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Dementia is a global public health problem with increasing prevalence and incidence worldwide. The African continent is expected to bear the biggest brunt of the burden of dementia by 2050 because of the rapid demographic changes, including rapid population growth, an increase in life expectancy, and ageing. However, French-speaking Sub-Saharan African (FS-SSA) countries are underrepresented in research on dementia in Africa. While the reasons are diverse and complex, linguistic and cultural barriers to research, disproportionately affect these countries and may be significant factors. Any efforts, therefore, to redress the burden of dementia in Africa must consider the specific demographic, cultural, and linguistic characteristics of FS-SSA countries. This scoping review explores the current state of knowledge in dementia and cognitive impairment in Sub-Saharan Africa, highlighting research gaps and specific patterns unique to FS-SSA Africa. We identify pathways for research to bridge the knowledge gaps on dementia in FS-SSA as part of the global endeavor to tackle dementia worldwide.

Background: Patient and Public Involvement (PPI) in aphasia research obliges researchers to include people with aphasia (PWA) as research partners from the beginning of the study. Yet the quality of reporting on the level and type of involvement is poorly documented in the absence of a guideline to document contribution. This study aimed to extract the items and statements relevant for the development of the People with Aphasia and Other Layperson Involvement (PAOLI) reporting guideline, in collaboration with people with aphasia. Method: The EQUATOR method for developing a reporting guideline was followed. This involved: (1) evidence from a scoping review, (2) a thematic analysis of the in-depth interviews, of people with stroke and aphasia, on the topics to be included in the pilot draft, (3) a two round Delphi survey for item/statement selection and (4) an experts’ consensus meeting. The research team involved two PPI partners with chronic stroke-induced aphasia. The research process involved co-design and was informed by the Dialogue model. Results: Twenty-three participants, from 13 countries, voted in round one with 87% (20/23) responding in round two. The PAOLI guideline includes 17 items (with 66 descriptive statements) on how to: establish collaborations, recruit patients, gain informed consent, organize induction meetings, train patient partners, create communication links, engage communication partners, conceptualize topics, establish research priorities, reach consensus, work with co-design methods, develop proposals, assist with dissemination of results, promote implementation of the outcomes, support patient partners and promote self-evaluation, monitor progress and assess impact of the patient involvement. These items were considered by the participants as the most important for the involvement of people with aphasia as research partners. Conclusion: The PAOLI is the first international consensus guideline for reporting patient involvement in aphasia research. Researchers are encouraged to adopt the reporting guideline to improve the quality of their research by documenting the meaningful involvement of people with aphasia within the research team from the start.

Background Evidence-based assessments for people with aphasia (PWA) in Greek are predominantly impairment based. Functional communication (FC) is usually underreported and neglected by clinicians. This study explores the adaptation and psychometric testing of the Greek (GR) version of The Scenario Test. The test assesses the everyday FC of PWA in an interactive multimodal communication setting. Aims To determine the reliability and validity of The Scenario Test-GR and discuss its clinical value. Methods & Procedures The Scenario Test-GR was administered to 54 people with chronic stroke (6+ months post-stroke): 32 PWA and 22 stroke survivors without aphasia. Participants were recruited from Greece and Cyprus. All measures were administered in an interview format. Standard psychometric criteria were applied to evaluate reliability (internal consistency, test–retest, and interrater reliability) and validity (construct and known-groups validity) of The Scenario Test-GR. Outcomes & Results The Scenario Test-GR shows high levels of reliability and validity. High scores of internal consistency (Cronbach's α = 0.95), test–retest reliability (intra-class coefficients (ICC) = 0.99), and interrater reliability (ICC = 0.99) were found. Interrater agreement in scores on individual items ranged from good to excellent levels of agreement. Correlations with a tool measuring language function in aphasia, a measure of FC, two instruments examining the psychosocial impact of aphasia and a tool measuring non-verbal cognitive skills revealed good convergent validity (all ps < 0.05). Results showed good known-groups validity (Mann–Whitney U = 96.5, p < 0.001), with significantly higher scores for participants without aphasia compared with those with aphasia. Conclusions & Implications The psychometric qualities of The Scenario Test-GR support the reliability and validity of the tool for the assessment of FC in Greek-speaking PWA. The test can be used to assess multimodal FC, promote aphasia rehabilitation goal-setting at the activity and participation levels, and be used as an outcome measure of everyday communication abilities.

Background: Alzheimer's disease (AD) remains to date an incurable disease with a long asymptomatic phase. Early diagnosis in peripheral biofluids has emerged as key for identifying subjects at risk and developing therapeutics and preventative approaches., Objective: We apply proteomics discovery to identify salivary diagnostic biomarkers for AD, which are suitable for self-sampling and longitudinal biomonitoring during aging., Methods: 57 participants were recruited for the study and were categorized into Cognitively normal (CNh) (n = 19), mild cognitive impaired (MCI) (n = 21), and Alzheimer's disease (AD) (n = 17). On a subset of subjects, 3 CNh and 3 mild AD, shot-gun filter aided sample preparation (FASP) proteomics and liquid chromatography mass spectroscopy (LC-MS/MS) was employed in saliva and cerebrospinal fluid (CSF) to identify neural-derived proteins. The protein level of salivary Transthyretin (TTR) was validated using western blot analysis across groups., Results: We found that 19.8% of the proteins in saliva are shared with CSF. When we compared the saliva and CSF proteome, 24 hits were decreased with only one protein expressed more. Among the differentially expressed proteins, TTR with reported function in amyloid misfolding, shows a significant drop in AD samples, confirmed by western blot showing a 0.5-fold reduction in MCI and AD compared to CNh., Conclusion: A reduction in salivary TTR appears with the onset of cognitive symptoms. More in general, the proteomic profiling of saliva shows a plethora of biomarkers worth pursuing as non-invasive hallmarks of dementia in the preclinical stage.

