FunctionaL Assessment Scale of Hemianopia (FLASH): A New Multidisciplinary Tool to Assess Hemianopia in Patients with Severe Acquired Brain Injury

BACKGROUND

Severe acquired brain injury (sABI) encompasses a range of neurological impairments. Visual dysfunction, particularly homonymous visual field defects (HVFDs) and homonymous hemianopia (HH), commonly afflicts sABI survivors, affecting their cognitive and motor rehabilitation. This study presents the FunctionaL Assessment Scale of Hemianopia (FLASH), developed to analyze the most common postural behaviors exhibited by sABI patients with hemianopia during activities of daily living. A comparison to traditional static automated perimetry for diagnosing visual field deficits (VFDs) to determine the sensitivity and specificity of the FLASH was used. Additionally, this study also aimed to assess its reliability.

METHODS

Fifty-six patients (25 F, 31 M, mean age 60.59 ± 14.53) with strokes in the sub-acute phase (<6 months from the onset) were assessed with both FLASH and a Humphrey Field Analyzer.

RESULTS

After removing two items found to be less reliable than others, FLASH showed high sensitivity (81%) and specificity (77%) when compared to static automated perimetry. Inter-rater reliability was also high, with an intra-class correlation coefficient of 0.954, as well as the internal consistency computed by Cronbach's alpha, equal to 0.874.

CONCLUSION

FLASH could offer a valuable and cost-effective screening tool for VFD in sABI patients during neurorehabilitation, with potential implications for healthcare cost reduction.

New Insights into Dyskerin-CypA Interaction: Implications for X-Linked Dyskeratosis Congenita and Beyond

The highly conserved family of cyclophilins comprises multifunctional chaperones that interact with proteins and RNAs, facilitating the dynamic assembly of multimolecular complexes involved in various cellular processes. Cyclophilin A (CypA), the predominant member of this family, exhibits peptidyl-prolyl cis-trans isomerase activity. This enzymatic function aids with the folding and activation of protein structures and often serves as a molecular regulatory switch for large multimolecular complexes, ensuring appropriate inter- and intra-molecular interactions. Here, we investigated the involvement of CypA in the nucleus, where it plays a crucial role in supporting the assembly and trafficking of heterogeneous ribonucleoproteins (RNPs). We reveal that CypA is enriched in the nucleolus, where it colocalizes with the pseudouridine synthase dyskerin, the catalytic component of the multifunctional H/ACA RNPs involved in the modification of cellular RNAs and telomere stability. We show that dyskerin, whose mutations cause the X-linked dyskeratosis (X-DC) and the Hoyeraal-Hreidarsson congenital ribosomopathies, can directly interact with CypA. These findings, together with the remark that substitution of four dyskerin prolines are known to cause X-DC pathogenic mutations, lead us to indicate this protein as a CypA client. The data presented here suggest that this chaperone can modulate dyskerin activity influencing all its partecipated RNPs.

Sensitivity and Specificity of the Brentano Illusion Test in the Detection of Visual Hemi-Field Deficits in Patients with Unilateral Spatial Neglect

Stroke survivors with right-brain damage (RBD) often present with attentional deficits such as left unilateral spatial neglect. Some patients also present with contralesional visual hemi-field deficits. A late detection of visual hemi-field deficits (VHFD) contributes to hampering neurorehabilitation and functional outcome of patients with neglect. The Brentano Illusion Test (BRIT) may be used for an early detection of VHFD during the neuropsychological assessment. In the present study, we determined the sensitivity and specificity of the BRIT for screening VHFD in patients with neglect. Sixty-four consecutive RBD patients were examined. Forty-five presented with neglect. Of these, 23 presented with VHFD (hemianopia or quadrantanopia) as detected by the Humphrey automated static visual field testing (reference standard). Consecutive patients also included 19 participants without neglect, who did not have any VHFD. The sensitivity and specificity of the BRIT for neglect patients were 78.3% (95% CI: 61.4-95.1) and 90.9 (95% CI: 78.9-100.0), respectively. Positive predictive value (PPV) was 89.6% (95% CI: 76.4-100.0); negative predictive value (NPV) 80.7% (95% CI: 65.2-96.2). No false positives in the group without neglect were identified. We conclude that the BRIT is an effective tool for clinical neuropsychologists to screen for possible VHFD in neglect patients during the neuropsychological assessment, allowing the refinement of the clinical picture in the neuropsychological report. An early detection of VHFD also allows referring the patient to standard diagnostics for a formal visual field examination, right from the first neuropsychological assessment.

