Laura Veronelli

Introduction: Recent studies in right-brain-damaged patients with an acquired reading disorder have shown that omission and substitution errors in reading single words and pseudowords may result from two different mechanisms: the association of spatial neglect with altered eye movements (neglect dyslexia), which produces left-sided omissions, or an enhancement of a crowding phenomenon (crowding dyslexia), responsible for less lateralized substitutions. This study aims to provide normative data for the Spacing Words and Pseudowords (SWAP) reading test for the Italian population, a novel tool sensitive to identify specific visuo-perceptual and attentional deficits in patients with acquired peripheral dyslexia based on the modulatory effect of letter spacing. Methods: The test was administered to 199 neurologically unimpaired Italian participants (86 males), with an average age of 57.3 years (range 20–90) and an average education of 14.1 years (range 5–28). An innovative scoring method based on the type and position of errors (letter-based) was proposed, and the effect of spacing condition on specific types of errors was investigated. Results: Regression-based norms are provided for both word-based and letter-based errors. A significant effect of spacing on accuracy, with an increased number of errors in the spaced compared to the unspaced condition, was observed for substitutions and additions, but not for omissions. Furthermore, examples to illustrate the clinical application of the test in right-brain-damaged patients with acquired dyslexia are described. Discussion: The SWAP reading test, provided with proper norms, may serve as a clinical tool to investigate visual-perceptual and attentional mechanisms involved in reading and possibly affected by brain damage, disentangling neglect dyslexia from crowding dyslexia.

Introduction: Glutaric Aciduria type I (GA1) is a rare autosomal recessive organic aciduria, with typical early-onset presentation, characterized by severe movement disorders with damage to the basal ganglia following an acute encephalopathic crisis. Late-onset (LO), milder forms have rarely been described. In LO patients, severe brain damage is frequently reported, including frontotemporal hypoplasia, brain atrophy, subependymal nodules and leukodystrophy. Cognitive impairment is sometimes described, often without formal psychometric assessment. Objectives: This scoping review aims to synthesize the neuroradiological and neuropsychological features of all LO GA1 patients reported in the literature to date, divided in undiagnosed LO cases detected through selective screening and LO cases with onset of symptoms after 6 years of age. Methods: The following databases were used: PubMed, Embase and Medline. The search strategy abides by the PRISMA-ScR guidelines. Results: Out of the 53 LO patients reviewed, extensive quantitative neuropsychological testing was reported in seven cases, while no brain morphometric analysis was performed. Case report: CASE REPORT. A novel case of a GA1 34-year-old Chinese woman identified through the neonatal screening of her healthy baby is described. Brain morphometric analysis showed diffused reduced volumes and cortical thinning, involving fronto-temporal areas and, to a lesser extent, the parieto-occipital regions. The neuropsychological assessment highlighted mild difficulties in verbal executive functions (inferential thinking) and phonological short-term memory. Conclusion: The present review and case report suggest that integrating neuroanatomical and neuropsychological investigations into clinical practice may allow a more refined characterization of GA1 patients, contributing to unveil the complex ethio-pathogenic mechanisms underlying the disease and monitor patients over time.

Disorders in global processing abilities may be evident when posterior cortical regions are damaged due to a focal brain lesion or neurodegenerative diseases, such as posterior cortical atrophy (PCA). While in severe cases global processing deficits are evident as simultanagnosia, subtle impairments may be present early, as in patients with multi-domain mild cognitive impairment (MCI). The aim of the present study is to provide norms for the Computerized Open-Source Navon Test (COSNaT), which has already been validated in clinical populations. After a baseline that requires identifying large and small standard letters, the test measures the ability to identify the global and local levels of incongruent Navon’s hierarchical letters. A total of 200 neurologically unimpaired participants (113 F, 56.5%) with a mean age of 57.2 years (range 20–90) and a mean education of 14.1 years (range 5–28) took part in the study. The influence of demographic variables (age, education, sex) on participants’ performance was evaluated using measures of errors and response times (global, local, and delta global/local). Raw scores, regression-based adjustments for age and education levels, and equivalent scores were provided for each index. The present study provides norms in the Italian population for the COSNaT, which has been shown to be sensitive in detecting global processing impairments and simultanagnosia in different clinical populations (PCA, amnestic MCI). The computerized test may contribute to a more accurate clinical characterization of the neuropsychological profile of patients with different etiologies, as well as in prodromal stages of neurodegenerative diseases.

Background: Visuo-perceptual and visuo-attentional disorders, such as global processing deficit and simultanagnosia, are not routinely investigated in prodromal forms of typical Alzheimer’s disease, as amnestic mild cognitive impairment (MCI). Objective: This study evaluated global processing abilities through Navon’s classical paradigm in individuals with amnestic MCI and investigated the related visuo-perceptual and attentional components involved in simultanagnosia. Methods: Sixteen consecutive patients with amnestic MCI (6 single-domain, 10 multiple-domain) and 16 matched controls were requested to identify global and local elements of hierarchical Navon letters, and to name large and small solid letters. Results: While correctly identifying solid letters, patients with multiple-domain amnestic MCI were less accurate in processing the global level of hierarchical stimuli compared to controls. Single-case analyses suggested that global processing may also be impaired in single-domain amnestic MCI. In addition, patients with pathological performance in the Navon task showed perceptual and/or visual focal attention deficits. Conclusions: Early dysfunction of holistic processing can be detected in amnestic MCI. Visuo-perceptual and/or visual focal attention mechanisms, which have been shown to be damaged in Posterior Cortical Atrophy patients with simultanagnosia, may be impaired in individuals with amnestic MCI. Investigation and identification of global processing deficits in MCI could contribute to early diagnosis and longitudinal monitoring of the disease.

Optic Aphasia (OA) and Associative Visual Agnosia (AVA) are neuropsychological disorders characterized by impaired naming on visual presentation. From a cognitive point of view, while stimulus identification is largely unimpaired in OA (where access to semantic knowledge is still possible), in AVA it is not. OA has been linked with right hemianopia and disconnection of the occipital right-hemisphere (RH) visual processing from the left hemisphere (LH) language areas.In this paper, we describe the case of AA, an 81-year-old housewife suffering from a deficit in naming visually presented stimuli after left occipital lesion and damage to the interhemispheric splenial pathway. AA has been tested through a set of tasks assessing different levels of visual object processing. We discuss behavioral performance as well as the pattern of lesion and disconnection in relation to a neurocognitive model adapted from Luzzatti and colleagues (1998). Despite the complexity of the neuropsychological picture, behavioral data suggest that semantic access from visual input is possible, while a lesion-based structural disconnectome investigation demonstrated the splenial involvement.Altogether, neuropsychological and neuroanatomical findings support the assumption of visuo-verbal callosal disconnection compatible with a diagnosis of OA.