This review focuses on embodied semantic theories of language, which assume a concomitant activation of sensorimotor areas during verbal processing. Behavioural and functional studies showing the influence of semantic treatment on perceptuo- and sensori-motor cortices are here presented. We focus on embodiment of the second language (L2) in bilingual subjects which, contrary to the native language (L1) embodiment, has been much less addressed. After providing current models of bilingual language processing, we will consider factors which may explain different depths of embodiment of L2, as observed in several studies. In particular, we will provide insight into proficiency (i.e. the ability one has in L2 usage), immersion (i.e. the degree of exposure to L2) and the age of acquisition of L2. We will also provide suggestions regarding the potential expansion of knowledge in this domain: embodied semantics research in bilinguals might give a boost to therapeutic approaches to the rehabilitation of bilingual aphasic patients. Lastly, considerations are presented about theoretical as well as practical implications for translation research.

Zusammenfassung. Psychotische Erkrankungen im Alter umfassen ein grosses Spektrum an Ursachen und Manifestationen. Häufig treten sie im Rahmen einer Depression, einer demenziellen Entwicklung, eines Substanz- und Medikamentenmissbrauchs oder eines Delirs auf. Während im Alter neue Erkrankungen auftreten können, erreichen zunehmend auch mehr Personen mit langjährig bestehenden, chronisch psychotischen Störungen das höhere Lebensalter. Neben psychotischen Störungen sind im Alter kognitive und somatische Beeinträchtigungen häufig, weshalb eine Fremdanamnese unverzichtbar ist. Die krankheitsbedingt veränderten Lebensumstände, die Komplexität und die jeweils individuelle Situation gilt es bei der Diagnostik und Therapie zu integrieren. Die vorliegenden Empfehlungen sind unter der Federführung der Schweizerischen Gesellschaft für Alterspsychiatrie und -psychotherapie (SGAP) in Zusammenarbeit mit den akademischen Fachgesellschaften für gerontologische und psychiatrische Pflege des Vereins für Pflegewissenschaft und weiteren Fachverbänden entstanden. Ziel ist es, den aktuellen Stand des Wissens über die psychotischen Erkrankungen im Alter sowie über die Möglichkeiten der Diagnostik und Therapie zusammenzufassen und den interprofessionellen, klinischen Teams in der stationären und ambulanten Versorgung zur Verfügung zu stellen.

Lexical stress is an essential element of prosody. Mastering this prosodic feature is challenging, especially in a stress-free foreign language for individuals native to a stress-fixed language, a phenomenon referred to as stress deafness. By using functional magnetic resonance imaging, we elucidated the neuronal underpinnings of stress processing in a stress-free foreign language, and determined the underlying mechanism of stress deafness. Here, we contrasted behavioral and hemodynamic responses revealed by native speakers of a stress-free (German;N= 38) and a stress-fixed (French;N= 47) language while discriminating pairs of words in a stress-free foreign language (Spanish). Consistent with the stress deafness phenomenon, French speakers performed worse than German speakers in discriminating Spanish words based on cues of stress but not of vowel. Whole-brain analyses revealed widespread bilateral networks (cerebral regions including frontal, temporal and parietal areas as well as insular, subcortical and cerebellar structures), overlapping with the ones previously associated with stress processing within native languages. Moreover, our results provide evidence that the structures pertaining to a right-lateralized attention system (i.e., middle frontal gyrus, anterior insula) and the Default Mode Network modulate stress processing as a function of the proficiency level. In comparison to the German speakers, the French speakers activated the attention system and deactivated the Default Mode Network to a stronger degree, reflecting attentive engagement, likely a compensatory mechanism underlying the “stress-deaf” brain. The mechanism modulating stress processing argues for a rightward lateralization, indeed overlapping with the location covered by the dorsal stream but remaining unspecific to speech.

According to embodied theories, motor and language processing bidirectionally interact: Motor activation modulates behavior in lexico-semantic tasks (semantic resonance), and understanding motor-related words entails activation of the corresponding motor brain areas (motor resonance). Whereas many studies investigated such interaction in the first language (L1), only few did so in a second language (L2), focusing on motor resonance. Here, we directly compared L1 and a late L2, for the first time both in terms of semantic and motor resonance and both in terms of magnitude and timing, by taking advantage of single-pulse TMS. Twenty-five bilinguals judged, in each language, whether hand motor-related (“grasp”) and non-motor-related verbs (“believe”), were physical or mental. Meanwhile, we applied TMS on the hand motor cortex at 125, 275, 350, and 500 msec post verb onset, and recorded behavioral responses and TMS-induced motor evoked potentials. TMS induced faster responses for L1 versus L2 motor and nonmotor verbs at 125 msec (three-way interaction β = −0.0442, 95% CI [0.0814, −0.0070]), showing a semantic resonance effect at an early stage of word processing in L1 but not in L2. Concerning motor resonance, TMS-induced motor evoked potentials at 275 msec revealed higher motor cortex excitability for L2 versus L1 processing (two-way interaction β = 0.095, 95% CI [0.017, 0.173]). These findings confirm action–language interaction at early stages of word recognition, provide further evidence that L1 and L2 are differently embodied, and call for an update of existing models of bilingualism and embodiment, concerning both language representations and processing.

