The followingis related to the case study of a 68 year old man, G.
F. who showed neurologicaland neuropsychological side-effects after suffering an internal capsularstroke. One of the symptoms experienced was persistent left unilateral mirror-writing.This is an analysis of the original case study along with a discussion on theauthor’s claims and their limitations in clarifying the nature of mirrorwriting. G.
F is a retired 68 year old man who in July 2006, at age66, suddenly manifested right sided motor-difficulties after a spontaneousstroke due to an intracerebral-hematoma. On his assessment on the EdinburghHandedness Inventory (1971), he resulted to be left-handed (handedness score:-63/100). However, it was imposed on him as a child to write with his righthand and he had never used his left hand for writing since. The patient’sneuropsychological state was assessed twenty days after the occurrence of theincident. G.
F. was found to be generally cooperating and well orientated intime and space. However, his neurological examinations showed a righthemiparesis (unilateral paresis) without somatosensory or visual field defects.A frontal and sagittal MRI scans show a left subcortical lesion infringing uponthe thalamus, internal capsule and putamen (Angelino et al., 2010). The patientalthough fully communicative with verbal comprehension when speakingspontaneously his speech sounded mildly dysarthric and anomic (Token Test 26/52:Huber Poeck Weingier & Willmes, 1991). The initial neuropsychologicalbattery of tests concluded that the patient showed no sign of cognitivedefects, apart from his left handed writing. During the neuropsychologicalassessment G.
F involuntarily started writing from the right and then proceedingtowards the left. The syndrome is named mirror writing (MW) as in the mirroringimage of canonical writing (right to left), and often appears as a side effectin stroke but does not persist (Maurizo wt al., 2011).
Two years after hisinitial assessment, the patient was recovering motor skills in his right arm,however he did retain involuntary MW in his left.G. F’s case of persistent involuntary MWwas analysed by the authors through a dichotomy of two theoretical MWexplanations: general aspects of spatial cognition and graph-motor. The testsadministered analysed cognitive flexibility (Trait Marking Test, Wisconsin CardSort Test), spatial cognition with mirror reading tasks (Ciurli, Marangolo , 1996), right-left confusion task (Heilman et al., 1980), spatialdiscrimination defect (Heilman et al., 1980) or motor production processes, usingmirror errors in non-graphic tasks (Della Sala & Cubelli, 2007), writing todictation in left and right hemisphere (Bauxbaum et al. 1993) and effects ofverbal cue (Kim et al.
, 2008). The literature suggests that everyday objectsare stored in engrams using only one dominant hemisphere (right) and storingmirror-images in the non-dominant hemisphere (left) (Nas, 1987). G.
F. was able to voluntarily manipulate hand motor programs and write incanonical fashion with his left hand after receiving precise instructions fromthe researchers. The authors suggested that the lesion determined an impairmentof autonomic transformation and interfered not with visual strategies.
The patient also showed signs ofdefective cognitive flexibility, anosognosia (lack of insight) andanosodiaphoria (lack of concern) (e.g. Angelillo et al., 2010). This wasinterpreted by the authors as the explanation for the persistence of his M.W.
The results of this case study support agraph-motor explanation meaning that MW is a defect of motor skills thatpersisted through a defective cognitive flexibility.The explanation however, seems onesided. As there have been cases where analogues phenomena are known to affectperception. A parietal lobe damage can induce an inability to tell apartmirror-images, even though the patient retains the ability to spot subtlechanges in shape and rotation (Davidof & Warrington, 2001; Turnbull , 1996). This type of mirror-confusions at times co-occur withmirror-writing (Heilan et al., 1980; Wade & Hart, 1991). The motor explanationof WM, does not entitle an advantage for reading mirrored texts.
However, in someaccounts perception was entirely reversed enabling fluent mirror-reading andshowing involuntary MW (Gottfried et al., 2003; Lambon-Ralph et al., 1997). Onesuch case, is the unusual report of a polyglot woman who after suffering aconcussion, mirror-read and wrote only her first language, Hebrew but notPolish or German (Streifler & Hofman, 1976). She exhibited involuntarymirror writing, affecting the dominant left hand and displayed a range of otherforms of perceptual confusion (inside/outside, above/beneath).
A parallelbetween her reading and writing suggests that involuntary mirror-writing can bein some cases a perceptual or conceptual problem. However, deliberate mirrorwriting can also hold vital information regarding the mechanism behindinvoluntary mirror writing in brain damaged adults. A recent study attempted toaddress this question in KB’s study. An ambidextrous German artist whopracticed various forms of mirror writing with experience of more than 50 years.Using a technique, he developed to half the time spent drawing lines by writingforwards with his right hand and simultaneously backwards with his left.Although some of the patient’s characters matched the motor hypothesis, KB alsoshowed a specific impairment in hand (right and left) discrimination (McIntosh & Salsa, 2012).
The author’s interpreted K.B.’sfacility had entailed an abnormal degree of overall neural motorrepresentations of the hands in the brain. Meaning he could rotate his handsmentally to match a picture but would have problems to introspectively recognisewhich hand made the match.
Simply put KB would have difficulty indistinguishing right from left.