007, EOAD vs. NC: p = 0. 001/duration: EOAD vs. LOAD: p = 0. 008, EOAD vs. NC: p = 0. 002). The number of saccades and switching was higher in patients with EOAD than in NC participants (p < 0.001). The eye-tracking metrics from the simplified RCFT correlated with the neuropsychological test scores. Patients with EOAD and LOAD achieved the same level of performance at the simplified and original RCFT scores. However, patients with EOAD than LOAD showed a greater number and duration of fixations on the working space and more frequent switching between the perceptual and working spaces, which may reflect more cognitive efforts to achieve the same level of performance.

Visuospatial dysfunction is associated with posterior distribution of white matter damage in non-demented cerebral amyloid angiopathy.

BACKGROUND AND PURPOSE: Cerebral amyloid angiopathy (CAA) is a well-recognized contributor to cognitive decline in the elderly. The posterior cortical predilection of CAA pathology would cause visuospatial dysfunction, which is still underexplored. We aimed to investigate whether the visuospatial dysfunction in CAA is associated with the posterior distribution of small vessel disease (SVD) imaging markers. METHODS: We recruited 60 non-demented CAA cases from a Chinese prospective cohort and 30 cases with non-CAA SVD as controls. We used the Visual Object and Space Perception (VOSP) battery to evaluate visuospatial abilities, and multivariable regression models to assess their associations with SVD imaging markers. RESULTS: There was visuospatial dysfunction, especially visual object perception impairment, in CAA compared to controls (Z-score of VOSP: -0.11 ± 0.66 vs. 0.22 ± 0.54, p = 0.023). The VOSP score in CAA was independently related to the fronto-occipital gradient of white matter hyperintensity volumes (coefficient = 0.03, 95% confidence interval [CI] = 0.003-0.05, p = 0.030) and mean fractional anisotropy values on diffusion tensor imaging (coefficient = 4.72, 95% CI = 0.97-8.48, p = 0.015), but not the severity of global SVD imaging markers or the gradient of lobar cerebral microbleeds with adjustments for age and global cognition score. CONCLUSIONS: This finding suggests that the damage of posterior white matter rather than global disease severity may be a major contributor to visuospatial dysfunction in CAA.

Stereoscopic Depth Perception and Visuospatial Dysfunction in Alzheimer's Disease.

With visuospatial dysfunction emerging as a potential marker that can detect Alzheimer's disease (AD) even in its earliest stages and with disturbance in stereopsis suspected to be the prime contributor to visuospatial deficits in AD, we assessed stereoscopic abilities of patients with AD and mild cognitive impairment (MCI). Whereas previous research assessing patients' stereoacuity has yielded mixed results, we assessed patients' capacity to process coarse disparities that can convey adequate depth information about objects in the environment. We produced two virtual cubes at two different distances from the observer by manipulating disparity type (absolute vs. relative), disparity direction (crossed vs. uncrossed) and disparity magnitude, then had participants judge the object that appeared closer to them. Two patient groups performed as well as, or even better than elderly controls, suggesting that AD patients' coarse disparity processing capacity is capable of supporting common tasks involving reaching, grasping, driving, and navigation. Results may help researchers narrow down the exact cause(s) of visuospatial deficits in AD and develop and validate measures to assess visuospatial dysfunction in clinical trials and disease diagnosis.

An Informant-Based Simple Questionnaire for Visuospatial Dysfunction Assessment in Dementia.

OBJECTIVES: Visuospatial dysfunction (VSD) is one of the most important symptoms for the diagnosis of dementia with Lewy bodies (DLB). The aim of this study was to validate a novel VSD questionnaire and determine the cutoff score for the screening for VSD in DLB. METHODS: This is a retrospective analysis of data from a project of the History-based Artificial Intelligent Clinical Dementia Diagnostic System (HAICDDS). VSD of non-demented control (NDC), Alzheimer's disease (AD), and DLB participants were analyzed and compared using the visuospatial questionnaire in the HAICDDS (HAI-VSQ), the Draw subscale in the Cognitive Abilities Screening Instrument (CASI-Draw), and the visuospatial subscale in Montreal Cognitive Assessment (MoCA-VS). RESULTS: A total of 440 individuals were studied, including 154 NDC, 229 AD, and 57 DLB participants. Compared to NDC or AD participants, DLB participants showed a higher total score on HAI-VSQ after adjustment for age. Using HAI-VSQ, a cutoff score ≥ 2 was useful for the screening for VSD in DLB with a sensitivity of 0.77 and a specificity of 0.94. Compared with CASI-Draw or MoCA-VS, HAI-VSQ was least influenced by gender, age, and education and had the highest correlation with the sum of boxes of the Clinical Dementia Rating scale. After adjustment for age, education, gender, and global cognitive function, HAI-VSQ significantly discriminated DLB from AD and NDC whereas MoCA-VS or CASI-Draw did not. CONCLUSION: Our study showed that the newly designed simple questionnaire was a practical screening tool for VSD in DLB that can be applied in clinical practice as well as on a registration platform.

