Repeated cognitive assessments are frequently necessary to evaluate how interventions affect the behavior of participants in cognitive psychology, neuropsychology, and psycholinguistic experiments. Repeated cognitive assessments can lead to familiarity with test materials, which could affect test performance. To prevent potentially misleading outcomes, stemming from increased familiarity rather than the intervention itself, it’s important to employ alternate forms of tests using words as stimuli. During the development of these alternate forms, each stimulus is carefully substituted with another stimulus that has identical psycholinguistic properties. The absence of normative data for words’ psycholinguistic properties poses significant obstacles in research. In this study, we introduce the Greek- Cypriot Word Pool (G-CWP), a dataset providing normative values for imageability and concreteness for approximately 2,950 Greek words. Both variables are well-known for their influence on the speed and precision with which words can be recalled, recognized, named, and classified. We gathered imageability data from 366 Greek-Cypriots and concreteness data from 312 Greek-Cypriots. For the majority of the words, no significant gender differences were found. However, we did observe a significant, albeit negligible, effect of education on both variables. Our data demonstrate good interval reliability, consistency, and validity, verifying the reliability and validity of the obtained norms. Therefore, the G-CWP offers valuable metrics for researchers working with Greek-Cypriot participants, enabling them to effectively control and manipulate words that are used as stimuli in experiments.

