Letters lost in space: hemispace dependent handwriting errors

Although handwriting is a daily life activity commonly attributed to the left hemisphere in the majority of right-handers, it is also known to require attentional and spatial mechanisms that rely on right hemispheric processing. The underlying spatial organization of handwriting in patients with right brain damage remains unresolved. Here we show in a patient with circumscribed right superior parietal damage that handwriting systematically depends on the hand's position in space with respect to her body-midline. Most importantly, handwriting in contralesional space not only leads to spatial but also to language errors. This suggests that the right hemisphere's role in handwriting may surpass its generally assumed purely spatial contribution. We discuss our results in term of co-registration between both cerebral hemispheres in language processing

Characterization of social cognition impairment in multiple sclerosis

Multiple sclerosis (MS) has been associated with deficits in social cognition. However, little is known about which domains of social cognition are predominantly affected and what other factors are associated with it. The aim was (i) to characterize social cognition deficit in a group of MS outpatients and (ii) to relate impairment in social cognition to overall cognitive status, depression and fatigue.Methods: Thirty-five MS patients (mean disease duration 12.9 years, median Expanded Disability Status Scale (EDSS) 3 and 34 healthy controls (HCs) were examined using the German version of the Geneva Social Cognition Scale to measure different domains of social cognition. Standard neuropsychological testing was applied to all patients and to 20 HCs. Patient-reported outcomes included questionnaires for fatigue, depression, anxiety and executive-behavioural disturbances.Results: The mean social cognition raw score was lower in the MS patients compared to the HCs (86.5 ± 8.7 vs. 91.2 ± 5.9, P = 0.005; d = 0.6) and did not correlate with EDSS or disease duration. The difference was driven by facial affect recognition and the understanding of complex social situations (14% and 23% of patients respectively under the cut-off). The impairment in these two tasks did not correlate with general cognitive performance or depression but with fatigue.Conclusions: The impairment in our group was restricted to high order and affective social cognition tasks and independent of general cognitive performance, EDSS, disease duration and depression. Fatigue correlated with social cognition performance, which might be due to common underlying neuronal networks

Number magnitude to finger mapping is disembodied and topological

It has been shown that humans associate fingers with numbers because finger counting strategies interact with numerical judgements. At the same time, there is evidence that there is a relation between number magnitude and space as small to large numbers seem to be represented from left to right. In the present study, we investigated whether number magnitude to finger mapping is embodied (related to the order of fingers on the hand) or disembodied (spatial). We let healthy human volunteers name random numbers between 1 and 30, while simultaneously tapping a random finger. Either the hands were placed directly next to each other, 30 cm apart, or the hands were crossed such that the left hand was on the right side of the body mid-line. The results show that naming a smaller number than the previous one was associated with tapping a finger to the left of the previously tapped finger. This shows that there is a spatial (disembodied) mapping between number magnitude and fingers. Furthermore, we show that this mapping is topological rather than metrically scaled

Touch perception reveals the dominance of spatial over digital representation of numbers

We learn counting on our fingers, and the digital representation of numbers we develop is still present in adulthood [Andres M, et a. (2007) J Cognit Neurosci 19:563-576]. Such an anatomy-magnitude association establishes tight functional correspondences between fingers and numbers [Di Luca S, et al. (2006) Q J Exp Psychol 59:16481663]. However, it has long been known that small-to-large magnitude information is arranged left-to-right along a mental number line [Dehaene S, et A (1993) J Exp Psychol Genet 122:371-396]. Here, we investigated touch perception to disambiguate whether number representation is embodied on the hand ("1" = thumb; "5" = little finger) or disembodied in the extrapersonal space ("1" = left, "5" = right). We directly contrasted these number representations in two experiments using a single centrally located effector (the foot) and a simple postural manipulation of the hand (palm-up vs. palm-down). We show that visual presentation of a number ("1" or "5") shifts attention cross-modally, modulating the detection of tactile stimuli delivered on the little finger or thumb. With the hand resting palm-down, subjects perform better when reporting tactile stimuli delivered to the little finger after presentation of number "5" than number "1." Crucially, this pattern reverses (better performance after number "1" than "5") when the hand is in a palm-up posture, in which the position of the fingers in external space, but not their relative anatomical position, is reversed. The human brain can thus use either space- or body-based representation of numbers, but in case of competition, the former dominates the latter, showing the stronger role played by the mental number line organization

