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Yayın The cerebral blood flow deficits in Parkinson’s disease with mild cognitive impairment using arterial spin labeling MRI(Springer, 2020-09) Arslan, Dilek Betül; Gürvit, İbrahim Hakan; Genç, Ozan; Kıçik, Ani; Eryürek, Kardelen; Cengiz, Sevim; Erdoğdu, Emel; Yıldırım, Zerrin; Tüfekçioğlu, Zeynep; Uluğ, Aziz Müfit; Bilgiç, Başar; Hanağası, Haşmet Ayhan; Tüzün, Erdem; Demiralp, Tamer; Öztürk Işık, EsinParkinson's disease (PD) with mild cognitive impairment (PD-MCI) is currently diagnosed based on an arbitrarily predefined standard deviation of neuropsychological test scores, and more objective biomarkers for PD-MCI diagnosis are needed. The purpose of this study was to define possible brain perfusion-based biomarkers of not only mild cognitive impairment, but also risky gene carriers in PD using arterial spin labeling magnetic resonance imaging (ASL-MRI). Fifteen healthy controls (HC), 26 cognitively normal PD (PD-CN), and 27 PD-MCI subjects participated in this study. ASL-MRI data were acquired by signal targeting with alternating radio-frequency labeling with Look-Locker sequence at 3 T. Single nucleotide polymorphism genotyping for rs9468 [microtubule-associated protein tau (MAPT) H1/H1 versus H1/H2 haplotype] was performed using a Stratagene Mx3005p real-time polymerase chain-reaction system (Agilent Technologies, USA). There were 15 subjects withMAPTH1/H1 and 11 subjects withMAPTH1/H2 within PD-MCI, and 33 subjects withMAPTH1/H1 and 19 subjects withMAPTH1/H2 within all PD. Voxel-wise differences of cerebral blood flow (CBF) values between HC, PD-CN and PD-MCI were assessed by one-way analysis of variance followed by pairwise post hoc comparisons. Further, the subgroup of PD patients carrying the riskyMAPTH1/H1 haplotype was compared with noncarriers (MAPTH1/H2 haplotype) in terms of CBF by a two-samplettest. A pattern that could be summarized as "posterior hypoperfusion" (PH) differentiated the PD-MCI group from the HC group with an accuracy of 92.6% (sensitivity = 93%, specificity = 93%). Additionally, the PD patients withMAPTH1/H1 haplotype had decreased perfusion than the ones with H1/H2 haplotype at the posterior areas of the visual network (VN), default mode network (DMN), and dorsal attention network (DAN). The PH-type pattern in ASL-MRI could be employed as a biomarker of both current cognitive impairment and future cognitive decline in PD.Yayın An investigation of affective theory of mind ability and its relation to neuropsychological functions in Alzheimer's disease(John Wiley and Sons Ltd., 2020-09) Yıldırım, Elif; Soncu Büyükişcan, Ezgi; Demirtaş Tatlıdede, Aslı; Bilgiç, Başar; Gürvit, İbrahim HakanAlthough cognitive theory of mind (ToM) has been largely studied within neurodegenerative disorders including Alzheimer's disease (AD), studies focusing on affective ToM are relatively limited, yielding inconsistent findings. The current study aimed at investigating affective ToM abilities within different stages of AD (mild AD dementia [ADD], mild cognitive impairment [MCI], and subjective cognitive impairment [SCI]), together with its relationship with neuropsychological functioning. Eighty-one participants were tested with two different ToM tasks (Faux Pas Recognition Test [FPR] and Reading Mind in the Eyes Test [RMET]) and tests of attention, executive functions, episodic memory, and facial recognition. Our results showed two different affective ToM profiles in AD continuum: while ADD group performed poorly on both tasks of ToM, MCI group displayed deteriorated performance on RMET but not on FPR. In addition, ToM performance was significantly related to episodic memory and verbal fluency within the overall sample. These findings suggest that impairment in the decoding process of emotional cues could begin even in the prodromal stage of AD. In contrast, the reasoning process of emotional information, as measured with FPR, could be preserved until the dementia stage. Moreover, the relation of affective ToM with amnestic functions and verbal abilities could provide evidence of a domain-general ToM impairment in AD.Yayın Detection of visual and frontoparietal network perfusion deficits in Parkinson's disease dementia(Elsevier Ireland Ltd, 2021-11) Azamat, Sena; Arslan, Dilek Betül; Erdoğdu, Emel; Kıçik, Ani; Cengiz, Sevim; Eryürek, Kardelen; Tüfekçioğlu, Zeynep; Bilgiç, Başar; Hanagasi, Haşmet; Demiralp, Tamer; Gürvit, Hakan; Öztürk Işık, EsinMild cognitive impairment of Parkinson's disease (PD) may be an early manifestation that may progressively worsen to dementia. Cognitive decline has been associated with changes in the brain perfusion pattern. This study aimed to evaluate cerebral blood flow (CBF) deficits specific to different stages of cognitive decline. Seventeen patients with cognitively normal PD (PD-CN), 18 patients with PD with mild cognitive impairment (PD-MCI), and 16 patients with PD with dementia (PDD) were included in this study. The participants were