This scientific commentary refers to ‘Unclassified fluent variants of primary progressive aphasia: distinction from semantic and logopenic variants’ by Watanabe et al. (https://doi.org/10.1093/braincomms/fcac015)

We propose a method of orthographic visualisation strategy in a poststroke severe aphasia person with dissociation between oral and written expression. fMRI results suggest that such strategy may induce the engagement of alternative nonlanguage networks and visual representations may help improving oral output. This choice of rehabilitation method can be based on the remaining capacities and, therefore, on written language. Most notably, no study so far addressed how orthographic visualisation strategy during speech rehabilitation might influence clinical outcomes in nonfluent aphasia and apraxia patients.

In bilinguals, language proficiency has been advanced to influence the involvement of domain-general control networks in language selection. We assessed, in university student translators with moderate- to high-second language (L2) proficiency depending on their translation educational level, the functional activity in the key language and control areas (the caudate nucleus, anterior cingulate, and prefrontal cortex), during task- and language-selection in an oral production context. We found that L2 proficiency influenced the relative involvement of our regions of interest during language selection vs domain-general cognitive control processes. While the left middle frontal and left caudate areas were more involved during linguistic than alphanumeric task selection in the low L2 proficiency group, these regions were similarly involved in both tasks in the high-L2 proficiency group. These findings suggest that language selection relies primarily on a network within domain-general cognitive control system with an increase in resource needs when L2 proficiency is low.

Primary progressive aphasia (PPA) is a neurodegenerative disorder with a progressive loss of language. Long-term support requires speech therapy but also individually set training programs. Here we propose an 8-month individualized speech-training program which alternates 3-week periods of transcranial direct current stimulation (tDCS) treatment with intensive daily language exercises and a 3-week period without tDCS treatment and a less intensive language exercise from home in a patient with non-fluent variant PPA (nfvPPA). The endpoints were the following: adherence to this program, language data after 8 months, questionnaires related to emotional valence, and brain volume changes. The results showed a persistent adherence after 8 months and a positive compliance reported by both the patient and the partner. The language evaluation showed a clinical stabilization. Moreover, a significant and positive influence of tDCS on mood was observed. This is, to our knowledge, the first ever published report of a combined neuromodulation and language training during the course of 8 months. Our finding suggests the feasibility of programs integrating hospital speech therapy, home training, and tDCS modulation in PPA. Further studies should be conducted in order to disentangle the contextual influences on language performance from the tDCS intervention effects and to address the observation of an initial improvement and a subsequent stabilization effect of language performances.

This study aims to determine which factors within the first week after a first-ever transient ischemic attack (TIA) or minor ischemic stroke (MIS) are associated with stroke survivors’ ability to return to either partial or full time paid external work (RTpW). In this single-center prospective cohort study, we recruited 88 patients with first-ever TIA or MIS (NIHSS ≤ 5). Bivariate analyses were conducted between patients that did (RTpW) or did not return to paid work (noRTpW) within 7 days after stroke onset and at 3-months follow-up. Then, we conducted multivariate logistic and negative binomial regression analyses assessing (i) which factors are associated with RTpW at 3 months (ii) the likelihood that patients would RTpW at 3 months and (iii) the number of months necessary to RTpW. Overall, 43.2% of the patients did not RTpW at 3 months. At 3-months follow-up, higher anxiety/depression and fatigue-related disabilities were associated with noRTpW. Multivariate analysis showed that higher NIHSS scores at onset and hyperlipidemia (LDL cholesterol > 2.6 mmol/L or statins at stroke onset) were associated with noRTpW at 3 months. Stroke severity and/or newly diagnosed hypercholesterolemia at stroke onset in TIA or MIS patients were associated with not returning to paid work at 3 months.

Background Obsessive-compulsive disorder (OCD) is characterized by intrusive and irrational thoughts as well as repetitive behaviours. OCD-like behaviours have been described in a wide range of neurological disorders. In cerebrovascular accidents, the semiology arises mostly from lesions to the basal ganglia – though cortical regions may also be involved. In the past few years, the mechanisms underlying OCD in psychiatric patients have been re-examined, in particular the functional relationship between anxiety, obsessions and compulsions. Traditionally, obsessions are viewed as a trigger for compulsive behaviour that represents an attempt to reduce anxiety. By contrast, other models place compulsions – as a manifestation of an imbalance between goal-directed action and automatic habits that leads to maladaptive habit learning – at the core of OCD. CASE: We show neurological evidence of pure compulsions without obsession in a patient following stroke in the left subcortical regions. Furthermore, we present comprehensive neuropsychological findings that identify specific alterations across executive and emotional domains. Finally, MRI analyses reveal that the subcortical stroke had resulted in a strong decrease of connectivity suggestive of large network alterations. CONCLUSIONS: Our case provides direct information on how brain structure and function relate in an OCD patient, highlighting the central role of compulsions in the pathology.

