Browsing by Author "Bora, E"

Now showing 1 - 2 of 2
  • No Thumbnail Available
    Item
    Executive dysfunction and cognitive subgroups in a large sample of euthymic patients with bipolar disorder
    (ELSEVIER SCIENCE BV) Bora, E; Hidiroglu, C; Özerdem, A; Kaçar, ÖF; Sarisoy, G; Arslan, FC; Aydemir, Ö; Tas, ZC; Vahip, S; Atalay, A; Atasoy, N; Atesci, F; Tümkaya, S
    Bipolar disorder (BP), at the group level, is associated with significant but modest cognitive deficits, including executive dysfunction. Among executive functions, response inhibition deficits have been suggested to be particularly relevant to BR However, BP is associated with significant heterogeneity in neurocognitive performance and level of functioning. Very few studies have investigated neurocognitive subgroups in BP with data-driven methods rather than arbitrarily defined criteria. Other than having relatively small sample sizes, previous studies have not taken into consideration the neurocognitive variability in healthy subjects. Five hundred-fifty-six euthymic patients with BP and 416 healthy controls were assessed using a battery of cognitive tests and clinical measures. Neurocognitive subgroups were investigated using latent class analysis, based on executive functions. Four neurocognitive subgroups, including a good performance cluster, two moderately low-performance groups, which differ in response inhibition and reasoning abilities, and a severe impairment cluster were found. In comparison to healthy controls, BP patients were overrepresented in severe impairment cluster (27% vs 5.3%) and underrepresented in good performance cluster. BP patients with lower educational attainment and older age were significantly more likely to be members of cognitively impaired subgroups. Antipsychotic use was less common in good performance cluster. These results suggest that there is a considerable overlap of cognitive functions between BP and healthy controls. Neurocognitive differences between BP and healthy controls are driven by a subgroup of patients who have severe and global, rather than selective, cognitive deficits. (C) 2016 Elsevier B.V. and ECNP. All rights reserved.
  • No Thumbnail Available
    Item
    Neuropsychological testing of cognitive impairment in euthymic bipolar disorder: an individual patient data meta-analysis
    (WILEY) Bourne, C; Aydemir, Ö; Balanzá-Martínez, V; Bora, E; Brissos, S; Cavanagh, JTO; Clark, L; Cubukcuoglu, Z; Dias, VV; Dittmann, S; Ferrier, IN; Fleck, DE; Frangou, S; Gallagher, P; Jones, L; Kieseppä, T; Martínez-Aran, A; Melle, I; Moore, PB; Mur, M; Pfennig, A; Raust, A; Senturk, V; Simonsen, C; Smith, DJ; Bio, DS; Soeiro-de-Souza, MG; Stoddart, SDR; Sundet, K; Szöke, A; Thompson, JM; Torrent, C; Zalla, T; Craddock, N; Andreassen, OA; Leboyer, M; Vieta, E; Bauer, M; Worhunsky, PD; Tzagarakis, C; Rogers, RD; Geddes, JR; Goodwin, GM
    Objective: An association between bipolar disorder and cognitive impairment has repeatedly been described, even for euthymic patients. Findings are inconsistent both across primary studies and previous meta-analyses. This study reanalysed 31 primary data sets as a single large sample (N = 2876) to provide a more definitive view. Method: Individual patient and control data were obtained from original authors for 11 measures from four common neuropsychological tests: California or Rey Verbal Learning Task (VLT), Trail Making Test (TMT), Digit Span and/or Wisconsin Card Sorting Task. Results: Impairments were found for all 11 test-measures in the bipolar group after controlling for age, IQ and gender (Ps <= 0.001, E.S. = 0.26-0.63). Residual mood symptoms confound this result but cannot account for the effect sizes found. Impairments also seem unrelated to drug treatment. Some test-measures were weakly correlated with illness severity measures suggesting that some impairments may track illness progression. Conclusion: This reanalysis supports VLT, Digit Span and TMT as robust measures of cognitive impairments in bipolar disorder patients. The heterogeneity of some test results explains previous differences in meta-analyses. Better controlling for confounds suggests deficits may be smaller than previously reported but should be tracked longitudinally across illness progression and treatment.