Semantically-triggered reading epilepsy: an experimental case study

Primary reading epilepsy (PRE) is a rare syndrome in which epileptic seizures are electively provoked by reading. Cognitive neuropsychology has demonstrated the existence of at least two pathways for reading, the sublexical pathway involved in converting graphemes to phonemes, and the lexical pathway used when meaning is conveyed. Which of these specific pathways is relevant in triggering epileptic discharges remains largely unknown. We report the case of a patient suffering from PRE in which the two routes were distinguished on the basis of the reading material employed. Significantly less epileptic discharges were observed when the patient read non-words than words. In view of our findings, we tentatively contrast a lexical form of PRE, triggered by the activation of semantic knowledge structures, with a sublexical form, triggered by non-word reading. Evidence from the literature suggests that the former is characterized by bilateral EEG activating patterns, whereas the latter involves preferentially the left hemisphere

Characterization of social cognition impairment in multiple sclerosis.

BACKGROUND AND PURPOSE Multiple sclerosis (MS) has been associated with deficits in social cognition. However, little is known about which domains of social cognition are predominantly affected and what other factors are associated with it. The aim was (i) to characterize social cognition deficit in a group of MS outpatients and (ii) to relate impairment in social cognition to overall cognitive status, depression and fatigue. METHODS Thirty-five MS patients (mean disease duration 12.9 years, median Expanded Disability Status Scale (EDSS) 3 and 34 healthy controls (HCs) were examined using the German version of the Geneva Social Cognition Scale to measure different domains of social cognition. Standard neuropsychological testing was applied to all patients and to 20 HCs. Patient-reported outcomes included questionnaires for fatigue, depression, anxiety and executive-behavioural disturbances. RESULTS The mean social cognition raw score was lower in the MS patients compared to the HCs (86.5 ± 8.7 vs. 91.2 ± 5.9, P = 0.005; d = 0.6) and did not correlate with EDSS or disease duration. The difference was driven by facial affect recognition and the understanding of complex social situations (14% and 23% of patients respectively under the cut-off). The impairment in these two tasks did not correlate with general cognitive performance or depression but with fatigue. CONCLUSIONS The impairment in our group was restricted to high order and affective social cognition tasks and independent of general cognitive performance, EDSS, disease duration and depression. Fatigue correlated with social cognition performance, which might be due to common underlying neuronal networks

Creutzfeldt-Jakob disease revealed by a logopenic variant of primary progressive aphasia

Logopenic aphasia, mainly characterized by word anomia, sentence and phrase comprehension difficulties secondary to phonological loop deficits but relatively preserved single word comprehension and no agrammatism, is one of the 3 main variants of primary progressive aphasia (PPA). We describe the first case of PPA that fulfilled clinical criteria of logopenic aphasia but showed abnormal DWI hyperintensities that were predominant on the left hemisphere and compatible with Creutzfeldt-Jakob disease (CJD). After abnormally long isolated language deficits, the patient rapidly worsened and died. Autopsy performed 18 months after onset of language difficulties confirmed the diagnosis. We therefore advocate performing DWI sequences in any suspicion of PPA in order to rule out CJD

Writing without Graphic Motor Patterns: A Case of Dysgraphia for Letters and Digits Sparing Shorthand Writing

Thi s pape r report s th e cas e of a patien t (H P) wh o present s a dysgraphi a affectin g th e productio n of letter s an d digit s whil e sparin g shorthan d writing . H P' s writin g impairmen t is two-fold . O n on e hand , HP produce s systemati c lette r substitution s affectin g exclusivel y lower-cas e letter s b , p , d , and q . Suc h confusion s ar e als o observe d in task s assessin g th e menta l imager y of letter s an d th e processin g of visuall y presented , isolate d letters . Thi s defici t is attribute d to a circumscribe d disruptio n of allographi c representa tions . On th e othe r hand , H P ca n writ e correctl y forme d letter s an d digit s bu t th e productio n of thes e symbol s is slo w an d nonfluent . Thi s disturbanc e wa s investigate d by usin g a digitisin g table t to recor d movement s performe d in grapho-moto r production . Th e result s of th e analysi s of tempora l an d kinemati c indice s sugges t tha t graphi c moto r pattern s of letter s an d digit s ar e no longe r availabl e to thi s patient , wherea s moto r pattern s underlyin g th e productio n of shorthan d see m unaffected . It is suggeste d tha t ther e ar e tw o way s fo r producin g spatiall y well-forme d symbols . O ne rout e is mediate d by graphi c motor pattern s an d th e other by a motor planning syste m tha t woul d be use d in othe r tasks involvin g the generatio n of 2D trajectorie s (a s in drawin g or in tracing unfamilia r symbols)