Background and Aims: Timely administration of recombinant tissue plasminogen activator (r-tPA) improves clinical outcomes in acute ischemic stroke patients. This study aims to explore the influence of the systematic presence on site of a neurologist compared with telestroke management on door-to-needle time in acute ischemic stroke outside of working hours (OWH).Methods: This retrospective cohort study included all r-tPA-treated patients in the emergency rooms of two Swiss stroke units, Nyon Hospital [Groupement Hospitalier de l'Ouest Lémanique (GHOL)] and Fribourg Hospital [Hôpital de Fribourg (HFR)], between February 2014 and September 2018. Door-to-needle time was analyzed for patients admitted during working hours (WH' weekdays 08:00–18:00) and OWH (weekdays 18:00–08:00, weekends, and public holidays). The latter was compared between centers; OWH, every patient was evaluated prior to thrombolysis by a neurologist on site in GHOL, while HFR adopted distance neurological supervision with teleradiology, performed by telephone evaluation of relevant clinical information with online real-time access to brain imaging.Results: Data were analyzed for 157 patients in HFR and 101 patients in GHOL. No statistically significant differences in baseline characteristics were found for the 258 r-tPA-treated acute ischemic stroke patients, in terms of age, gender, cardiovascular risk factors (hypertension, diabetes, and atrial fibrillation), and pre-Modified Rankin Scale (pre-mRs) between centers, with the exception of smoking and anticoagulation status. Patients in HFR presented with more severe strokes {median National Institutes of Health Stroke Scale (NIHSS) [6 (SD 6.88) (GHOL), 8 (SD 6.98) (HFR), p = 0.005]}. No significant differences in baseline characteristics were found as per admission time independently of the center. Door-to-needle time was significantly longer in the HFR cohort when compared with GHOL, irrespective of admission time. Both centers demonstrated significantly longer median door-to-needle time OWH. However, analysis of the door-to-needle time differences between WH and OWH showed no significant interaction using robust ANCOVA WRS2 analysis (p = 0.952) and a Bayesian model (BF01 = 3.97).Conclusions: On-site systematic evaluation by a neurologist did not appear to influence door-to-needle time OWH, suggesting distance supervision may be time-efficient in thrombolysis. This supports existing prospective studies in hyperacute telestroke management. The relevance lies in optimizing resource use considering the increasing demand for emergency neurological management.

This preliminary investigation aimed to assess beta (β) oscillation, a marker of the brain GABAergic signaling, as a potential objective pain marker, hence contributing at the same time to the mechanistic approach of pain management. This case–control observational study measured β electroencephalographic (EEG) oscillation in 12 right-handed adult male with chronic neuropathic pain and 10 matched controls (∼55 years). Participants were submitted to clinical evaluation (pain visual analog scale, Hospital Anxiety, and Depression scale) and a 24-min high-density EEG recording (BIOSEMI). Data were analyzed using the EEGlab toolbox (MATLAB), SPSS, and R. The global power spectrum computed within the low (Lβ, 13–20 Hz) and the high (Hβ, 20–30 Hz) β frequency sub-bands was significantly lower in patients than in controls, and accordingly, Lβ was negatively correlated to the pain visual analog scale (R = −0.931, p = 0.007), whereas Hβ correlation was at the edge of significance (R = −0.805; p = 0.053). Patients’ anxiety was correlated to pain intensity (R = 0.755; p = 0.003). Normalization of the low and high β global power spectrum (GPS) to the GPS of the full frequency range, while confirming the significant Lβ power decrease in chronic neuropathic pain patients, vanished the significance of the Hβ decrease, as well as the correlation between Lβ power and pain intensity. Our results suggest that the GABAergic Lβ EEG oscillation is affected by chronic neuropathic pain. Confirming the Lβ GPS decrease and the correlation with pain intensity in larger studies would open new opportunities for the clinical application of gamma-aminobutyric acid-modifying therapies.

Introduction There is increasing evidence linking periodontal infections to Alzheimer's disease (AD). Saliva sampling can reveal information about the host and pathogen interactions that can inform about physiological and pathological brain states. Methods A cross‐sectional cohort of age‐matched participants (78) was segmented according to their chemosensory (University of Pennsylvania Smell Identification Test; UPSIT) and cognitive scores (Mini‐Mental State Exam; MMSE and clinical dementia rating; CDR). Mid‐morning saliva was sampled from each participant and processed for microbiome composition and cytokine analysis. Linear discriminant analysis (LDA) was used to unravel specific changes in microbial and immunological signatures and logistic regression analysis (LRA) was employed to identify taxa that varied in abundance among patient groups. Results Using olfaction we distinguish in the cognitively normal population a segment with high chemosensory scores (CNh, 27) and another segment with chemosensory scores (CNr, 16) as low as mild cognitive impairment (MCI, 21) but higher than the AD group (17). We could identify stage‐specific microbial signatures changes but no clearly distinct cytokine profiles. Periodontal pathogen species as Filifactor villosus decline with the increasing severity of AD, whereas opportunistic oral bacteria such as Leptotrichia wadei show a significant enrichment in MCI. Conclusions The salivary microbiome indicates stage‐dependent changes in oral bacteria favoring opportunistic species at the expense of periodontal bacteria, whereas the inflammatory profiles remain mainly unchanged in the sampled population.

