Hostname: page-component-76fb5796d-22dnz Total loading time: 0 Render date: 2024-04-27T00:18:44.126Z Has data issue: false hasContentIssue false

Planning performance in schizophrenia patients: a meta-analysis of the influence of task difficulty and clinical and sociodemographic variables

Published online by Cambridge University Press:  07 April 2017

F. Knapp*
Affiliation:
Kliniken Schmieder, Allensbach, Germany
W. Viechtbauer
Affiliation:
Department of Psychiatry and Neuropsychology, Maastricht University, Maastricht, The Netherlands
R. Leonhart
Affiliation:
Department of Psychology, University of Freiburg, Freiburg, Germany
K. Nitschke
Affiliation:
Department of Psychology, University of Freiburg, Freiburg, Germany Department of Neurology, Medical Center, University of Freiburg, Freiburg, Germany Medical Faculty, University of Freiburg, Freiburg, Germany Freiburg Brain Imaging Center, University of Freiburg, Freiburg, Germany BrainLinks-BrainTools Cluster of Excellence, University of Freiburg, Freiburg, Germany
C. P. Kaller*
Affiliation:
Department of Neurology, Medical Center, University of Freiburg, Freiburg, Germany Medical Faculty, University of Freiburg, Freiburg, Germany Freiburg Brain Imaging Center, University of Freiburg, Freiburg, Germany BrainLinks-BrainTools Cluster of Excellence, University of Freiburg, Freiburg, Germany
*
*Address for correspondence: F. Knapp and C. P. Kaller, Department of Neurology, University Medical Center Freiburg, Breisacher Str. 64, DE-79106 Freiburg, Germany. (Email: f.knapp@kliniken-schmieder.de) [F. K.] (Email: christoph.kaller@uniklinik-freiburg.de) [C. P. K.]
*Address for correspondence: F. Knapp and C. P. Kaller, Department of Neurology, University Medical Center Freiburg, Breisacher Str. 64, DE-79106 Freiburg, Germany. (Email: f.knapp@kliniken-schmieder.de) [F. K.] (Email: christoph.kaller@uniklinik-freiburg.de) [C. P. K.]

Abstract

Background

Despite a large body of research on planning performance in adult schizophrenia patients, results of individual studies are equivocal, suggesting either no, moderate or severe planning deficits. This meta-analysis therefore aimed to quantify planning deficits in schizophrenia and to examine potential sources of the heterogeneity seen in the literature.

Method

The meta-analysis comprised outcomes of planning accuracy of 1377 schizophrenia patients and 1477 healthy controls from 31 different studies which assessed planning performance using tower tasks such as the Tower of London, the Tower of Hanoi and the Stockings of Cambridge. A meta-regression analysis was applied to assess the influence of potential moderator variables (i.e. sociodemographic and clinical variables as well as task difficulty).

Results

The findings indeed demonstrated a planning deficit in schizophrenia patients (mean effect size: $\hat \mu \; = 0.67$; 95% confidence interval 0.56–0.78) that was moderated by task difficulty in terms of the minimum number of moves required for a solution. The results did not reveal any significant relationship between the extent of planning deficits and sociodemographic or clinical variables.

Conclusions

The current results provide first meta-analytic evidence for the commonly assumed impairments of planning performance in schizophrenia. Deficits are more likely to become manifest in problem items with higher demands on planning ahead, which may at least partly explain the heterogeneity of previous findings. As only a small fraction of studies reported coherent information on sample characteristics, future meta-analyses would benefit from more systematic reports on those variables.