Transcranial magnetic stimulation (TMS) on early visual cortex (i.e., areas V1/V2, MT+/V5) can evoke visual percepts, known as phosphenes. Hence, TMS studies often rely on the induction of phosphenes as an early visual cortex localization method or as a brain excitability heuristic. Subsequently, researchers have depended on the induction of phosphenes for both applied and basic research. For example, studies have used phosphene induction to understand brain excitability differences in migraine patients [[1]Brigo F. Storti M. Nardone R. Fiaschi A. Bongiovanni L.G. Tezzon F. Manganotti P. Transcranial magnetic stimulation of visual cortex in migraine patients: a systematic review with meta-analysis.J Headache Pain. 2012; 13: 339-349https://doi.org/10.1007/s10194-012-0445-6Crossref PubMed Scopus (57) Google Scholar], to test new technologies, such as transcranial focused ultrasound [[2]Schimek N. Burke-Conte Z. Abernethy J. Schimek M. Burke-Conte C. Bobola M. Mourad P.D. Repeated application of transcranial diagnostic ultrasound towards the visual cortex induced illusory visual percepts in healthy participants.Front Hum Neurosci. 2020; 14: 66https://doi.org/10.3389/fnhum.2020.00066Crossref PubMed Scopus (8) Google Scholar], and to investigate the neural substrates of visual perception [[3]de Graaf T.A. Koivisto M. Jacobs C. Sack A.T. The chronometry of visual perception: review of occipital TMS masking studies.Neurosci Biobehav Rev. 2014; 45: 295-304https://doi.org/10.1016/j.neubiorev.2014.06.017Crossref PubMed Scopus (56) Google Scholar] and visual working memory [[4]Phylactou P. Traikapi A. Papadatou-Pastou M. Konstantinou N. Sensory recruitment in visual short-term memory: a systematic review and meta-analysis of sensory visual cortex interference using transcranial magnetic stimulation.Psychonomic Bull Rev. 2022; : 1-31https://doi.org/10.3758/s13423-022-02107-yCrossref Scopus (3) Google Scholar]. However, it is not always possible to evoke phosphenes in human subjects using early visual cortex TMS. This is reflected by the exclusion of participants in early visual cortex TMS studies, due to the failure of reporting the experience of any visual percepts. This failure has been attributed to various factors, such as the subjective nature of phosphene reporting, the lack of perceptual practice of participants, and differences in stimulation parameters [[5]Kammer T. Puls K. Erb M. Grodd W. Transcranial magnetic stimulation in the visual system. II. Characterization of induced phosphenes and scotomas.Exp Brain Res. 2005; 160: 129-140https://doi.org/10.1007/s00221-004-1992-0Crossref PubMed Scopus (121) Google Scholar]. Because of these factors leading to the exclusion of participants, TMS studies can often turn out to be underpowered and/or deviate from the initially planned sample size, thus limiting the conclusions reached by those studies. Previous empirical studies, have provided numerous phosphene prevalence estimations, based on their experimental sample, with estimates of successfully inducing phosphenes ranging anywhere between 25% [[6]Aurora S.K. Cao Y. Bowyer S.M. Welch K.M.A. The occipital cortex is hyperexcitable in migraine: experimental evidence.Headache J Head Face Pain. 1999; 39: 469-476https://doi.org/10.1046/j.1526-4610.1999.3907469.xCrossref PubMed Scopus (168) Google Scholar] and 100% [[7]van Lamsweerde A.E. Johnson J.S. Assessing the effect of early visual cortex transcranial magnetic stimulation on working memory consolidation.J Cognit Neurosci. 2017; 29: 1226-1238https://doi.org/10.1162/jocn_a_01113Crossref PubMed Scopus (18) Google Scholar]. Previous work has often reported that a common phosphene prevalence estimate is approximately 60% [[8]Romei V. Brodbeck V. Michel C. Amedi A. Pascual-Leone A. Thut G. Spontaneous fluctuations in posterior α-band EEG activity reflect variability in excitability of human visual areas.Cerebr Cortex. 2008; 18: 2010-2018https://doi.org/10.1093/cercor/bhm229Crossref PubMed Scopus (510) Google Scholar,[9]Romei V. Gross J. Thut G. Sounds reset rhythms of visual cortex and corresponding human visual perception.Curr Biol. 2012; 22: 807-813https://doi.org/10.1016/j.cub.2012.03.025Abstract Full Text Full Text PDF PubMed Scopus (177) Google Scholar], however, this estimate was based on a single study with only four participants [[5]Kammer T. Puls K. Erb M. Grodd W. Transcranial magnetic stimulation in the visual system. II. Characterization of induced phosphenes and scotomas.Exp Brain Res. 2005; 160: 129-140https://doi.org/10.1007/s00221-004-1992-0Crossref PubMed Scopus (121) Google Scholar]. Yet, to the best of our knowledge there is no systematic estimate to date, that can inform TMS studies that aim to evoke phosphenes, as to the expected rates of successful and failed phosphene induction. Therefore, here, we systematically identified studies that used early visual cortex TMS to evoke phosphenes, with the aim of determining the expected prevalence of successful phosphene induction and, respectively, the anticipated attrition rate. After systematically searching the literature, we identified 95 studies that have used early visual cortex TMS on healthy human participants, which also provided data regarding the success or failure of phosphene induction. Details regarding the search strategy and the identified studies are provided in the supplementary material. These 95 studies provided data from a total sample size of 1939 participants, out of which 1435 have reported the successful experience of perceiving phosphenes. To calculate the prevalence of phosphenes (θ) we used Bayesian estimation (Fig. 1A). Specifically, we built a model that was informed by a Beta distribution with its parameters α and β set to 1, such that θ ∼ Beta (α = 1, β = 1). This prior distribution was chosen because it creates a uniform distribution, which means that equal probabilities are assigned to any possible prevalence percentage. Next, we calculated the binomial distribution for participants experiencing phosphenes (k), which was given by the probability θ for the total sample (n) in each study (i), which is expressed as ki ∼ Binomial (θ, ni). Following the model above, we were able to compute the posterior probability by implementing Markov chain Monte Carlo sampling. The posterior probability provided us with the estimated prevalence of phosphene induction (Fig. 1B). The posterior probability had a mean of 0.74 (95% Credible Interval = [0.72, 0.76]). This reveals that approximately 74% of participants can perceive phosphenes and, respectively, a 26% attrition rate should be expected for TMS studies relying on phosphene induction. Put simply, researchers and other stakeholders should expect that one in four participants will fail to report reliable phosphene experiences. To date, and as far as we are conversant, this is the first systematic attempt to calculate phosphene prevalence. Our findings revealed that one in four (approximately 26%) healthy participants will most likely fail to perceive any phosphenes during early visual cortex TMS. This estimate is smaller compared to previous estimates (up to 40% failure in perceiving phosphenes), which were based on single studies with a small sample (e.g., 4 participants in [[5]Kammer T. Puls K. Erb M. Grodd W. Transcranial magnetic stimulation in the visual system. II. Characterization of induced phosphenes and scotomas.Exp Brain Res. 2005; 160: 129-140https://doi.org/10.1007/s00221-004-1992-0Crossref PubMed Scopus (121) Google Scholar]). Conclusively, we provide an informative insight, which can guide future TMS research. Having an expected attrition rate is important for numerous reasons, such as allocating and saving resources, planning and organizing studies as well as study proposals, and having adequate statistical power and meaningful results [[10]Molenberghs G. Kenward M. Missing data in clinical studies. John Wiley & Sons, 2007Crossref Scopus (760) Google Scholar]. Based on our findings, we can anticipate approximately one out of four participants to be unable to report phosphenes during early visual cortex TMS. The authors declare no conflict of interest. The following is the Supplementary data to this article: Download .docx (.08 MB) Help with docx files Multimedia component 1