From birth, the human visual system shows a remarkable sensitivity for perceiving biological motion. This visual ability relies on a distributed network of brain regions and can be preserved even after damage of high-level ventral visual areas. However, it remains unknown whether this critical biological skill can withstand the loss of vision following bilateral striate damage. To address this question, we tested the categorization of human and animal biological motion in BC, a rare case of cortical blindness after anoxia-induced bilateral striate damage. The severity of his impairment, encompassing various aspects of vision (i.e., color, shape, face, and object recognition) and causing blind-like behavior, contrasts with a residual ability to process motion. We presented BC with static or dynamic point-light displays (PLDs) of human or animal walkers. These stimuli were presented either individually, or in pairs in two alternative forced choice (2AFC) tasks. When confronted with individual PLDs, the patient was unable to categorize the stimuli, irrespective of whether they were static or dynamic. In the 2AFC task, BC exhibited appropriate eye movements towards diagnostic information, but performed at chance level with static PLDs, in stark contrast to his ability to efficiently categorize dynamic biological agents. This striking ability to categorize biological motion provided top-down information is important for at least two reasons. Firstly, it emphasizes the importance of assessing patients' (visual) abilities across a range of task constraints, which can reveal potential residual abilities that may in turn represent a key feature for patient rehabilitation. Finally, our findings reinforce the view that the neural network processing biological motion can efficiently operate despite severely impaired low-level vision, positing our natural predisposition for processing dynamicity in biological agents as a robust feature of human vision.

The role of the sensorimotor system in second language (L2) semantic processing as well as its clinical implications for bilingual patients has hitherto been neglected. We offer an overview of the issues at stake in this under-investigated field, presenting the theoretical and clinical relevance of studying L2 embodiment and reviewing the few studies on this topic. We highlight that (a) the sensorimotor network is involved in L2 processing, and that (b) in most studies, L2 is differently embodied than L1, reflected in a lower degree or in a different pattern of L2 embodiment. Importantly, we outline critical issues to be addressed in order to guide future research. We also delineate the subsequent steps needed to confirm or dismiss the value of language therapeutic approaches based on embodiment theories as a complement of speech and language therapies in adult bilinguals.

In neurology and neuropsychology, behavior refers to the way human beings act and make decisions in contact with their environment. Behavioral impairment is therefore defined as a pathology, following brain lesion, that impacts the interactions between the brain-lesioned individual and his/her surrounding social world. First descriptions of behavioral disorders, including neuroanatomical correlates, date back to the mid-19th century. However, attempts towards their systematic identification and analysis only began at the turn of the 19th to 20th century. In this chapter, we shall span 3 main themes by introducing the first case reports based on thorough clinical descriptions, dating back to the 19th century. We then examine the emergence of checklist questionnaires and their application to large cohorts of individuals starting after World War II. Finally, we outline how, over the last 3 decades, the pace has significantly accelerated in the pursuit of defining the fine-grained processes underlying behavioral functioning, as well as the development of new and more complex measures, along with the emergence of the social cognition and social brain concepts. As the assessment tools have expanded and become more specific, an increasing complexity of mechanisms underlying behavior has begun to emerge.

Background: Cameroon was not spared by the coronavirus 2019 (COVID-19) pandemic, prompting the Cameroonian government to implement nationwide measures to stall viral transmission. However little is known about how well these unprecedented measures are being observed as the pandemic evolves. Methods: We conducted a six-month online survey to assess the preventive behaviour of Cameroonian adults during the COVID-19 outbreak. Sociodemographic data and personal history of respondents were obtained, and a 5-point adherence score was constructed based on self-reported observance of the following preventive measures: physical distancing, face mask use, hand hygiene, not touching one’s face, and covering the mouth when coughing or sneezing. Predictors of adherence were investigated using ordinal logistic regression models. Findings: Overall, 7,381 responses from all ten regions of Cameroon were analysed (mean age: 32·8±10·8; 73·3% male). During the two weeks preceding participation in the survey, 20 of the 496 tested respondents were positive for COVID-19 (positivity rate: 4·0%). Overall mean adherence score was 3·96±1·11 on a scale of 0–5. Mean weekly adherence scores were initially high, but gradually decreased over time accompanied by increasing incidence of COVID-19 during the last study weeks. Multivariable analyses revealed that older persons, those receiving COVID-19 information from health personnel, and those who agreed with the necessity of lockdown measures had higher odds for adherence, while experiencing flu-like symptoms was associated with poor adherence. Interpretation: Pending more permanent solutions like large scale COVID-19 vaccination, continuous observance of preventive measures should be encouraged among Cameroonians to avoid a resurgence in COVID-19 infections. Funding Statement: ERC Advanced Grant (671055) and VLIRUOS (Flemish University cooperation). Declaration of Interests: The authors have no conflicts of interest to declare. Ethics Approval Statement: This study was approved by the National Ethics Committee of Cameroon (Ref: 2020/05/1229/CE/CNERSH/SP of 06.5.20) as well as the Ethics Committee of the University of Antwerp, Belgium (Ref: 20/13/148).