Tau PET Distributional Pattern in AD Patients with Visuospatial Dysfunction.

BACKGROUND: Visuospatial dysfunction is one predominant symptom in many atypical Alzheimer's disease (AD) patients, however, until now its neural correlates still remain unclear. For the accumulation of intracellular hyperphosphorylated tau proteins is a major pathogenic factor in neurodegeneration of AD, the distributional pattern of tau could highlight the affected brain regions associated with specific cognitive deficits. OBJECTIVE: We investigated the brain regions particularly affected by tau accumulation in patients with visuospatial dysfunction to explore its neural correlates. METHODS: Using 18F-AV-1451 tau positron emission tomography (PET), voxel-wise two-sample t-tests were performed between AD patients with obvious visuospatial dysfunction (VS-AD) and cognitively normal subjects, AD patients with little-to-no visuospatial dysfunction (non VS-AD) and cognitively normal subjects, respectively. RESULTS: Results showed increased tau accumulations mainly located in occipitoparietal cortex, posterior cingulate cortex, precuneus, inferior and medial temporal cortex in VS-AD patients, while increased tau accumulations mainly occurred in the inferior and medial temporal cortex in non VS-AD patients. CONCLUSION: These findings suggested that occipitoparietal cortex, posterior cingulate cortex and precuneus, which were particularly affected by increased tau accumulation in VS-AD patients, may associate with visuospatial dysfunction of AD.

Executive and Visuospatial Dysfunction in Patients With Primary Restless Legs Syndrome/Willis-Ekbom Disease: Study of a Chinese Population.

STUDY OBJECTIVES: The aim of the study was to investigate the cognitive function of patients with primary restless legs syndrome/Willis-Ekbom disease (RLS/ WED) in a Chinese population. METHODS: A total of 40 patients with RLS/WED who were drug naïve and 40 controls, matched by age, sex, and educational level, were evaluated by cognitive function assessments, including the Chinese version of the Mini-Mental State Examination (MMSE-C), clock drawing test (CDT), Auditory Verbal Learning Test (AVLT), Rey-Osterrieth Complex Figure Test (CFT), and Stroop Color Word Test (SCWT). RESULTS: Patients with RLS/WED showed worse performance on the SCWT (Stroop Card C time: 102.36 ± 17.12 versus 87.08 ± 7.73 seconds, P = .033; Interference Index: 3.39 ± 0.38 versus 2.90 ± 0.15, P < .0001), CFT (24.05 ± 9.28 versus 33.74 ± 1.59, P = .008), and CDT than controls (16-score method: 10.13 ± 3.94 versus 13.98 ± 1.79, P = .0002) after adjusting for Hamilton Anxiety Scale score, Hamilton Depression Scale score, Epworth Sleepiness Scale score, and Pittsburgh Sleep Quality Index total score to eliminate the confounders of concomitant sleep disturbances, anxiety, and depression. CONCLUSIONS: Our study suggested that cognitive functions involving executive and visuospatial domains might be disturbed in Chinese patients with primary RLS/WED.

The Heidenhain variant of Creutzfeldt-Jakob disease and concomitant tau pathology: A case report.