Type
Original Articles
Copyright
Copyright © Cambridge University Press 2017 

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

Alvarez, JA, Emory, E (2006). Executive function and the frontal lobes: a meta-analytic review. Neuropsychology Review 16, 1742.Google Scholar
Andersen, R, Fagerlund, B, Rasmussen, H, Ebdrup, BH, Aggernaes, B, Gade, A, Oranje, B, Glenthoj, B (2013). The influence of impaired processing speed on cognition in first-episode antipsychotic-naïve schizophrenic patients. European Psychiatry: the Journal of the Association of European Psychiatrists 28, 332339.Google Scholar
Asevedo, E, Gadelha, A, Noto, C, Mansur, RB, Zugman, A, Belangero, SIN, Berberian, AA, Scarpato, BS, Leclerc, E, Teixeira, AL, Gama, CS, Bressan, RA, Brietzke, E (2013). Impact of peripheral levels of chemokines, BDNF and oxidative markers on cognition in individuals with schizophrenia. Journal of Psychiatric Research 47, 13761382.Google Scholar
Ayesa-Arriola, R, Rodriguez-Sanchez, JM, Gomez-Ruiz, E, Roiz-Santiáñez, R, Reeves, LL, Crespo-Facorro, B (2014). No sex differences in neuropsychological performance in first episode psychosis patients. Progress in Neuro-Psychopharmacology and Biological Psychiatry 48, 149154.Google Scholar
Badcock, JC, Michiel, PT, Rock, D (2005). Spatial working memory and planning ability: contrasts between schizophrenia and bipolar I disorder. Cortex 41, 753763.Google Scholar
Berg, K, Byrd, D (2002). The Tower of London spatial problem-solving task: enhancing clinical and research implementation. Journal of Clinical and Experimental Neuropsychology 24, 586604.Google Scholar
Berg, WK, Byrd, DL, McNamara, JPH, Case, K (2010). Deconstructing the tower: parameters and predictors of problem difficulty on the Tower of London task. Brain and Cognition 72, 472482.Google Scholar
Braw, Y, Benozio, A, Levkovitz, Y (2012). Executive functioning during full and partial remission (positive and negative symptomatic remission) of schizophrenia. Schizophrenia Research 142, 122128.Google Scholar
Braw, Y, Bloch, Y, Mendelovich, S, Ratzoni, G, Gal, G, Harari, H, Tripto, A, Levkovitz, Y (2008). Cognition in young schizophrenia outpatients: comparison of first-episode with multiepisode patients. Schizophrenia Bulletin 34, 544554.Google Scholar
Bustini, M, Stratta, P, Daneluzzo, E, Pollice, R, Prosperini, P, Rossi, A (1999). Tower of Hanoi and WCST performance in schizophrenia: problem-solving capacity and clinical correlates. Journal of Psychiatric Research 33, 285290.CrossRefGoogle Scholar
Carder, H, Handley, S, Perfect, T (2004). Deconstructing the Tower of London: alternative moves and conflict resolution as predictors of task performance. Quarterly Journal of Experimental Psychology 57, 14591483.Google Scholar
Culbertson, WC, Zillmer, EA (1998 a). The construct validity of the Tower of London DX as a measure of the executive functioning of ADHD children. Assessment 5, 215226.Google Scholar
Culbertson, WC, Zillmer, EA (1998 b). The Tower of LondonDX: a standardized approach to assessing executive functioning in children. Archives of Clinical Neuropsychology 13, 285301.Google Scholar
Debelak, R, Egle, J, Köstering, L, Kaller, CP (2016). Assessment of planning ability: psychometric analyses on the unidimensionality and construct validity of the Tower of London Task (TOL-F). Neuropsychology 30, 346360.Google Scholar
Diamond, A (2013). Executive functions. Annual Review of Psychology 64, 135168.Google Scholar
