• Aberrant resting-state oscillatory brain activity in Parkinson's disease patients with visual hallucinations: An MEG source-space study 

      Dauwan, Meenakshi; Hoff, Jorrit I; Vriens, Els M; Hillebrand, Arjan; Stam, Cornelis J; Sommer, Iris Else Clara (Peer reviewed; Journal article, 2019)
      To gain insight into possible underlying mechanism(s) of visual hallucinations (VH) in Parkinson's disease (PD), we explored changes in local oscillatory activity in different frequency bands with source-space magnetoenc ...
    • Auditory hallucinations, top-down processing and language perception: a general population study 

      de Boer, Janna N.; Linszen, Mascha M.J.; de Vries, J. Hans; Schutte, Maya J.L.; Begemann, Marieke J.H.; Heringa, Sophie M.; Bohlken, Marc Marijn; Hugdahl, Kenneth; Aleman, André; Wijnen, Frank N.K.; Sommer, Iris Else Clara (Peer reviewed; Journal article, 2019)
      Background: Studies investigating the underlying mechanisms of hallucinations in patients with schizophrenia suggest that an imbalance in top-down expectations v. bottom-up processing underlies these errors in perception. ...
    • Constructing the immune signature of schizophrenia for clinical use and research; an integrative review translating descriptives into diagnostics 

      Kroken, Rune Andreas; Sommer, Iris Else Clara; Steen, Vidar Martin; Dieset, Ingrid; Johnsen, Erik (Peer reviewed; Journal article, 2019)
      Schizophrenia is considered a syndrome comprised by several disease phenotypes, covering a range of underlying pathologies. One of these disease mechanisms seems to involve immune dysregulation and neuroinflammation. While ...
    • Efficacy of different types of cognitive enhancers for patients with schizophrenia: a meta-analysis 

      Sinkeviciute, Igne; Begemann, Marieke; Prikken, Merel; Oranje, Bob; Johnsen, Erik; Lei, Wan U.; Hugdahl, Kenneth; Kroken, Rune Andreas; Rau, Carina; Jacobs, Jolien D.; Mattaroccia, Silvia; Sommer, Iris Else Clara (Peer reviewed; Journal article, 2018)
      Cognitive impairment is a core feature of schizophrenia, which is predictive for functional outcomes and is, therefore, a treatment target in itself. Yet, literature on efficacy of different pharmaco-therapeutic options ...
    • Hallucinations in older adults: A practical review 

      Badcock, Johanna C.; Larøi, Frank; Kamp, Karina; Kelsall-Foreman, India; Bucks, Romola S.; Weinborn, Michael; Begemann, Marieke; Taylor, John-Paul; Collerton, Daniel; O'Brien, John T.; El Haj, Mohamad; Ffytche, Dominic; Sommer, Iris Else Clara (Journal article; Peer reviewed, 2020)
      By 2050, it is estimated that 16% of people will be aged above 65 years, compared with 9% in 2019.1 Population aging is driving increased attention to the physical and mental health needs of older adults. Here, our focus ...
    • Mapping psychotic-like experiences: Results from an online survey 

      Kusztrits, Isabella; Larøi, Frank; Laloyaux, Julien Freddy; Marquardt, Lynn Anne; Sinkeviciute, Igne; Kjelby, Eirik; Johnsen, Erik; Sommer, Iris Else Clara; Hugdahl, Kenneth; Hirnstein, Marco (Journal article; Peer reviewed, 2020-10-02)
      Suggestions have been made that psychotic‐like experiences (PLEs), such as hallucinatory and delusional experiences, exist on a continuum from healthy individuals to patients with a diagnosis of schizophrenia. We used the ...
    • Paracingulate sulcus morphology and hallucinations in clinical and nonclinical groups 

      Garrison, Jane R; Fernyhough, Charles; McCarthy-Jones, Simon; Simons, Jon S; Sommer, Iris Else Clara (Peer reviewed; Journal article, 2019)
      Hallucinations are a characteristic symptom of psychotic mental health conditions that are also experienced by many individuals without a clinical diagnosis. Hallucinations in schizophrenia have been linked to differences ...
    • Physical exercise improves quality of life, depressive symptoms, and cognition across chronic brain disorders: a transdiagnostic systematic review and meta-analysis of randomized controlled trials 

      Dauwan, Meenakshi; Begemann, Marieke J.H.; Slot, Margot I.E.; Lee, Edwin H.M.; Scheltens, Philip; Sommer, Iris Else Clara (Peer reviewed; Journal article, 2019)
      We performed a meta-analysis to synthesize evidence on the efficacy and safety of physical exercise as an add-on therapeutic intervention for quality of life (QoL), depressive symptoms and cognition across six chronic brain ...
    • The questionnaire for psychotic experiences: An examination of the validity and reliability 

      Rossell, Susan L.; Schutte, Maya J.L.; Toh, Wei Lin; Thomas, Neil; Strauss, Clara; Linszen, Mascha M.J.; van Dellen, Edwin; Heringa, Sophie M.; Teunisse, Rob; Slotema, Christina W.; Sommer, Iris Else Clara (Peer reviewed; Journal article, 2019-02-01)
      Psychotic experiences are prevalent across a wide variety of psychiatric, neurological, and medical conditions. Yet current assessments are often designed for one disorder, or are limited in their examination of phenomenological ...
    • Stratification and prediction of remission in first-episode psychosis patients: the OPTiMiSE cohort study 

      Martinuzzi, Emanuela; Barbosa, Susana; Daoudlarian, Douglas; Bel Haj Ali, Wafa; Gilet, Cyprien; Fillatre, Lionel; Khalfallah, Olfa; Troudet, Réjane; Jamain, Stéphane; Fond, Guillaume; Sommer, Iris Else Clara; Leucht, Stefan; Dazzan, Paola; McGuire, Philip; Arango, Celso; Diaz-Caneja, Covadonga M.; Fleischhacker, Wolfgang; Rujescu, Dan; Glenthøj, Birte; Winter, Inge; Kahn, René Sylvain; Yolken, Robert; Lewis, Shon; Drake, Richard; Davidovic, Laetitia; Leboyer, Marion; Glaichenhaus, Nicolas (Journal article; Peer reviewed, 2019)
      Early response to first-line antipsychotic treatments is strongly associated with positive long-term symptomatic and functional outcome in psychosis. Unfortunately, attempts to identify reliable predictors of treatment ...