The Heidenhain form of Creutzfeldt-Jakob disease (CJD) is a rare CJD variant with predominantly visual symptoms in the early stages. Clinical manifestations of metamorphopsia, hemianopia and Balint's syndrome correlate with the involvement of the posterior cortical regions. A 71-year old healthy and very active man was admitted because of impaired visual acuity, hemianopia, and gait disturbance progressing over one week. MRI found typical cortical hyperintensities in the occipital regions while rhythm slowing and sharp waves were seen in the occipital regions on EEG. Protein 14-3-3 was detected in the cerebrospinal fluid. Postmortem neuropathology revealed typical histopathological changes consistent with CJD. Moreover, we found deposits of phosphorylated tau protein in the limbic regions that met the criteria for primary age-related tauopathy (PART); representing an additional and interesting finding in our case.

Constructional apraxia in frontotemporal dementia associated with the C9orf72 mutation: broadening the clinical and neuropsychological phenotype.

In our study we analysed clinical and neuropsychological data in a cohort of 57 Sardinian patients with FTD (55 apparently unrelated and two belonging to the same family), who underwent genetic screening for the C9orf72 mutation. Eight out of 56 patients were found positive for the C9orf72 mutation representing 14% of the entire cohort and 31.6% of the familial cases (6/19). C9orf72 mutated patients differed from the other FTD cases of the cohort for a younger age of onset, higher frequency of familial history for FTD and higher prevalence of delusional psychotic symptoms and hallucinations. In the neuropsychological assessment, C9orf72 mutated patients differed from non-mutated for the high frequency of visuospatial dysfunction regarding constructional apraxia (p = 0.02). In conclusion, our study confirms that Sardinian FTD patients have peculiar genetic characteristics and that C9orf72 mutated patients have a distinctive clinical and neuropsychological profile that could help differentiate them from other FTD patients. In our cohort we found that constructional apraxia, rarely reported in FTD, can properly discriminate between C9orf72 mutated and non-mutated patients and contribute to broaden the neuropsychological profile in frontotemporal dementia associated with this mutation.

Freezing of gait subtypes have different cognitive correlates in Parkinson's disease.

BACKGROUND: Freezing of gait (FOG) is a major concern for Parkinson's disease (PD) patients because it is a leading cause of falls and is associated with poor quality of life. The pathophysiology is unknown but it is hypothesized that it relates to cognitive abnormalities; particularly executive and visuospatial dysfunction. However, prior results have been discrepant. Pharmacologic subtypes of FOG include those that are responsive and unresponsive to levodopa. OBJECTIVE: To determine whether executive and visuospatial dysfunction are associated specifically with the levodopa unresponsive subtype of FOG. METHODS: 135 PD subjects completed a single assessment included FOG questionnaire, UPDRS motor scale, comprehensive cognitive battery and measure of hallucinations. Analyses compared unresponsive (n = 16), responsive (n = 20) and no FOG (n = 99) subtypes. RESULTS: The unresponsive subtype had a significantly older age of onset of PD than the responsive group (p = .03) and had worse motor scores (p = .003) than the no FOG group. Longer disease duration was associated with the responsive group compared to the no FOG group (p = .002). The unresponsive FOG group had significantly poorer visuospatial ability (p = .001) and executive functioning (p = .02) than both the no and responsive FOG subgroups. These latter groups were not significantly different. The responsive FOG group was associated with the presence of hallucinations. CONCLUSION: Aside from pharmacological differences, unresponsive FOG is associated with executive and visuospatial dysfunction implicating frontostriatal pathways while responsive FOG is associated with hallucinations suggesting involvement of posterior cortical regions. Further study and treatment of FOG should include appropriate subtype classification.

Cognitive dysfunction associated with falls in progressive supranuclear palsy.