The human turn-taking system regulates the smooth and precise exchange of speaking turns during face-to-face interaction. Recent studies investigated the processing of ongoing turns during conversation by measuring the eye movements of noninvolved observers. The findings suggest that humans shift their gaze in anticipation to the next speaker before the start of the next turn. Moreover, there is evidence that the ability to timely detect turn transitions mainly relies on the lexico-syntactic content provided by the conversation. Consequently, patients with aphasia, who often experience deficits in both semantic and syntactic processing, might encounter difficulties to detect and timely shift their gaze at turn transitions. To test this assumption, we presented video vignettes of natural conversations to aphasic patients and healthy controls, while their eye movements were measured. The frequency and latency of event-related gaze shifts, with respect to the end of the current turn in the videos, were compared between the two groups. Our results suggest that, compared with healthy controls, aphasic patients have a reduced probability to shift their gaze at turn transitions but do not show significantly increased gaze shift latencies. In healthy controls, but not in aphasic patients, the probability to shift the gaze at turn transition was increased when the video content of the current turn had a higher lexico-syntactic complexity. Furthermore, the results from voxel-based lesion symptom mapping indicate that the association between lexico-syntactic complexity and gaze shift latency in aphasic patients is predicted by brain lesions located in the posterior branch of the left arcuate fasciculus. Higher lexico-syntactic processing demands seem to lead to a reduced gaze shift probability in aphasic patients. This finding may represent missed opportunities for patients to place their contributions during everyday conversation.

Background: Screening of aphasia in acute stroke is crucial for directing patients to early language therapy. The Language Screening Test (LAST), originally developed in French, is a validated language screening test that allows detection of a language deficit within a few minutes. The aim of the present study was to develop and validate two parallel German versions of the LAST. Methods: The LAST includes subtests for naming, repetition, automatic speech, and comprehension. For the translation into German, task constructs and psycholinguistic criteria for item selection were identical to the French LAST. A cohort of 101 stroke patients were tested, all of whom were native German speakers. Validation of the LAST was based on (1) analysis of equivalence of the German versions, which was established by administering both versions successively in a subset of patients, (2) internal validity by means of internal consistency analysis, and (3) external validity by comparison with the short version of the Token Test in another subset of patients. Results: The two German versions were equivalent as demonstrated by a high intraclass correlation coefficient of 0.91. Furthermore, an acceptable internal structure of the LAST was found (Cronbach's α = 0.74). A highly significant correlation (r = 0.74, p < 0.0001) between the LAST and the short version of the Token Test indicated good external validity of the scale. Conclusion: The German version of the LAST, available in two parallel versions, is a new and valid language screening test in stroke.

Epilepsy affects at least 50 million individuals worldwide, especially in sub-Saharan Africa (sSA). Cognitive impairment is common in people with epilepsy (PWE) yet, little is known on the burden of cognitive impairment in people with epilepsy in sSA. This study was thus designed to assess cognitive impairment in PWE or epilepsy-associated neurocognitive disorders (EAND) in a rural population in Cameroon.This was a case-control study including PWE and age/sex-matched healthy controls from July to September 2017 in Bilomo, a village in the Mbam and Kim Division. The Montreal Cognitive Assessment (MoCA), International HIV Dementia Scale (IHDS), Dubois' Five Word testing, Frontal Assessment Battery (FAB), Isaac's Set Test and the Clock drawing test were administered to the study participants to evaluate global and specific cognitive functions.Eighty participants were included (40 cases and 40 controls) with a mean age of 25.78 years. Using the MoCA, 87.5% of cases had cognitive impairment, against 37.5% of controls (p 0.001; OR 11.67; CI 3.40-45.09). Using the IHDS, the prevalence of global cognitive impairment was 84.6% among the cases against 40% for the controls (p = 0.001; OR 7.07; CI 2.29-29.19). Specifically, executive function deficits (92.5% of cases vs 40.0% of controls p = 0.001 OR = 18.50 CI; 4.48-105.08) and decreased verbal fluency (100% of cases against 45% of controls p 0.001) were the most affected cognitive domains. Longer duration of epilepsy and higher seizure frequency were associated with global cognitive impairment. Low level of education was associated with both decreased verbal fluency and executive dysfunction while a longer stay in Bilomo correlated with poor results on the Isaac's Set Test.The prevalence of cognitive impairment appears to be much higher in PWE in the Mbam valley, particularly decreased executive function and verbal fluency, than in people without epilepsy. Longer disease duration, higher seizure frequency, low level of education and length of stay in Bilomo are associated with poorer cognitive performance. More studies are needed to refine evaluation tools to better characterize and manage EAND in sSA.