scanned using a 3 T Philips MRI scanner. Arterial spin labelling magnetic resonance (ASL-MR) images were acquired, followed by calculation of the CBF maps, and registration onto the MNI152 brain atlas. A whole-brain voxel-based CBF comparison was performed among the patient groups using age as a covariate. The mean age of patients with PDD was significantly higher than that of patients with PD-MCI (P = 0.015) and PD-CN (P = 0.001). The CBF values of the three groups were significantly different in the left cuneus of the visual network (VN), left inferior frontal gyrus of the frontoparietal network (FPN), and left dorsomedial nucleus of the thalamus. PDD had lower perfusion values than PD-MCI group in the same regions detected in the main group analysis. Additionally, comparison of PDD with PD-CN and non-demented groups revealed that the perfusion reduction extended into the bilateral cuneus of the VN, bilateral thalami, and left inferior frontal gyrus of the FPN. PDD could be separated from PD-MCI and PD-CN stages with CBF deficits in non-dopaminergically mediated posterior and dopaminergically mediated frontal networks.Yayın An investigation of affective personality traits in Alzheimer’s disease: seeking as a possible predictor for early-stage Alzheimer’s dementia(Routledge, 2023-09) Soncu Büyükişcan, Ezgi; Yıldırım, Elif; Demirtaş Tatlıdede, Aslı; Bilgiç, Başar; Gürvit, HakanObjective: The aim of the current study was to investigate affective personality traits in Alzheimer’s disease, a neurodegenerative condition mainly characterized by episodic memory impairment. Method: The sample included 69 participants from 3 diagnostic categories. Twenty-five participants were diagnosed with subjective cognitive impairment (SCI), 26 participants were diagnosed with mild cognitive impairment of the amnestic type (aMCI), and the remaining 18 participants were diagnosed with early-stage Alzheimer’s dementia (ADD). Diagnostic labels were given as a result of detailed neurological, neuropsychological, and neuroradiological assessment. Affective personality traits were assessed via Affective Neuroscience Personality Scales (ANPS). Results: The only significant intergroup difference was obtained for the SEEKING subscale of ANPS. Here, ADD group scored significantly lower compared to the SCI group. The results of logistic regression analysis also indicated that SEEKING score successfully predicted early-stage ADD diagnosis. Conclusion: The results suggest that a specific personality constellation characterized by reduced investment in the outside world might be associated with Alzheimer’s disease, either as a risk factor or a byproduct of the neurodegenerative process initiated by AD pathology.Yayın Alzheimer hastalığında olağan durum ağı bağlantısallığı(Türkiye Sinir Ve Ruh Sağlığı Derneği, 2019-12) Yıldırım, Elif; Soncu Büyükişcan, EzgiAmaç: Alzheimer hastalığı (AH) beyinde yapısal ve işlevsel değişimler meydana getiren nörodejeneratif bir hastalıktır. Gelişen beyin görüntüleme yöntemleri sayesinde AH patolojisine eşlik eden yapısal ve işlevsel bağlantılardaki bozulmalar gitgide daha görünür hale gelmiştir. AH’de dinlenim durumu bağlantısallığında, özellikle de olağan durum ağı (default mode network - DMN) olarak adlandırılan içsel bağlantısallık ağında farklılaşmalar görülmektedir. Bu çalışmada DMN bağlantısallık bulgularının incelenmesi ve tartışılması amaçlanmıştır. Yöntem: İşlevsel manyetik rezonans görüntüleme (fMRI) çalışmalarında en yaygın kullanılan 2 temel metodoloji (tohum temelli ve bağımsız bileşen analizi) temel alınarak alanda yapılan çalışmalar incelenmiştir. Bulgular: Çalışmalar genel olarak, DMN bağlantısallığının AH süreci boyunca ilerleyici bir şekilde bozulduğunu göstermektedir. DMN alt sistemlerinin AH’nin preklinik ve prodromal evrelerinde farklı bağlantısallık örüntüleri gösterdiği de belirtilmektedir. DMN’deki bozulmanın diğer bağlantısallık ağlarındaki farklılaşma ile ilişkili olabileceğini öne süren kanıtlar da mevcuttur. Buna ek olarak, bulgular DMN’nin AH ile ilişkili nöropatoloji ve genetik risk faktörleri ile olan ilişkisine de işaret etmektedir. Sonuç: AH’nin beyinde başta DMN olmak üzere diğer dinlenim durumu ağlarında işlevsel bozulmalara yol açan yaygın bir diskonneksiyon sendromu olduğu öne sürülebilir. Buna ek olarak, preklinik vakalarda ve risk taşıyan kişilerde de saptanabilen AH ile ilişkili işlevsel bağlantısallık değişimleri AH için muhtemel bir biyo-belirteç olabilir.Yayın White-matter changes in early and late stages of mild cognitive impairment(Churchill Livingstone, 2020-08) Femir Gürtuna, Banu; Kurt, Elif; Ulaşoğlu Yıldız, Çiğdem; Bayram, Ali; Yıldırım, Elif; Soncu Büyükişcan, Ezgi; Bilgiç, BaşarMild Cognitive Impairment (MCI) is characterized by cognitive deficits that exceed age-related decline, but not interfering with daily living activities. Amnestic type of the disorder (aMCI) is known to have a high risk to progress to Alzheimer's Disease (AD), the most common type of dementia. Identification of very