Dichter, GS, van der Stelt, O, Boch, JL, Belger, A (2006). Relations among intelligence, executive function, and P300 event related potentials in schizophrenia. Journal of Nervous and Mental Disease 194, 179187.Google Scholar
Dickinson, D, Ramsey, M, Gold, J (2007). Overlooking the obvious: a meta-analytic comparison of digit symbol coding tasks and other cognitive measures in schizophrenia. Archives of General Psychiatry 64, 532542.Google Scholar
Donohoe, G, Robertson, IH (2003). Can specific deficits in executive functioning explain the negative symptoms of schizophrenia? A review. Neurocase 9, 97108.Google Scholar
Elliott, R, McKenna, PJ, Robbins, TW, Sahakian, BI (1998). Specific neuropsychological deficits in schizophrenic patients with preserved intellectual function. Cognitive Neuropsychiatry 3, 4570.Google Scholar
Fagerlund, B, Mackeprang, T, Gade, A, Hemmingsen, R, Glenthøj, BY (2004). Low-dose Zuclopenthixol on cognitive functions in first-episode drug-naïve schizophrenia patients. CNS Spectrums 9, 364374.Google Scholar
Fatouros-Bergman, H, Cervenka, S, Flyckt, L, Edman, G, Farde, L (2014). Meta-analysis of cognitive performance in drug-naïve patients with schizophrenia. Schizophrenia Research 158, 156162.Google Scholar
Feldmann, D, Schuepbach, D, von Rickenbach, B, Theodoridou, A, Hell, D (2006). Association between two distinct executive tasks in schizophrenia: a functional transcranial Doppler sonography study. BMC Psychiatry 6, 25.Google Scholar
Fioravanti, M, Bianchi, V, Cinti, ME (2012). Cognitive deficits in schizophrenia: an updated metanalysis of the scientific evidence. BMC Psychiatry 12, 64.Google Scholar
Fioravanti, M, Carlone, O, Vitale, B, Cinti, ME, Clare, L (2005). A meta-analysis of cognitive deficits in adults with a diagnosis of schizophrenia. Neuropsychology Review 15, 7395.Google Scholar
Forbes, N, Carrick, L, McIntosh, A, Lawrie, S (2009). Working memory in schizophrenia: a meta-analysis. Psychological Medicine 39, 889905.Google Scholar
Goel, V (2002). Planning neural and psychological. In Encyclopedia of Cognitive Science (ed. Nadel, L), pp. 697703. Nature Publishing Group: London.Google Scholar
Goldberg, TE, Saint-Cyr, JA, Weinberger, R (1990). Assessment of procedural learning and problem solving in schizophrenic patients by Tower of Hanoi type tasks. Journal of Neuropsychiatry and Clinical Neurosciences 2, 165173.Google Scholar
Greenwood, KE, Wykes, T, Sigmundsson, T, Landau, S, Morris, RG (2011). Tower of London versus real life analogue planning in schizophrenia with disorganization and psychomotor poverty symptoms. Journal of the International Neuropsychological Society 17, 474484.Google Scholar
Hedges, L, Olkin, I (1985). Statistical Models for Meta-Analysis. Academic Press: New York.Google Scholar
Heinrichs, RW, Zakzanis, KK (1998). Neurocognitive deficit in schizophrenia: a quantitative review of the evidence. Neuropsychology 12, 426445.Google Scholar
Higgins, JPT, Thompson, SG (2004). Controlling the risk of spurious findings from meta-regression. Statistics in Medicine 23, 16631682.Google Scholar
Hilti, CC, Delko, T, Orosz, AT, Thomann, K, Ludewig, S, Geyer, MA, Vollenweider, FX, Feldon, J, Cattapan-Ludewig, K (2010). Sustained attention and planning deficits but intact attentional set-shifting in neuroleptic-naïve first-episode schizophrenia patients. Neuropsychobiology 61, 7986.Google Scholar
Holt, DV, Wolf, J, Funke, J, Weisbrod, M, Kaiser, S (2013). Planning impairments in schizophrenia: specificity, task independence and functional relevance. Schizophrenia Research 149, 174179.Google Scholar
