Mirror-reading and writing in association with right-left spatial disorientation

Representations of grapho-motor patterns unique to Chinese character writing: evidence from a patient with mirror writing

This study investigated the grapho-motor patterns used in writing Chinese characters. A Chinese patient, CSC, who demonstrated post-brain-injury mirror writing, was recruited. In Experiment 1, non-mirrored writing responses were obtained when CSC was instructed to copy asymmetrical non-verbal symbols and pictures. Resembling the patterns observed in a patient's writing reported in a previous study, it was hypothesized that CSC's mirror writing was a result of untransformed preserved grapho-motor patterns. In Experiments 2 and 3, CSC was further instructed to copy real Chinese characters, pseudo-characters with authentic radicals and logographemes (i.e., stroke clusters that frequently occur in radicals), and Hangul characters with stroke clusters resembling the shapes of authentic logographemes. The results showed that CSC demonstrated mirror writing only when authentic Chinese orthographic units were involved. Non-mirrored writing responses were obtained from stimuli without authentic Chinese orthographic units. In sum, CSC's performance supported the existence of grapho-motor patterns of Chinese orthographic units represented in the brain. Theoretical implications were discussed.

Transient involuntary mirror writing triggered by anxiety

Mirror writing (MW) has mainly been observed in left-hemisphere-damaged patients writing with the left hand. This study evaluated the presence of MW in 24 patients with mild cognitive impairment (MCI). We found that MW is not a typical feature of MCI. However, one woman (FC), mislabeled initially with MCI but in fact affected by anxiety, showed florid MW when writing with her left hand, which resolved as her anxiety receded. This case study supports anecdotal reports of MW triggered by anxiety, and the features of FC's performance indicate a motor rather than a perceptual basis for the phenomenon.

Mirror man: a case of skilled deliberate mirror writing

Mirror writing is a striking behaviour that is common in children and can reemerge in adults following brain damage. Skilled deliberate mirror writing has also been reported, but only anecdotally. We provide the first quantitative study of skilled deliberate mirror writing. K.B. can write forward or backward, vertically upright or inverted, with the hands acting alone or simultaneously. K.B. is predominantly left handed, but writes habitually with his right hand. Of his writing formats, his left hand mirror writing is by far the most similar in style to his normal handwriting. When writing bimanually, he performs better when his two hands make mirror-symmetrical movements to write opposite scripts than if they move in the same direction to write similar scripts. He has no special facility for reading mirrored text. These features are consistent with prior anecdotal cases and support a motor basis for K.B.'s ability, according to which his skilled mirror writing results from the left hand execution of a low-level motor program for a right hand abductive writing action. Our methods offer a novel framework for investigating the sharing of motor representations across effectors.

Brain activation associated with practiced left hand mirror writing

Mirror writing occurs in healthy children, in various pathologies and occasionally in healthy adults. There are only scant experimental data on the underlying brain processes. Eight, right-handed, healthy young adults were scanned (BOLD-fMRI) before and after practicing left-hand mirror-writing (lh-MW) over seven sessions. They wrote dictated words, using either the right hand with regularly oriented writing or lh-MW. An MRI compatible stylus-point recording system was used and online visual feedback was provided. Practice resulted in increased speed and readability of lh-MW but the number of movement segments was unchanged. Post-training signal increases occurred in visual, right lateral and medial premotor areas, and in right anterior and posterior peri-sylvian areas corresponding to language areas. These results suggest that lh-MW may constitute a latent ability that can be reinstated by a relatively brief practice experience. Concurrently, right hemisphere language processing areas may emerge, reflecting perhaps a reduction in trans-hemispheric suppression.