Neuropsychology is a fast-growing specialty in Greece. This study surveyed the status of neuropsychologists in Greece investigating several aspects of the profession. An online-based questionnaire collected data from December 2019 to February 2020. A total of 133 participants specialized in neuropsychology were included in the final sample: 81% of the participants were women with a mean age of 35 years. In the total sample, 25.8% of the participants reported working in the hospital system, 18.5% in the university or college, and 17.7% in a private practice job. Greek professionals cited to engage actively in assessment (87.9%), in research (65.1%), in rehabilitation (47.7%), and teaching (30.2%). Professionals primarily declared to assess individuals with dementia (80.3%), depression (47.7%), and stroke (44.0%), and they reported neurologists, psychiatrists and psychologists as their leading sources of referrals. The top five perceived barriers to the field include the lack of recognized specialty (75.9%), the lack of clinical training opportunities (63.9%), the lack of strong professional associations (57.9%), the lack of access to neuropsychological instruments (57.9%) and the lack of willingness to collaborate between professionals (48.9%). The average monthly income of professionals represents a ratio of 0.76 in comparison to that of other scientists in the country and is the lowest reported among other countries. Despite the significant development of the profession, it is essential to create more clinical training opportunities, apply practices systematically to diverse populations, redefine the specialty of neuropsychology in the national health system of the country, and advocate for the profession.

Sensory visual areas are involved in encoding information in visual short-term memory (VSTM). Yet it remains unclear whether sensory visual cortex is a necessary component of the brain network for maintenance of information in VSTM. Here, we aimed to systematically review studies that have investigated the role of the sensory visual cortex in VSTM using transcranial magnetic stimulation (TMS) and to quantitatively explore these effects using meta-analyses. Fourteen studies were identified and reviewed. Eight studies provided sufficient data for meta-analysis. Two meta-analyses, one regarding the VSTM encoding phase (17 effect sizes) and one regarding the VSTM maintenance phase (15 effect sizes), two meta-regressions (32 effect sizes in each), and one exploratory meta-analysis were conducted. Our results indicate that the sensory visual cortex is similarly involved in both the encoding and maintenance VSTM phase. We suggest that some cases where evidence did not show significant TMS effects was due to low memory or perceptual task demands. Overall, these findings support the idea that sensory visual areas are part of the brain network responsible for successfully maintaining information in VSTM.

Episodic memory decline is the prominent neuropsychological feature of typical Alzheimer's Disease (AD), for which current treatments have a limited clinical response. Recently, gamma entrainment therapy has been used as a non-invasive treatment in AD, providing evidence that it may have the potential to alleviate brain pathology and improve cognitive function in AD patients. At the same time, the precuneus (PC) has been recognized as a key area involved in AD related memory deficits and as a key node of the Default Mode Network. This study aimed to investigate the effectiveness of a 40 Hz Transcranial Magnetic Stimulation (TMS) intervention, delivered bilaterally to the precuneus for 10 days, in improving the patients' episodic memory performance. Secondary outcome variables investigated included general cognitive function, semantic and spatial memory, as well as attention and executive function. A concurrent multiple baseline design across five cases was employed. Four patients completed the study. Visual analysis combined with effect size indices were used to evaluate changes across phases. An increase in the average level of immediate recalled words was observed in three out of four patients. Effect size indices indicated significant improvement of attention skills in two patients. No treatment effect was observed for semantic and visual memory, or for executive function. An immediate treatment effect was observed in all patients' general cognitive function as assessed with the Alzheimer's Disease Assessment Scale (mean reduction of 5 points), which was maintained and improved further three months post-treatment. The neuropsychological evaluations indicated improved performance three months post-treatment in immediate and delayed recall, attention, phonological verbal fluency, anxiety, and neuropsychiatric symptoms. This study provides preliminary evidence for the efficacy of a novel non-pharmacological treatment using gamma-band TMS in addressing cognitive dysfunction in AD.

Despite decades of research, Alzheimer’s Disease (AD) remains a lethal neurodegenerative disorder for which there are no effective treatments. This review examines the latest evidence of a novel and newly introduced perspective, which focuses on the restoration of gamma oscillations and investigates their potential role in the treatment of AD. Gamma brain activity (∼25–100 Hz) has been well-known for its role in cognitive function, including memory, and it is fundamental for healthy brain activity and intra-brain communication. Aberrant gamma oscillations have been observed in both mice AD models and human AD patients. A recent line of work demonstrated that gamma entrainment, through auditory and visual sensory stimulation, can effectively attenuate AD pathology and improve cognitive function in mice models of the disease. The first evidence from AD patients indicate that gamma entrainment therapy can reduce loss of functional connectivity and brain atrophy, improve cognitive function, and ameliorate several pathological markers of the disease. Even though research is still in its infancy, evidence suggests that gamma-based therapy may have a disease-modifying effect and has signified a new and promising era in AD research.