Huddy, VC, Hodgson, TL, Kapasi, M, Mutsatsa, SH, Harrison, I, Barnes, TRE, Joyce, EM (2007). Gaze strategies during planning in first-episode psychosis. Journal of Abnormal Psychology 116, 589598.Google Scholar
Humes, GE, Welsh, MC, Retzlaff, P, Cookson, N (1997). Towers of Hanoi and London: reliability and validity of two executive function tasks. Assessment 4, 249257.Google Scholar
Joyce, E, Hutton, S, Mutsatsa, S, Gibbins, H, Webb, E, Paul, S, Robbins, T, Barnes, T (2002). Executive dysfunction in first-episode schizophrenia and relationship to duration of untreated psychosis: the West London Study. British Journal of Psychiatry 181, 3844.Google Scholar
Jurado, M, Rosselli, M (2007). The elusive nature of executive functions: a review of our current understanding. Neuropsychology Review 17, 213233.Google Scholar
Kafer, KL, Hunter, M (1997). On testing the face validity of planning/problem-solving tasks in a normal population. Journal of the International Neuropsychological Society: JINS 3, 108119.Google Scholar
Kaller, CP, Debelak, R, Köstering, L, Egle, J, Rahm, B, Wild, PS, Blettner, M, Beutel, ME, Unterrainer, JM (2016). Assessing planning ability across the adult life span: population-representative and age-adjusted reliability estimates for the Tower of London (TOL-F). Archives of Clinical Neuropsychology 31, 148164.Google Scholar
Kaller, CP, Rahm, B, Köstering, L, Unterrainer, JM (2011 a). Reviewing the impact of problem structure on planning: a software tool for analyzing tower tasks. Behavioural Brain Research 216, 18.Google Scholar
Kaller, CP, Rahm, B, Spreer, J, Mader, I, Unterrainer, JM (2008). Thinking around the corner: the development of planning abilities. Brain and Cognition 67, 360370.Google Scholar
Kaller, CP, Rahm, B, Spreer, J, Weiller, C, Unterrainer, JM (2011 b). Dissociable contributions of left and right dorsolateral prefrontal cortex in planning. Cerebral Cortex 21, 307317.Google Scholar
Kaller, CP, Unterrainer, JM, Rahm, B, Halsband, U (2004). The impact of problem structure on planning: insights from the Tower of London task. Cognitive Brain Research 20, 462472.Google Scholar
Kaller, CP, Unterrainer, JM, Stahl, C (2012). Assessing planning ability with the Tower of London task: psychometric properties of a structurally balanced problem set. Psychological Assessment 24, 4653.Google Scholar
Kay, SR, Opler, LA, Lindenmayer, JP (1989). The Positive and Negative Syndrome Scale (PANSS): rationale and standardisation. British Journal of Psychiatry. Supplement, issue 7, 5967.Google Scholar
Knowles, E, David, A, Reichenberg, A (2010). Processing speed deficits in schizophrenia: reexamining the evidence. American Journal of Psychiatry 167, 828835.Google Scholar
Konstantopoulos, S (2011). Fixed effects and variance components estimation in three-level meta-analysis. Research Synthesis Methods 2, 6176.Google Scholar
Kontis, D, Theochari, E, Fryssira, H, Kleisas, S, Sofocleous, C, Andreopoulou, A, Kalogerakou, S, Gazi, A, Boniatsi, L, Chaidemenos, A, Tsaltas, E (2013). COMT and MTHFR polymorphisms interaction on cognition in schizophrenia: an exploratory study. Neuroscience Letters 537, 1722.Google Scholar
Köstering, L, McKinlay, A, Stahl, C, Kaller, CP (2012). Differential patterns of planning impairments in Parkinson's disease and sub-clinical signs of dementia? A latent-class model-based approach. PLOS ONE 7, e38855.CrossRefGoogle ScholarPubMed
Köstering, L, Nitschke, K, Schumacher, FK, Weiller, C, Kaller, CP (2015 a). Test–retest reliability of the Tower of London planning task (TOL-F). Psychological Assessment 27, 925931.Google Scholar