early structural changes in the brain related to the cognitive decline in MCI patients would further contribute to the understanding of the dementias. In the current study, we target to investigate whether the white-matter changes are related to structural changes, as well as the cognitive performance of MCI patients. Forty-nine MCI patients were classified as Early MCI (E-MCI, n = 24) and Late MCI (L-MCI, n = 25) due to their performance on The Free and Cued Selective Reminding Test (FCSRT). Age-Related White-Matter Changes (ARWMC) scale was used to evaluate the white-matter changes in the brain. Volumes of specific brain regions were calculated with the FreeSurfer program. Both group and correlation analyses were conducted to show if there was any association between white-matter hyperintensities (WMHs) and structural changes and cognitive performance. Our results indicate that, L-MCI patients had significantly more WMHs not in all but only in the frontal regions compared to E-MCI patients. Besides, ARWMC scores were not correlated with total hippocampal and white-matter volumes. It can be concluded that WMHs play an important role in MCI and cognitive functions are affected by white-matter changes of MCI patients, especially in the frontal regions.Yayın Investigation of symptom-specific functional connectivity patterns in Parkinson’s disease(Springer-Verlag Italia S.R.L., 2025-06-14) Kıçik, Ani; Bayram, Ali; Erdoğdu, Emel; Kurt, Elif; Sarıdede, Dilek Betül; Cengiz, Sevim; Bilgiç, Başar; Hanağası, Haşmet; Öztürk Işık, Esin; Gürvit, Hakan; Tüzün, Erdem; Demiralp, TamerParkinson’s disease (PD) is a complex neurodegenerative disease, characterized by pronounced heterogeneity in symptoms. This study investigates the functional connectivity (FC) patterns associated with distinct symptom clusters, aiming to elucidate the heterogeneity in PD and uncover the neural mechanisms underlying its motor and cognitive symptoms. Resting-state functional MRI (rs-fMRI) data from 55 non-demented PD patients and 24 healthy controls (HC) were used to perform seed-to-seed FC analyses. A clustering algorithm was applied to the cognitive and motor scores of all PD patients to generate relatively homogeneous symptomatic subgroups. PD patients exhibited a general decrease in FC within a network comprising the sensorimotor network (SMN) and the visual network (VN) regions. Symptom-based clustering revealed three relatively homogeneous subgroups, exhibiting a gradient pattern: patients with greater motor deficits showed significant disconnection within the SMN, whereas patients with greater visuospatial deficits exhibited reduced FC in an extended subnetwork, with pronounced disconnections between the VN and SMN areas. Our study demonstrated a notable disconnection between the SMN and VN, indicating impaired visual-motor integration in PD. Stronger disconnection within the SMN was associated with greater motor dysfunction, and stronger visual-sensorimotor disconnections were associated with greater visuospatial deficits. These findings suggest that at least two separate routes of functional disconnection may be responsible for the inhomogeneous symptom distribution in PD.Yayın Reliability of direct-to-home teleneuropsychological assessment: a within-subject design study(Routledge, 2025-07-04) Yıldırım, Elif; Soncu Büyükişcan, Ezgi; Akça Kalem, Şükriye; Gürvit, HakanObjective: During the COVID-19 pandemic, the need to continue diagnosis and treatment processes, in addition to scientific research, led to a rapid shift towards direct-to-home tele-neuropsychology administrations, the reliability and validity of which had not been clearly established then. This study, therefore, aimed to examine the reliability of direct-to-home tele-neuropsychological assessment (TNP). Method: The sample included 105 cognitively healthy individuals aged between 50–83 years, and 47 patients diagnosed with neurocognitive disorders (mild cognitive impairment and early-stage Alzheimer’s type dementia). All participants underwent both face-to-face and teleneuropsychological assessments in a counterbalanced order. Results: The results revealed that performances across measures of attention, working memory, verbal fluency, verbal and visual memory, and visual perception were comparable across assessment modalities. Intraclass correlation coefficients of the tests ranged from.54 to.92. Conclusions: The findings of the study provide support for direct-to-home teleneuropsychological assessment among patients with neurocognitive disorders. Neuropsychological tests relying on verbal administration and independent of motor performance may represent a reliable alternative for this patient group when administered in settings where external distractions or technological limitations are controlled. For cognitively healthy individuals, on the other hand, the reliability of the TNP application is more questionable for memory and some executive function tests and therefore needs further exploration.