In neurology and neuropsychology, behavior refers to the way human beings act and make decisions in contact with their environment. Behavioral impairment is therefore defined as a pathology, following brain lesion, that impacts the interactions between the brain-lesioned individual and his/her surrounding social world. First descriptions of behavioral disorders, including neuroanatomical correlates, date back to the mid-19th century. However, attempts towards their systematic identification and analysis only began at the turn of the 19th to 20th century. In this chapter, we shall span 3 main themes by introducing the first case reports based on thorough clinical descriptions, dating back to the 19th century. We then examine the emergence of checklist questionnaires and their application to large cohorts of individuals starting after World War II. Finally, we outline how, over the last 3 decades, the pace has significantly accelerated in the pursuit of defining the fine-grained processes underlying behavioral functioning, as well as the development of new and more complex measures, along with the emergence of the social cognition and social brain concepts. As the assessment tools have expanded and become more specific, an increasing complexity of mechanisms underlying behavior has begun to emerge.

The role of nonverbal communication in patients with post-stroke language impairment (aphasia) is not yet fully understood. This study investigated how aphasic patients perceive and produce co-speech gestures during face-to-face interaction, and whether distinct brain lesions would predict the frequency of spontaneous co-speech gesturing. For this purpose, we recorded samples of conversations in patients with aphasia and healthy participants. Gesture perception was assessed by means of a head-mounted eye-tracking system, and the produced co-speech gestures were coded according to a linguistic classification system. The main results are that meaning-laden gestures (e.g., iconic gestures representing object shapes) are more likely to attract visual attention than meaningless hand movements, and that patients with aphasia are more likely to fixate co-speech gestures overall than healthy participants. This implies that patients with aphasia may benefit from the multimodal information provided by co-speech gestures. On the level of co-speech gesture production, we found that patients with damage to the anterior part of the arcuate fasciculus showed a higher frequency of meaning-laden gestures. This area lies in close vicinity to the premotor cortex and is considered to be important for speech production. This may suggest that the use of meaning-laden gestures depends on the integrity of patients’ speech production abilities.

Based on findings for overlapping representations of bilingual people's first (L1) and second (L2) languages, unilingual therapies of bilingual aphasia have been proposed to benefit the untrained language. However, the generalisation patterns of intra- and cross-language and phonological therapy and their neural bases remain unclear. We tested whether the effects of an intensive lexical-phonological training (LPT) in L2 transferred to L1 word production in a Persian-French bilingual stroke patient with Broca's aphasia. Language performance was assessed using the Bilingual Aphasia Test, a 144-item picture naming (PN) task and a word–picture verification (WPV) task. Electroencephalography (EEG) was recorded during PN and WPV in both languages before and after an LPT in French on a wordlist from the PN task. After the therapy, naming improved only for the treated L2 items. The naming performance improved neither in the untrained L2 items nor in the corresponding items in L1. EEG analyses revealed a Language x Session topographic interaction at 540 ms post-stimulus, driven by a modification of the electrophysiological response to the treated L2 but not L1 items. These results indicate that LPT modified the brain networks engaged in the phonological-phonetic processing during naming only in the trained language for the trained items.

After immobilization, patients show impaired postural control and increased risk of falling. Therefore, loss of balance control should already be counteracted during immobilization. Previously, studies have demonstrated that both motor imagery (MI) and action observation (AO) can improve motor performance. The current study elaborated how the brain is activated during imagination and observation of different postural tasks to provide recommendations about the conception of non-physical balance training. For this purpose, participants were tested in a within-subject design in an fMRI-scanner in three different conditions: (a) AO + MI, (b) AO, and (c) MI. In (a) participants were instructed to imagine themselves as the person pictured in the video whereas in (b) they were instructed simply to watch the video. In (c) subjects closed their eyes and kinesthetically imagined the task displayed in the video. Two tasks were evaluated in each condition: (i) static standing balance and (ii) dynamic standing balance (medio-lateral perturbation). In all conditions the start of a new trial was indicated every 2 sec by a sound.During AO + MI of the dynamic task, participants activated motor centers including the putamen, cerebellum, supplementary motor area, premotor cortices (PMv/d) and primary motor cortex (M1). MI showed a similar pattern but no activity in M1 and PMv/d. In the SMA and cerebellum, activity was generally higher in the dynamic than in the static condition. AO did not significantly activate any of these brain areas.Our results showed that (I) mainly AO + MI, but also MI, activate brain regions important for balance control; (II) participants display higher levels of brain activation in the more demanding balance task; (III) there is a significant difference between AO + MI and AO. Consequently, best training effects should be expected when participants apply MI during AO (AO + MI) of challenging postural tasks.

Background Huntington's disease (HD) is characterized by early involvement of the striatum. It affects the pace of repetitive motor activity, as motor timing depends on basal ganglia activity. However, data are lacking on the impact of this process on auditory time perception in motor non-affected gene carriers. Objective This work aims to test the performance in time perception of a group of mutation carriers, either without motor symptoms or at an early stage of motor involvement. This should allow designing therapies targeting compensation strategies and possibly be used as a disease progression marker. Method Time was assessed using two different tasks. An absolute, duration-based time perception was assessed in a first task and a relative, beat-based time perception was assessed in a second one. HD-mutation carriers with low-to-middle grades of motor involvement (HD-motor, n = 10) or without motor signs (HD-premotor n = 21), were compared with age- and sex-matched healthy controls (control (n = 27)). Thresholds of time difference perception where assessed. Results For both tasks, poorer performances were found in HD-motor patients as compared with HD-premotor and controls. Thresholds of time difference perception correlated positively with the CAP score for the whole group of HD-gene carriers in both tasks. In a post-hoc exploratory analysis performed by a multiple regression, a negative correlation was found between the thresholds in both tasks and the Stroop interference test. Furthermore, in the first task, a positive correlation was found between thresholds and a trail making B test and a negative one with a total functional score. Conclusion Our data confirm that the impairment in time perception in persons affected by HD correlates with the advancing disease. They also suggest that time perception depends on similar cognitive mechanisms as the ones sub-serving the Stroop interference test.