Köstering, L, Schmidt, CSM, Egger, K, Amtage, F, Peter, J, Klöppel, S, Beume, L-A, Hoeren, M, Weiller, C, Kaller, CP (2015 b). Assessment of planning performance in clinical samples: reliability and validity of the Tower of London task (TOL-F). Neuropsychologia 75, 646655.Google Scholar
Köstering, L, Stahl, C, Leonhart, R, Weiller, C, Kaller, CP (2014). Development of planning abilities in normal aging: differential effects of specific cognitive demands. Developmental Psychology 50, 293303.Google Scholar
Krabbendam, L, de Vugt, ME, Derix, MM, Jolles, J (1999). The behavioural assessment of the dysexecutive syndrome as a tool to assess executive functions in schizophrenia. Clinical Neuropsychologist 13, 370375.Google Scholar
Langdon, R, Coltheart, M, Ward, PB, Catts, SV (2001). Mentalising, executive planning and disengagement in schizophrenia. Cognitive Neuropsychiatry 6, 81108.Google Scholar
Langdon, R, Coltheart, M, Ward, PB, Catts, SV (2002). Disturbed communication in schizophrenia: the role of poor pragmatics and poor mind-reading. Psychological Medicine 32, 12731284.Google Scholar
Lezak, MD, Howieson, DB, Loring, DW (2004). Neuropsychological Assessment. Oxford University Press: New York.Google Scholar
Lowe, C, Rabbitt, P (1998). Test/re-test reliability of the CANTAB and ISPOCD neuropsychological batteries: theoretical and practical issues. Cambridge Neuropsychological Test Automated Battery. International study of post-operative cognitive dysfunction. Neuropsychologia 36, 915923.Google Scholar
Marczewski, P, de Linden, MV, Larøi, F (2001). Further investigation of the supervisory attentional system in schizophrenia: planning, inhibition, and rule abstraction. Cognitive Neuropsychiatry 6, 175192.Google Scholar
McCormack, T, Atance, CM (2011). Planning in young children: a review and synthesis. Developmental Review 31, 131.Google Scholar
McKinlay, A, Kaller, CP, Grace, RC, Dalrymple-Alford, JC, Anderson, TJ, Fink, J, Roger, D (2008). Planning in Parkinson's disease: a matter of problem structure? Neuropsychologia 46, 384389.Google Scholar
Mesholam-Gately, RI, Giuliano, AJ, Goff, KP, Faraone, SV, Seidman, LJ (2009). Neurocognition in first-episode schizophrenia: a meta-analytic review. Neuropsychology 23, 315336.Google Scholar
Minzenberg, MJ, Laird, AR, Thelen, S, Carter, CS, Glahn, DC (2009). Meta-analysis of 41 functional neuroimaging studies of executive function in schizophrenia. Archives of General Psychiatry 66, 811822.Google Scholar
Miyake, A, Friedman, N, Emerson, M, Witzki, A, Howerter, A, Wager, T (2000). The unity and diversity of executive functions and their contributions to complex “Frontal Lobe” tasks: a latent variable analysis. Cognitive Psychology 41, 49100.Google Scholar
Moher, D, Liberati, A, Tetzlaff, J, Altman, DG; PRISMA Group (2009). Preferred Reporting Items for Systematic Reviews and Meta-Analyses: The PRISMA Statement. PLoS Medicine 6, e1000097.Google Scholar
Morice, R, Delahunty, A (1996). Frontal/executive impairments in schizophrenia. Schizophrenia Bulletin 22, 125137.Google Scholar
Morris, RG, Rushe, T, Woodruffe, PWR, Murray, RM (1995). Problem solving in schizophrenia: a specific deficit in planning ability. Schizophrenia Research 14, 235246.Google Scholar
Newman, SD, Greco, JA, Lee, D (2009). An fMRI study of the Tower of London: a look at problem structure differences. Brain Research 1286, 123132.Google Scholar
Newman, SD, Pittman, G (2007). The Tower of London: a study of the effect of problem structure on planning. Journal of Clinical and Experimental Neuropsychology 29, 333342.Google Scholar
