UvA-DARE (Digital Academic Repository) A shrunken world - micropsia after a right occipito-parietal ischemic stroke Van Den Berg, N.S.; Huitema, R.B.; Spikman, J.M.; Van Laar, P.J.; De Haan, E.H.F. DOI 10.1080/13554794.2019.1656751 Publication date 2019 Document Version Final published version Published in Neurocase License CC BY-NC-ND Link to publication Citation for published version (APA): Van Den Berg, N. S., Huitema, R. B., Spikman, J. M., Van Laar, P. J., & De Haan, E. H. F. (2019). A shrunken world - micropsia after a right occipito-parietal ischemic stroke. Neurocase, 25(5), 202-208. https://doi.org/10.1080/13554794.2019.1656751 General rights It is not permitted to download or to forward/distribute the text or part of it without the consent of the author(s) and/or copyright holder(s), other than for strictly personal, individual use, unless the work is under an open content license (like Creative Commons). 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Van Den Berg a,b,RientsB.Huitema b,JacobaM.Spikman b, Peter Jan Van Laar c andEdwardH.F.DeHaan a aDepartment of Brain and Cognition, University of Amsterdam, Amsterdam, The Netherlands; bDepartment of Neurology, University Medical Center Groningen, Groningen, The Netherlands; cDepartment of Radiology, University Medical Center Groningen, Groningen, The Netherlands ABSTRACT ARTICLE HISTORY Micropsia is a rare condition in which patients perceive the outside world smaller in size than it actually Received 3 June 2019 is. We examined a patient who, after a right occipito-parietal stroke, subjectively reported perceiving Accepted 11 August 2019 fi everything at seventy percent of the actual size. Using experimental tasks, we con rmed the extent of KEYWORDS fi his micropsia at 70%. Visual half- eld tests showed an impaired perception of shape, location and Micropsia; metamorphopsia; motion in the left visual field. As his micropsia concerns the complete visual field, we suggest that it is visual perceptual caused by a higher-order compensation process in order to reconcile the conflicting information from impairment; the two hemifields. occipito-parietal infarction; neuropsychology Introduction There is still controversy about the theories explaining micro- psia. It has been put forward that micropsia is caused by A distorted perception of the outside world, also referred to as a disturbance in the underlying mechanism responsible for size- metamorphopsia, is one of the intriguing visual disorders that may constancy (Bender & Teuber, 1947; Kassubek et al., 1999). The occur as a consequence of cortical damage. Patients with meta- principle of size constancy entails the perception of an object as morphopsia may perceive objects as being smaller or larger than being equally large, irrespective of the viewing distance. If this they actually are (micropsia and macropsia respectively). Other underlying mechanism would be disturbed in patients with forms of metamorphopsia include the perception of curved micropsia, we would expect them to perceive objects smaller instead of straight lines and, in its most dramatic forms, as distorted at greater viewing distances. However, Ceriani et al. (1998)did face perception or an upside down perception of the outside world not find support for this hypothesis in their study. Their patient (Nijboer, Ruis, van der Worp, & De Haan, 2008;Young,deHaan, with micropsia perceived objects smaller than they were in Newcombe, & Hay, 1990).Thesedistortionsaredifferent from reality, regardless of the viewing distance. This indicates that it hallucinations or illusions (Blom, 2016). Distortions are the result is more likely to be a higher-order processing problem, especially of deformations in sensory perceptions in one specificdimension, when both hemifields are affected (Nijboer et al., 2008). Ceriani i.e., perceiving the outside world differently, for instance smaller et al. (1998) explained the micropsia in their patient with another (micropsia) or curved, while illusions are a momentary misinterpre- theory of Bender and Teuber (1949b), in which it was suggested tation of a particular stimulus or situation while the sensory per- that the unilateral brain damage causes a conflict in what is ception is still intact (Blom, 2016). Hallucinations are, in contrast to perceived by the damaged right hemisphere versus what is illusions and distortions, not based on an external stimulus (Waters perceived by the intact left hemisphere. This misbalance or et al., 2014). Metamorphopsia is often transient and is usually only rivalry in the visual perceptual network somehow causes present for several hours or days post-stroke (Blom, 2016). In rare a “micropsic bias” (Ceriani et al., 1998). However, details about