The word glossolalia, also referred to as "speaking in tongues," originates from the Greek "glossa" which means "language" and "Lalia" which means "speak." It simply means to talk language. On a linguistic perspective, glossolalia is characterized by almost no recognizable words or semantic content, apart from biblical words and phrases, with an overrepresentation of a small phonemes number, accelerated speech output, and modification of accents and melody. Its phonemic properties have been said to resemble those of the language(s) of the speaker. It is generally a voluntary intimate communication act associated with religious spiritual thoughts, although it has also been described in mental disorders. Glossolalia state is a special mental state, completely different from aphasia. Aphasia is characterized by some phonological and grammatical rules; however, these are related to neurolinguistics and not to developmental principles. Unlike aphasia, glossolalia is not associated with central nervous system affection. There is, however, a psychiatric type of glossolalia, which, although similar in terms of phenomenology, is probably a different phenomenon. A common thought is that there is a linguistic trend, whose basic component is a stream of speech. This stream is suggested to use early-acquired rules of phonation, adapted according to socially meaningful values and attitudes, in an unconscious way. Therefore, the act of glossolalia is out of the "glossolalists" control. It would appear, therefore, that there is a broad spectrum of anomalous speech, of which religious glossolalia is only one manifestation. The aim of this chapter is to understand the mental state of glossolalia in comparison to aphasia in the light of neurolinguistic and psychiatric features. Moreover, we tried to highlight the underlying brain network. Pilot neuroscientific data suggest that it is associated with a deactivation of the cognitive system and an activation of some parts of the mirror neuron networks.

The word glossolalia, also referred to as "speaking in tongues," originates from the Greek "glossa" which means "language" and "Lalia" which means "speak." It simply means to talk language. On a linguistic perspective, glossolalia is characterized by almost no recognizable words or semantic content, apart from biblical words and phrases, with an overrepresentation of a small phonemes number, accelerated speech output, and modification of accents and melody. Its phonemic properties have been said to resemble those of the language(s) of the speaker. It is generally a voluntary intimate communication act associated with religious spiritual thoughts, although it has also been described in mental disorders. Glossolalia state is a special mental state, completely different from aphasia. Aphasia is characterized by some phonological and grammatical rules; however, these are related to neurolinguistics and not to developmental principles. Unlike aphasia, glossolalia is not associated with central nervous system affection. There is, however, a psychiatric type of glossolalia, which, although similar in terms of phenomenology, is probably a different phenomenon. A common thought is that there is a linguistic trend, whose basic component is a stream of speech. This stream is suggested to use early-acquired rules of phonation, adapted according to socially meaningful values and attitudes, in an unconscious way. Therefore, the act of glossolalia is out of the "glossolalists" control. It would appear, therefore, that there is a broad spectrum of anomalous speech, of which religious glossolalia is only one manifestation. The aim of this chapter is to understand the mental state of glossolalia in comparison to aphasia in the light of neurolinguistic and psychiatric features. Moreover, we tried to highlight the underlying brain network. Pilot neuroscientific data suggest that it is associated with a deactivation of the cognitive system and an activation of some parts of the mirror neuron networks.

Patients with supernumerary phantom limb report experiencing an additional limb duplicating its physical counterpart, usually following a stroke with sensorimotor disturbances. Here, we report a short‐lasting case of a right upper supernumerary phantom limb with unusual visuomotor features in a healthy participant during a pure Jacksonian motor seizure unexpectedly induced by continuous Theta‐Burst Stimulation over the left primary motor cortex. Electromyographic correlates of the event followed the phenomenological pattern of sudden appearance and brutal dissolution of the phantom, adding credit to the hypothesis that supernumerary phantom limb results from a dynamic resolution of conflictual multimodal information.

Notch signaling plays an instrumental role in hippocampus-dependent memory formation and recent evidence indicates a displacement of Notch1 and a reduction its activity in hippocampal and cortical neurons from Alzheimer's disease (AD) patients. As Notch activation depends on ligand availability, we investigated whether Jagged1 expression was altered in brain specimen of AD patients. We found that Jagged1 expression was reduced in the CA fields and that there was a gradual reduction of Jagged1 in the cerebrospinal fluid (CSF) with the progression of dementia. Given the role of Notch signaling in memory encoding, we investigated whether targeted loss of Jagged1 in neurons may be responsible for the memory loss seen in AD patients. Using a transgenic mouse model, we show that the targeted loss of Jagged1 expression during adulthood is sufficient to cause spatial memory loss and a reduction in exploration-dependent Notch activation. We also show that Jagged1 is selectively enriched at the presynaptic terminals in mice. Overall, the present data emphasizes the role of the Notch ligand, Jagged1, in memory formation and the potential deficit of the signaling ligand in AD patients.