Nitschke, K, Köstering, L, Finkel, L, Weiller, C, Kaller, CP (2017). A meta-analysis on the neural basis of planning: activation likelihood estimation of functional brain imaging results in the Tower of London task. Human Brain Mapping 38, 396413.Google Scholar
Nitschke, K, Ruh, N, Kappler, S, Stahl, C, Kaller, CP (2012). Dissociable stages of problem solving (I): temporal characteristics revealed by eye-movement analyses. Brain and Cognition 80, 160169.Google Scholar
Norman, D, Shallice, T (1986). Attention to action: willed and automatic control of behavior. In Consciousness and Self-Regulation: Advances in Research and Theory (ed. Davidson, R, Schwartz, G and Shapiro, D), pp. 118. Plenum: New York.Google Scholar
Okruszek, Ł, Rutkowska, A (2013). Planning disorders in men with schizophrenia and in men with localized frontal lobe lesions. [Article in Polish] Psychiatria Polska 47, 921931.Google Scholar
Owen, A (2005). Cognitive planning in humans: new insights from the Tower of London (TOL) task. In The Cognitive Psychology of Planning (ed. Morris, R and Ward, G), pp. 135151. Psychology Press: Hove.Google Scholar
Palmer, B, Dawes, S, Heaton, R (2009). What do we know about neuropsychological aspects of schizophrenia? Neuropsychology Review 19, 365384.Google Scholar
Pantelis, C, Barnes, TRE, Nelson, HE, Tanner, S, Weatherley, L, Owen, AM, Robbins, TW (1997). Frontal–striatal cognitive deficits in patients with chronic schizophrenia. Brain 120, 18231843.Google Scholar
R Core Team (2015). R: A Language and Environment for Statistical Computing (version 3.2.3) (http://www.R-project.org).Google Scholar
Rainville, C, Lepage, E, Gauthier, S, Kergoat, M-J, Belleville, S (2012). Executive function deficits in persons with mild cognitive impairment: a study with a Tower of London task. Journal of Clinical and Experimental Neuropsychology 34, 306324.Google Scholar
Rohatgi, A (2015). WebPlotDigitizer (version 3.9) (http://arohatgi.info/WebPlotDigitizer).Google Scholar
Ruh, N, Rahm, B, Unterrainer, JM, Weiller, C, Kaller, CP (2012). Dissociable stages of problem solving (II): first evidence for process-contingent temporal order of activation in dorsolateral prefrontal cortex. Brain and Cognition 80, 170176.CrossRefGoogle ScholarPubMed
Saleem, MM, Harte, MK, Marshall, KM, Scally, A, Brewin, A, Neill, JC (2013). First episode psychosis patients show impaired cognitive function – a study of a South Asian population in the UK. Journal of Psychopharmacology 27, 366373.Google Scholar
Schaefer, J, Giangrande, E, Weinberger, D, Dickinson, D (2013). The global cognitive impairment in schizophrenia: consistent over decades and around the world. Schizophrenia Research 150, 4250.Google Scholar
Schnirman, GM, Welsh, MC, Retzlaff, PD (1998). Development of the Tower of London-Revised. Assessment 5, 355360.Google Scholar
Shum, D, Ungvari, GS, Tang, W-K, Leung, JP (2004). Performance of schizophrenia patients on time-, event-, and activity-based prospective memory tasks. Schizophrenia Bulletin 30, 693701.Google Scholar
Stanley, TD, Doucouliagos, H (2014). Meta-regression approximations to reduce publication selection bias. Research Synthesis Methods 5, 6078.Google Scholar
Sullivan, J, Riccio, C, Castillo, C (2009). Concurrent validity of the tower tasks as measures of executive function in adults: a meta-analysis. Applied Neuropsychology 16, 6275.Google Scholar
Syväoja, HJ, Tammelin, TH, Ahonen, T, Räsänen, P, Tolvanen, A, Kankaanpää, A, Kantomaa, MT (2015). Internal consistency and stability of the CANTAB neuropsychological test battery in children. Psychological Assessment 27, 698709.Google Scholar