occasions, symptoms can last longer (e.g., Ceriani, Gentileschi, the underlying mechanism for this bias remain unknown. Muggia, & Spinnler, 1998). Thus, much is still unknown and a thorough examination of Micropsia is the most common form of metamorphopsia cases with micropsia is needed. In the current study, we (Bender & Teuber, 1949a). Objects can be perceived smaller in examine a case of a patient with micropsia after suffering one hemifield only (Cohen, Gray, Meyrignac, Dehaene, & Degos, a stroke in the right posterior brain region. We conducted 1994; Kassubek et al., 1999), but it is more common that both three experiments, in which we aimed to find an objective visual fields are equally affected (Ceriani et al., 1998;Mullan& way to quantify the extent of the micropsia, to investigate Penfield, 1959; Russell & Whitty, 1955;Smith,1980). Damage to grasping behavior in this patient and to investigate whether the occipito-temporo-parietal brain region has been found to be the micropsia involved both visual fields. In line with the related to micropsia (Brumm et al., 2010; Ceriani et al., 1998; theory of a functional rivalry, we expect that the micropsia Cohen et al., 1994). More specifically, a lesion affecting affects both hemifields. Furthermore, we experimentally tested Brodmann area (BA) 19 has been found to cause hemimicropsia the visual functions separately for each hemifield. By means of (Kassubek et al., 1999). However, details about the lesion locali- this, we aimed to determine possible lateralized visual sensory zation in cases of whole-field micropsia remain unclear. deficits as a source of the functional rivalry in the visual CONTACT Nils S. van den Berg [email protected] Present affiliation for Peter Jan van Laar: Department of Radiology, Zorggroep Twente, Almelo and Hengelo, The Netherlands. © 2019 The Author(s). Published by Informa UK Limited, trading as Taylor & Francis Group. This is an Open Access article distributed under the terms of the Creative Commons Attribution-NonCommercial-NoDerivatives License (http://creativecommons.org/licenses/by-nc-nd/4.0/), which permits non-commercial re-use, distribution, and reproduction in any medium, provided the original work is properly cited, and is not altered, transformed, or built upon in any way. NEUROCASE 203 perceptual network. Lastly, we used structural Magnetic on the left side of the page. Explicitly focusing on the left side Resonance Imaging (MRI) to ascertain the responsible brain on the page helped him to overcome these problems. lesion. Apart from his visual complaints, most things went well. The initial problems with his left arm were improving. After three months, he still tired easily but this was also getting better. Case report Ethics statement Imaging This study was approved by an ethics committee and performed The first MRI (17 December 2017, before the onset of the in accordance with the principles of the Helsinki Declaration and micropsia) showed several subacute infarcts in the right par- the Medical Research Involving Human Subjects Act (WMO). ietal and occipital lobe (Figure 1(a1,b1)). On the second MRI A written informed consent was obtained. (8 February 2018), there was an increase in size and extension of the several Fluid Attenuated Inversion Recovery (FLAIR) hyperintens (sub)cortical regions throughout the right parietal Case summary and occipital lobe, as can be seen in Figure 1(a2,b2,c and d). DN, a 64-year-old man with higher vocational education, was The new lesions involved mainly the cuneus, occipital pole, admitted to the hospital with a hemiparesis of his left arm on inferior parietal lobule and the angular gyrus. There was also fl 28 December 2017. Eleven days before this admission, DN an increase in surrounding con uent white matter hyperinten- already had complaints of temporary loss of vision (amurosis sity with atrophy in the right parietal and occipital lobe. In fugax) after which an MRI-scan was made (17 December 2017). conclusion, there was an increase in size and extension of This MRI-scan showed an infarction in the right occipital and infarction throughout the right parietal and occipital lobe. parietal lobe. The CT-scan performed on 28 December 2017 ff showed an increase of infarction, a ecting a larger area of the Neuropsychological assessment right occipito-parietal region. After 28 December 2017, DN described seeing everything at Neuropsychological assessment showed intact orientation in seventy percent of the actual size. This included both objects time and place (Cognitive Screening Test). DN’s premorbid and persons. When looking in the mirror, he also perceived verbal intelligence was estimated at above average (National himself at seventy percent of his actual size.