Mirror writing: a tachistoscopic study of a woman suffering from migraine when writing with the right hand

An experimental study was conducted with a young woman who had suddenly developed mirror writing in the right hand, which she used for writing. She was not cured for eight years. The patient was ambidextrous and had no medical complaints except for migraine with perceptual and sensory abnormalities, and an enlarged cavity of the septum pellucidum. A previous study using functional magnetic resonance imaging (fMRI), conducted when she imagined letters and wrote letters in the air with either hand, indicated that both her cerebral hemispheres were active. In the present study three experiments were conducted using a tachistoscope to explore the stage in the cognitive process when directional errors emerged. In the experiments, after independently being presented with Attneave's meaningless figures or letters to each hemisphere, participants were requested to do the following: (a) verbally respond whether the orientation of two consecutively shown figures were the same or different and the letters were standard or reversed; (b) distinguish the orientations with right and left hand movements other than by writing (by pushing a button); and (c) reproduce the stimuli (drawing) immediately after the presentation. Results showed a higher rate of incorrect directions only when drawings were reproduced by the right hand. Results also indicated that the woman's inaccurate judgment in direction emerged only when in writing and not at the perceptual level, or when responding with hand movements other than writing. Her migraine was cured after five years following the experiment. The mirror writing was cured 2-3 months later.

Mirror writing resulting from an egocentric representation disorder: a case report

Buchwald (1878 ) used the term 'mirror writing' to indicate writing in the reverse direction to what is normal in a particular language and in which the individual letters are also reversed. Cases of healthy individuals (i.e., Leonardo da Vinci and Lewis Carroll) as well as brain-damaged patients have been described in the literature. Here, we report the case of PM, a 70-year-old right-handed woman who showed right hemiplegia and mirror writing following a stroke in the left lenticular nucleus and internal capsulae. PM underwent a complete neuropsychological evaluation, which included copying, dictation and spontaneous writing in both hemispaces with both hands. She was also tested for topographical disorientation, visuo-spatial disorders and body schema deficits. We observed isolated mirror writing only when PM wrote with the left hand, without differences between hemispaces. She also showed a left-right disorientation, a body topological map disorder and an egocentric misrepresentation. The presence of mirror writing not confined to one hemispace and the co-presence of executive function disorders, as well as anosognosia, suggests damage to our patient's sub-cortical frontal network. As no previous interpretation fits with PM's symptoms, we hypothesize that mirror writing resulted from damage to her egocentric frame of reference. This hypothesis allows us to interpret the patient's array of disorders, including mirror writing, body topological map disorder, left-right confusion and egocentric representation.

Mirror-image discrimination and reversal in the disconnected hemispheres

Two callosotomized patients and 24 neurologically normal subjects performed simple binary discriminations between upright letters flashed in one or other visual field. Where discrimination of the letters F and R by name either showed a left-hemisphere advantage or no hemispheric effect, discrimination of whether the same letters were normal or backward showed a right-hemisphere advantage. These results suggest that discrimination of mirror-image letters depends on matching to an exemplar, for which the right-hemisphere is dominant, while letter naming depends on abstract category recognition. One commissurotomized patient, DDV, showed systematic left-right reversal of the letters in the left visual field, classifying the normal letters as reversed and reversed ones as normal, and persisted with this reversal when the letters were shown in free vision. This suggests that reversed exemplars of the letters may be laid down the right cerebral hemisphere. There was no such reversal in the other patient (DDC).

'Directional apraxia': a unitary account of mirror writing following brain injury or as found in normal young children

Mirror writing refers to the production of individual letters, whole words or sentences in reverse direction. Unintentional mirror writing has been observed in young children and brain-damaged people and interpreted as the manifestation of different cognitive impairments. We report on a mirror writing patient following left hemisphere stroke and the mirror writing phenomena in one sample of children learning to write. We propose a unitary account of mirror writing as the unavailability of the appropriate movement direction representation, either because the right configuration has yet to be specified fully (children learning to write) or because of its damage (acquired brain injury). For this reason, we propose that the lack of directional information relevant to writing be labelled 'directional apraxia'.