Manipulating color and other visual information influences picture naming at different levels of processing: evidence from Alzheimer subjects and normal controls

There is now a large body of evidence suggesting that color and photographic detail exert an effect on recognition of visually presented familiar objects. However, an unresolved issue is whether these factors act at the visual, the semantic or lexical level of the recognition process. In the present study, we investigated this issue by having Alzheimer's patients and normal controls name figures in four presentation displays (PDs): black and white and colored line drawings, and black and white and color photographs. We also collected image agreement (IA) values (a measure of the extent to which the presented figure matches the stored structural description of the depicted object) for the same stimuli and compared the effects of PD on IA and naming accuracy. Our results suggest that color acts on naming by assisting semantic processing of the stimuli to be recognized; by contrast, photographic detail seems to benefit visual processing by increasing IA.

Color discrimination performance in patients with Alzheimer's disease

BACKGROUND/AIMS

Visual deficits are frequent in Alzheimer's disease (AD), yet little is known about the nature of these disturbances. The aim of the present study was to investigate color discrimination in patients with AD to determine whether impairment of this visual function is a cognitive or perceptive/sensory disturbance.

METHODS

A cross-sectional clinical study was conducted in a specialized dementia unit on 20 patients with mild/moderate AD and 21 age-matched normal controls. Color discrimination was measured by the Farnsworth-Munsell 100 hue test. Cognitive functioning was measured with the Mini-Mental State Examination (MMSE) and a comprehensive battery of neuropsychological tests. The scores obtained on the color discrimination test were compared between AD patients and controls adjusting for global and domain-specific cognitive performance.

RESULTS

Color discrimination performance was inversely related to MMSE score. AD patients had a higher number of errors in color discrimination than controls (mean +/- SD total error score: 442.4 +/- 84.5 vs. 304.1 +/- 45.9). This trend persisted even after adjustment for MMSE score and cognitive performance on specific cognitive domains.

CONCLUSIONS

A specific reduction of color discrimination capacity is present in AD patients. This deficit does not solely depend upon cognitive impairment, and involvement of the primary visual cortex and/or retinal ganglionar cells may be contributory.

Mycotoxin T-2 and aflatoxin B1 as immunosuppressors in mice chronically infected with Toxoplasma gondii

The aim of this study was to determine whether repeated ingestion of mycotoxin T-2 (T2) or aflatoxin B1 (AFL) at low doses could contribute to the activation of toxoplasmosis in experimentally infected mice. Mice were divided into two groups: Control (C) and Infected (I). The cyst-forming Beverley strain of Toxoplasma gondii was used to produce the infection one month before treatment with mycotoxins. Mycotoxins were given intragastrically for a 50-day period. The average weight gain was reduced in the groups treated with mycotoxins. Mice developed specific IgG to T. gondii. Histopathological studies showed severe encephalitis in all groups infected. The number of unruptured and ruptured cysts was established and the severity of the lesions was evaluated, the groups treated with mycotoxins being the most severely affected. Immunohistochemical studies of the brain showed free antigen in tissues surrounding ruptured cysts. It is suggested that low and repeated doses of mycotoxins, necessary to produce a subclinical intoxication, precipitate Toxoplasma cyst rupture and consequently the activation of chronic toxoplasmosis.