Impaired language in Alzheimer's disease: A comparison between English and Persian implicates content-word frequency rather than the noun-verb distinction.

This study challenges the conventional psycholinguistic view that the distinction between nouns and verbs is pivotal in understanding language impairments in neurological disorders. Traditional views link frontal brain region damage with verb processing deficits and posterior temporoparietal damage with noun difficulties. However, this perspective is contested by findings from patients with Alzheimer's disease (pwAD), who show impairments in both word classes despite their typical temporoparietal atrophy. Notably, pwAD tend to use semantically lighter verbs in their speech than healthy individuals. By examining English-speaking pwAD and comparing them with Persian-speaking pwAD, this research aims to demonstrate that language impairments in Alzheimer's disease (AD) stem from the distributional properties of words within a language rather than distinct neural processing networks for nouns and verbs. We propose that the primary deficit in AD language production is an overreliance on high-frequency words. English has a set of particularly high-frequency verbs that surpass most nouns in usage frequency. Since pwAD tend to use high-frequency words, the byproduct of this word distribution in the English language would be an over-usage of high-frequency verbs. In contrast, Persian features complex verbs with an overall distribution lacking extremely high-frequency verbs like those found in English. As a result, we hypothesize that Persian-speaking pwAD would not have a bias toward the overuse of high-frequency verbs. We analyzed language samples from 95 English-speaking pwAD and 91 healthy controls, along with 27 Persian-speaking pwAD and 27 healthy controls. Employing uniform automated natural language processing methods, we measured the usage rates of nouns, verbs, and word frequencies across both cohorts. Our findings showed that English-speaking pwAD use higher-frequency verbs than healthy individuals, a pattern not mirrored by Persian-speaking pwAD. Crucially, we found a significant interaction between the frequencies of verbs used by English and Persian speakers with and without AD. Moreover, regression models that treated noun and verb frequencies as separate predictors did not outperform models that considered overall word frequency alone in classifying AD. In conclusion, this study suggests that language abnormalities among English-speaking pwAD reflect the unique distributional properties of words in English rather than a universal noun-verb class distinction. Beyond offering a new understanding of language abnormalities in AD, the study highlights the critical need for further investigation across diverse languages to deepen our insight into the mechanisms of language impairments in neurological disorders.

Language Abnormalities in Alzheimer's Disease Arise from Reduced Informativeness: A Cross-Linguistic Study in English and Persian.

INTRODUCTION: This research investigates the psycholinguistic origins of language impairments in Alzheimer's Disease (AD), questioning if these impairments result from language-specific structural disruptions or from a universal deficit in generating meaningful content. METHODS: Cross-linguistic analysis was conducted on language samples from 184 English and 52 Persian speakers, comprising both AD patients and healthy controls, to extract various language features. Furthermore, we introduced a machine learning-based metric, Language Informativeness Index (LII), to quantify informativeness. RESULTS: Indicators of AD in English were found to be highly predictive of AD in Persian, with a 92.3% classification accuracy. Additionally, we found robust correlations between the typical linguistic abnormalities of AD and language emptiness (low LII) across both languages. DISCUSSION: Findings suggest AD linguistics impairments are attributed to a core universal difficulty in generating informative messages. Our approach underscores the importance of incorporating biocultural diversity into research, fostering the development of inclusive diagnostic tools.

Novel adjustable monolayer carbon nitride membranes for high-performance saline water desalination.

In this study, via molecular dynamic simulations, we showed that the latest described graphene-like carbon nitride membranes, such as g-C4N3, g-C6N6, and g-C3N4 single-layers, can be used as high-performance membranes for water desalination. In addition to having inherent nanopores and extraordinary mechanical properties, the carbon nitride membranes have high water permeability and strong ion rejection (IR) capability. The important point about carbon nitride membranes is that the open or closed state of the pores can be changed by applying tensile stress and creating a positive strain on the membrane. The effect of the imposed pressure, the tensile strain, the ion concentration, and the effective pore size of the membranes are reported. It is demonstrated that, with the applied tensile strain of 12%, the g-C6N6 membrane is the best purification membrane, with a water permeability of 54.16 l cm-2 d-1 MPa-1 and the IR of 100%. Its water permeability is one order of magnitude greater than other one-atom-thick membranes.

Metallic artifact in MRI after removal of orthopedic implants.

OBJECTIVE: The aim of the present study was to evaluate the metallic artifacts in MRI of the orthopedic patients after removal of metallic implants. SUBJECTS AND METHODS: From March to August 2009, 40 orthopedic patients operated for removal of orthopedic metallic implants were studied by post-operative MRI from the site of removal of implants. A grading scale of 0-3 was assigned for artifact in MR images whereby 0 was considered no artifact; and I-III were considered mild, moderate, and severe metallic artifacts, respectively. These grading records were correlated with other variables including the type, size, number, and composition of metallic devices; and the site and duration of orthopedic devices stay in the body. RESULTS: Metallic susceptibly artifacts were detected in MRI of 18 of 40 cases (45%). Screws and pins in removed hardware were the most important factors for causing artifacts in MRI. The artifacts were found more frequently in the patients who had more screws and pins in the removed implants. Gender, age, site of implantation of the device, length of the hardware, composition of the metallic implants (stainless steel versus titanium), and duration of implantation of the hardware exerted no effect in producing metallic artifacts after removal of implants. Short TE sequences of MRI (such as T1 weighted) showed fewer artifacts. CONCLUSION: Susceptibility of metallic artifacts is a frequent phenomenon in MRI of patients upon removal of metallic orthopedic implants.

Pseudolisthesis secondary to small L5.

RATIONALE AND OBJECTIVE: Small AP diameter of L5 can mimic spondylolisthesis in lumbosacral MRI. The aim of the present study was to evaluate the prevalence of small L5 mimicking spondylolisthesis in lumbosacral MRI of the patients referred to an imaging center by any symptoms. Association between small anteroposterior diameter of L5 and presence and absence of unilateral or bilateral spondylolysis at L5 were also evaluated. MATERIALS AND METHODS: 2000 lumbosacral MRI of the patients referred to an imaging center for any reasons were evaluated. The posterior step of L5 was measured and the cases with posterior step of more than 2 mm were selected. These cases were evaluated for presence or absence of spondylolysis. RESULTS: Small anteroposterior diameters of L5 were detected in 38 cases (2%), mimicking the spondylolisthesis in lumbosacral MRI. The prevalence of small L5 in lumbosacral MRI of the patients referred by any symptoms was about 2%. In these selected cases, 6 (15.8%) show unilateral spondylolysis and 5 (13.1%) show bilateral spondylolysis. CONCLUSION: Pseudospondylolisthesis secondary to small AP diameter of L5 has prevalence of about 2% in lumbosacral MRI of cases referred for any reasons and can be overlooked in reporting of LS MRI. There was an association between small anteroposterior diameter of L5 and presence of spondylolysis at L5.