Mirror writing: neurological reflections on an unusual phenomenon

Mirror writing is an unusual script, in which the writing runs in the opposite direction to normal, with individual letters reversed, so that it is most easily read using a mirror. This writing is seen in healthy individuals; it is also associated with various focal lesions that most commonly involve the left hemisphere, as well as with certain diffuse cerebral disorders. Mirror writing is nearly always undertaken with the left hand, and left-handers, and those whose languages are written leftwards, have an unusual facility for this writing. Concerning possible underlying processes, the implications of using the left hand when writing are considered first. Motor pathways that may be important, the surrogate model of bimanual mirror movements and the contribution of the corpus callosum are then discussed. The reasons why left-handed writing is mirrored, and the factors that tend to inhibit mirroring, are outlined. After commenting on mirrored motor and visual engrams, the possibility that the right hemisphere may play an important part is entertained, and Leonardo da Vinci's unique, habitual mirror writing proves to be of unexpected relevance. Further investigations, ranging from epidemiological to functional imaging studies, may provide valuable insights into mirror writing.

A second Leonardo da Vinci?

We describe a young woman who suddenly began mirror writing with her right hand and has not reverted to normal writing for more than 6 years, although she writes normally with her left hand. She is ambidextrous, although she had previously used only her right hand for writing and drawing. Since it is much easier for her to use right-handed mirror writing, she uses her left hand only for writing meant to be read by others and her right hand for all other writing. Her hobbies are sculpture and painting, and her chief complaint is migraine accompanied by sensory and perceptive disturbances.

Acquired mirror writing and reading: evidence for reflected graphemic representations

Mirror writing occurs when individual letters and whole word strings are produced in reverse direction. By analogy, mirror reading refers to the preference to read mirror reversed over normally written words. These phenomena appear rarely after brain damage and offer insight into the nervous system's organization of visual-spatial and visual-motor representations. We present the case of a 51-year-old patient with persistent mirror writing and reading following traumatic brain injury. She preferred to write in the mirror direction with either hand. She drew asymmetric pictures with the same directional bias as normal right-handed subjects, and she did not exhibit left-right confusion regarding other pictures. By contrast, on picture-word matching and lexical decision tasks, she was faster and more accurate with mirrored than normally written words. This pattern of performance suggests that her behavior was not accounted for by reflected motor programs, or by the mirroring of visual-spatial representations in general. Rather, we suggest that her behavior was produced by privileged access to mirrored graphemes. Furthermore, because she seemed better able to read irregular words in mirrored than in normal formats, we suggest that mirrored representations may exist at the whole word level and not simply at the letter level.

Mirror writing and handedness

It has been reported that left-handed subjects are better able to write in mirror-reversed script than right-handers (Tankle & Heilman, 1983). Vaid and Stiles Davis (1989) conducted studies which led them to contradict the supposed superiority of left-handers in this area. In these studies, left as well as right-handed subjects were examined under normal- and mirror-writing conditions. Both examinations included the analysis of writing time and the accuracy of mirror writing (error rates). Using a digitizing tablet, we examined normal- and mirror-writing performance of left-handers, right-handers, and left-handed subjects who habitually write with their right hand. Our results support the finding of Tankle and Heilman (1983) that left-handers perform better in mirror-writing tasks.

Mirror writing in right-handers and in left-handers: a study using Chinese characters

The mechanism of mirror writing was investigated using legal Chinese characters and illegal pseudocharacters. It was found from the results of right-handers in experiment 1 that the performance of normal writing and mirror writing for legal characters was better than that of normal writing and mirror writing for pseudocharacters. A reasonable explanation for this character-superiority effect is that normal engrams and mirror engrams exist only for legal characters but not for pseudocharacters. Further analysis revealed that the character-superiority effect took place in normal writing only when the right hand was used and the same effect was observed in mirror writing only when the left hand was used. It seemed that the normal engrams used in normal writing were stored in the left hemisphere while the mirror engrams used in mirror writing were stored in the right hemisphere. The results in experiment 2 from the left-handers showed the similar pattern as that of the right-handers. The mirror-engram hypothesis seems to be the best mechanism to account for the performance difference of right hand and left hand in mirror writing.