Tenjin, T, Miyamoto, S, Miyake, N, Ogino, S, Kitajima, R, Ojima, K, Arai, J, Teramoto, H, Tsukahara, S, Ito, Y, Tadokoro, M, Anai, K, Funamoto, Y, Kaneda, Y, Sumiyoshi, T, Yamaguchi, N (2012). Effect of blonanserin on cognitive function in antipsychotic-naïve first-episode schizophrenia. Human Psychopharmacology 27, 90100.Google Scholar
Thompson, S, Higgins, J (2002). How should meta-regression analyses be undertaken and interpreted? Statistics in Medicine 21, 15591573.Google Scholar
Tsuchimine, S, Yasui-Furukori, N, Kaneda, A, Kaneko, S (2013). Differential effects of the catechol-O-methyltransferase Val158Met genotype on the cognitive function of schizophrenia patients and healthy Japanese individuals. PLOS ONE 8, e76763.Google Scholar
Tunstall, JR, O'Gorman, JG, Shum, DHK (2016). A four-disc version of the Tower of London for clinical use. Journal of Neuropsychology 10, 116129.Google Scholar
Tyson, PJ, Laws, KR, Roberts, KH, Mortimer, AM (2004). Stability of set-shifting and planning abilities in patients with schizophrenia. Psychiatry Research 129, 229239.Google Scholar
Unterrainer, JM, Kaller, CP, Loosli, SV, Heinze, K, Ruh, N, Paschke-Müller, M, Rauh, R, Biscaldi, M, Rahm, B (2015 a). Looking ahead from age 6 to 13: a deeper insight into the development of planning ability. British Journal of Psychology 106, 4667.Google Scholar
Unterrainer, JM, Owen, AM (2006). Planning and problem solving: from neuropsychology to functional neuroimaging. Journal of Physiology, Paris 99, 308317.Google Scholar
Unterrainer, JM, Rahm, B, Halsband, U, Kaller, CP (2005). What is in a name: comparing the Tower of London with one of its variants. Cognitive Brain Research 23, 418428.Google Scholar
Unterrainer, JM, Rauh, R, Rahm, B, Hardt, J, Kaller, CP, Klein, C, Paschke-Müller, M, Biscaldi, M (2015 b). Development of planning in children with high-functioning autism spectrum disorders and/or attention deficit/hyperactivity disorder. Autism Research 9, 739751.Google Scholar
Unterrainer, JM, Ruh, N, Loosli, SV, Heinze, K, Rahm, B, Kaller, CP (2013). Planning steps forward in development: in girls earlier than in boys. PLOS ONE 8, e80772.Google Scholar
van Houwelingen, H, Arends, L, Stijnen, T (2002). Advanced methods in meta-analysis: multivariate approach and meta-regression. Statistics in Medicine 21, 589624.Google Scholar
Ventura, J, Hellemann, GS, Thames, AD, Koellner, V, Nuechterlein, KH (2009). Symptoms as mediators of the relationship between neurocognition and functional outcome in schizophrenia: a meta-analysis. Schizophrenia Research 113, 189199.Google Scholar
Viechtbauer, W (2010). Conducting meta-analyses in R with the metafor package. Journal of Statistical Software 36, 148.Google Scholar
Ward, G, Allport, A (1997). Planning and problem-solving using the five-disc Tower of London task. Quarterly Journal of Experimental Psychology 50, 4978.Google Scholar
Ward, G, Morris, R (2005). Introduction to the psychology of planning. In The Cognitive Psychology of Planning (ed. Ward, G and Morris, R), pp. 134. Psychology Press: Hove.Google Scholar
Zhu, Y, Liu, X, Wang, H, Jiang, T, Fang, Y, Hu, H, Wang, G, Wang, X, Liu, Z, Zhang, K (2010). Reduced prefrontal activation during Tower of London in first-episode schizophrenia: a multi-channel near-infrared spectroscopy study. Neuroscience Letters 478, 136140.Google Scholar
Supplementary material: PDF

Knapp supplementary material

Knapp supplementary material 1

Download Knapp supplementary material(PDF)
PDF 310.9 KB