Affiliations: Department of Neurological Sciences, University of
Milan Medical School, IRCCS Ospedale Maggiore-Policlinico, Mangiagalli e Regina
Elena – IRCCS Istituto Auxologico Italiano, Milano, Italy | Department of Neurology and Laboratory of
Neuroscience, 'Dino Ferrari Center', University of Milan Medical School, IRCCS
Istituto Auxologico Italiano, Milano, Italy
Note: [] Corresponding author: Dr.~Stefano Zago, Dipartimento di Scienze
Neurologiche, IRCCS, Fondazione Ospedale Maggiore-Policlinico, Mangiagalli e
Regina Elena, Centro Dino Ferrari, Università degli studi di Milano, via
Francesco Sforza 35, 20135 Milano, Italy. Tel.: +39 02 55033854; E-mail:
stefano.zago@unimi.it
Abstract: The present study aims to demonstrate that errors when writing are
more common than expected in patients affected by primary lateral sclerosis
(PLS) with severe dysarthria or complete mutism, independent of spasticity.
Sixteen patients meeting Pringle's et al. [34] criteria for PLS underwent
standard neuropsychological tasks and evaluation of writing. We assessed
writing abilities in spelling through dictation in which a set of words,
non-words and short phrases were presented orally and by composing words using
a set of preformed letters. Finally, a written copying task was performed with
the same words. Relative to controls, PLS patients made a greater number of
spelling errors in all writing conditions, but not in copy task. The error
types included: omissions, transpositions, insertions and letter substitutions.
These were equally distributed on the writing task and the composition of words
with a set of preformed letters. This pattern of performance is consistent with
a spelling impairment. The results are consistent with the concept that written
production is critically dependent on the subvocal articulatory mechanism of
rehearsal, perhaps at the level of retaining the sequence of graphemes in a
graphemic buffer. In PLS patients a disturbance in rehearsal opportunity may
affect the correct sequencing/assembly of an orthographic representation in the
written process.