Hemispatial factors in mirror writing

The effect of the hemispace in which writing was performed was assessed in two left hemisphere stroke patients who demonstrated left-handed mirror writing. Both patients produced significantly more mirrored words when writing in right, as compared to left (body) hemispace. We suggest that writing in the right hemispace activates the left hemisphere. Further, we propose that mirror writing in the right hemispace is attributable to activation of the damaged left hemisphere spatial system, which fails to assist in the translation of right hand motor programs into those appropriate to the left hand. Writing in left hemispace, in contrast, activates the intact right hemisphere based spatial system which guides the execution or monitoring of motor productions in left hemispace. The result is writing which remains directionally correct when the left hand is used in left hemispace.

Hand motor patterns after the correction of left-nondominant-hand mirror writing

In a previous report, the author studied a left-nondominant-hand mirror writer, postulating that her mirror writing resulted from the failure to reverse the right-hand writing motor patterns when transmitted from the left to the right cerebral hemisphere. In this study, the patient was asked to write in normal fashion with the left hand; the result was a mixture of handwriting motor patterns which included normal letters, letters with reversed direction tracings, letters with one or more than one loop-tracings and illegible letters. The author considers this result to be a further support for the above-proposed hypothesis.

Mirror phenomena in language and nonverbal activities--a case report

A case is described of a 38-year-old, left-handed female who demonstrated mirror phenomena for both language and non-motor, nonverbal material. She mirror-wrote with her left hand with normal right-hand writing. Mirror-reading as well as object and spatial reversals were revealed. These data are consistent with bilateral representation of visual engrams, with one hemisphere containing a mirror-reversed representation of the other.

[Temporary mirror writing and mirror reading as disinhibition phenomena? A case study]

After removal of a left parietal meningioma a 74-year-old right-handed woman developed temporary mirror writing and mirror reading. Further analysis of the mirror phenomena came from tachistoscopic hemifield stimulation showing a right hemisphere superiority for the recognition of words presented in mirror fashion. These neuropsychological results are discussed in the context of common concepts. Finally the hypothesis of bihemispheral mirror-image engrams according to Orton will be suggested as a comprehensive explanation and supported by evidence from the literature.

Mirror-writing and reversed repetition of digits in a right-handed patient with left basal ganglia haematoma

A 57 year old right-handed Chinese man sustained a left basal ganglia haemorrhage resulting in speech disorder and right hemiplegia. He mirror-wrote with his left hand and during speech recovery repeated digits in reverse sequence. The abnormal right to left directionality possibly reflected release of right basal ganglia from left-sided control.

Object reversals after parietal lobe infarction--a case report

A case is described of a mixed manually dominant man with a right parietal infarction who demonstrated reversals in object manipulation. Although mirror reversals in parietal lobe dysfunction and right-left spatial reversal in conjunction with mirror writing have been reported previously, object and spatial reversal to this extent has not been reported. The theoretical implications of the absence of mirror writing here, in relation to side of brain lesion and handedness, are discussed.

Mirror writing in right-handers and in left-handers

To determine whether normal left-handers were more adept than were normal right-handers at mirror writing, we tested right-handers and left-handers for their ability to mirror write. Independent of hand used, left-handers wrote mirror words (but not normal words) faster than did right-handers, which suggest that left-handers may be better able to reverse directions (left leads to right to right leads to left). Although when using their preferred hand, left-handers made fewer errors than did right-handers (using their preferred hand), the left hand both in right- and in left-handers was superior to the right hand. That the left hand was superior to the right is compatible with the hypothesis either that the right hemisphere contains mirror engrams or that movements away from the body are more accurate than movements toward the body or both.