BACKGROUND: Attentional and executive dysfunctions are associated with falls in community-dwelling elderly individuals and patients with PD. Frontal cognitive dysfunction and falls are frequent symptoms of PSP. We studied to identify the cognitive domains associated with recurrent falls in patients with PSP. METHODS: We performed a battery of neuropsychological tests in 59 individuals with probable PSP. We categorized patients into infrequent fall (≤one fall during the last 12 months, n=29) or recurrent fall (≥two falls during the last 12 months, n=30) groups. RESULTS: UPDRS subscores for axial deficits were significantly higher in the recurrent fall group than the infrequent fall group, but there were no significant differences in UPDRS total motor scores or subscores for bradykinesia, rigidity, and tremor. There was no difference between groups in MMSE scores. ANCOVA with adjustment for confounding factors showed that, recurrent falls were associated with abnormalities in alternating hand movement, alternating square and triangle, RCFT copying task, and ideomotor apraxia. Group difference of abnormalities in Stroop test was marginal (p=0.054). However, there were no group differences in the frequency of abnormalities in forward or backward digit span, motor impersistence, fist-edge-palm, contrast programming, go-no-go, Luria loop drawing, or Controlled Oral Word Association Tests. Recurrent falls were not associated with memory or language dysfunction. CONCLUSIONS: Recurrent falls in patients with PSP were associated mainly with executive and visuospatial dysfunctions, including (1) impaired coordinated alternating uni- and bimanual motor programming and execution, (2) deficit of attention and decision making in the presence of interference, (3) visuospatial misperception and (4) ideomotor apraxia.

Progressive posterior cortical dysfunction / Disfunção cortical posterior progressiva

Progressive posterior cortical dysfunction (PPCD) is an insidious syndrome characterized by prominent disorders of higher visual processing. It affects both dorsal (occipito-parietal) and ventral (occipito-temporal) pathways, disturbing visuospatial processing and visual recognition, respectively. We report a case of a 67-year-old woman presenting with progressive impairment of visual functions. Neurologic examination showed agraphia, alexia, hemispatial neglect (left side visual extinction), complete Balint?s syndrome and visual agnosia. Magnetic resonance imaging showed circumscribed atrophy involving the bilateral parieto-occipital regions, slightly more predominant to the right . Our aim was to describe a case of this syndrome, to present a video showing the main abnormalities, and to discuss this unusual presentation of dementia. We believe this article can contribute by improving the recognition of PPCD.

Disfunção cortical posterior progressiva (DCPP) é um síndrome insidiosa caracterizada por distúrbios do processamento visual superior. Ela afeta tanto a via dorsal (occipito-parietal) como a ventral (occipito-temporal), alterando o processamento visuoespacial e reconhecimento visual, respectivamente. Nós relatamos o caso de uma mulher de 67 anos com dificuldade progressiva nas funções visuais. O exame neurológico mostrou agraphia, alexia, negligência especial (extinção visual à esquerda), síndrome de Balint complete e agnosia visual. A ressonância magnética mostrou atrofia nas regiões parieto-occipitais, mais evidente à direita. Nosso objetivo foi descrever um caso desta síndrome, apresentar um vídeo mostrando as principais anormalidades e discutir esta apresentação incomum de demência. Nós esperamos que o artigo possa facilitar o reconhecimento da DCPP.

Progressive posterior cortical dysfunction.

Progressive posterior cortical dysfunction (PPCD) is an insidious syndrome characterized by prominent disorders of higher visual processing. It affects both dorsal (occipito-parietal) and ventral (occipito-temporal) pathways, disturbing visuospatial processing and visual recognition, respectively. We report a case of a 67-year-old woman presenting with progressive impairment of visual functions. Neurologic examination showed agraphia, alexia, hemispatial neglect (left side visual extinction), complete Balint's syndrome and visual agnosia. Magnetic resonance imaging showed circumscribed atrophy involving the bilateral parieto-occipital regions, slightly more predominant to the right. Our aim was to describe a case of this syndrome, to present a video showing the main abnormalities, and to discuss this unusual presentation of dementia. We believe this article can contribute by improving the recognition of PPCD.

Disfunção cortical posterior progressiva (DCPP) é um síndrome insidiosa caracterizada por distúrbios do processamento visual superior. Ela afeta tanto a via dorsal (occipito-parietal) como a ventral (occipito-temporal), alterando o processamento visuoespacial e reconhecimento visual, respectivamente. Nós relatamos o caso de uma mulher de 67 anos com dificuldade progressiva nas funções visuais. O exame neurológico mostrou agraphia, alexia, negligência especial (extinção visual à esquerda), síndrome de Balint complete e agnosia visual. A ressonância magnética mostrou atrofia nas regiões parieto-occipitais, mais evidente à direita. Nosso objetivo foi descrever um caso desta síndrome, apresentar um vídeo mostrando as principais anormalidades e discutir esta apresentação incomum de demência. Nós esperamos que o artigo possa facilitar o reconhecimento da DCPP.