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					How spatial attention modulates reading
aloud and lexical decision: Evidence from
    Italian neglect dyslexia patients

                           Lisa S. Arduino
                 University of Milano-Bicocca, Milan
        ISTC-CNR and Fondazione S. Lucia, IRCCS, Rome
                           Cristina Burani
Institute of Science and Technology of Cognition ISTC-CNR, Rome
                          Giuseppe Vallar
                    University of Milano-Bicocca

    The Third International Conference on the Mental Lexicon Banff,
                   Alberta, Canada October 6-8, 2002.
               NEGLECT DYSLEXIA (ND)
UNILATERAL SPATIAL NEGLECT: disturbance in perceiving,
representing and orienting attention to the controlesional side of
space.

       LESION: RIGHT INFERIOR PARIETAL LOBULE
                 (Bisiach & Vallar, 2000; Vallar et al.,
                 1998)

       NEGLECT DYSLEXIA: SINGLE WORD READING (egocentric
       coordinate frames)


              TARGET:       ALBERO “tree” (Ellis et al. 1987)
              SUBSTITUTION: POBERO
              OMISSION:       BERO
              ADDITION:    COSBERO
                     DISSOCIATIONS
• Làdavas et al. (1997, Neuropsychologia): Simple words and
  nonwords presented centrally (9 patients)
                     POOR READING ALOUD
                                 BUT
       PRESERVED LEXICAL DECISION AND
                SEMANTIC JUDGEMENT
• Vallar et al. (1996, Journal of Clinical and Experimental
Neuropsychology): compound words (E.S.)

                                        *camposanto= cemetery
                                        *campo= field
        camposanto
            x                           *santo= saint
                               Severe ND in reading aloud
                               BUT appropriate association
                               (e.g., coffin)
                 Explanations
• Reading aloud differs from lexical decision
  (semantic judg. and associations) for:

     • Diffculty: lexical decision is easier than reading
       aloud and requests less information from the left
       side (guessing strategy).

     • The different involvement of spatial co-ordinate
       frames (Vallar et al., 1996).

     • The differential use of reading routes (Ladavas et
       al., 1997): DRC model (Coltheart et al., 2001).
                     Written stimulus



 The route   ORTHOG.                              The route
  operates   LEXICON
                                          G       operates
on the whole                              P       serially:
word- form:           Semantic            C       attentional
                      s
     NO                                           scanning
 attentional                              rules   from
  scanning    PHONOL.                             left-to-right
             LEXICON




                        Phonemic buffer


                           OUTPUT
          The present study

• Aimed at specifying in further detail the
  preserved lexical processing in patients with
  left ND by exploring in LD tasks, the effect
  of morpho-lexical variables, which
  influence the performance of Italian
  unimpaired subjects.
                     EXPERIMENT 1

    Morphologically simple words and nonwords

• Dissociations between reading aloud (RA) and LD in
  neglect dyslexia patients: the same stimuli presented to six
  patients for both RA and LD (Arduino et al., 2002, Cognitive
  Neuropsychology). Untimed presentation.


• LD accuracy: The six patients were compared to 12
  controls (matched for age, sex and educational level)

• Lexical effects in LD: four patients’ LD performance was
  compared to that of non neurological younger adults.
  Timed presentation (500 or 700 ms.)
                    EXPERIMENT 1


LIST: 240 simple words and nonwords
DEPENDENT VARIABLE: errors
PROCEDURE: untimed (all) timed (4 patients)


A) 40 WORDS:
High and Low surface frequency (50%).

B) 72 BISYLLABIC NONWORDS (5-6 letters).
       Neighborhood frequency (High/Low)

BRISI: CRISI
NERPE: SERPE
                          60              RA
                                          LD
                          50
   Experiment 1
                          40
RA and LD: patients   %
     % errors             30

                          20

                          10

                           0
                               P.P.    M.N.   C.I.   F.S.   A.A.   A.A.


                          10          patients
                                      controls

   Experiment 1
  LD: patients vs.    %    5
     controls
    % errors

                           0
                               P.P.    M.N.   C.I.   F.S.   A.G.   A.A.
                         ESP. 1
      LD with timed presentation (500 ms.): 4 patients
     High and Low frequency words: % correct answers.


           100


            95
       %


            90                                    HF
                                                  LF
            85

            80
                 P.P.   M.N.    C.I.   F.S.


• High-frequency words are recognized faster and with less
  errors than low-frequency words (Colombo, 1992,
  JEP:HPP; Burani et al., 2002, Brain and Language)
                      EXP. 1
   LD with timed presentation (500 ms.): 4 patients
Nonwords with High/Low frequency neighbor: % errors

             25

                  HF     LF
             20

             15
         %




             10

              5

              0
                  P.P.        M.N.   C.I.   F.S.



 BRISI: CRISI
 NERPE: SERPE
LD: non neurological subjects (Arduino & Burani, accepted, JPR)



                                       HF-neigh    LF-neigh
Stimuli: the same
                                 630
Participants: 49
   university students
Dependent variable:
   RT and errors            Rt   620




                                 610

               Error analysis showed the same pattern
                   EXPERIMENT 2

 Morphologically complex words and nonwords

• Dissociation between RA and LD in neglect dyslexia
  patients: the same stimuli presented to six patients for
  both RA and LD (Arduino et al., 2002). Untimed
  presentation.

• LD accuracy: The six patients were compared to 12
  controls (matched for age, sex and educational level)

• Lexical effects in LD: three patients’ LD performance
  compared to non neurological younger adults. Timed
  presentation (700 ms.)
                              EXP. 2
LIST: 300 morphologically complex words and nonwords
DEPENDENT VARIABLE: errors
PROCEDURE: untimed (all) timed (3 patients)

  • A) 88 suffixed derived words (Burani & Thornton,
     2002, Linguistics). All words were low frequency
          • 44 with HF root (CONSUM-ISMO “consumerism”)
          • 44 with LF root (SIMBOL-ISMO “simbolism”)



  • B) 138 nonwords (Burani et al., 1997, Yearbook of
    Morphology; Burani et al., 1999, Brain and Language)
                LAMPAD-ISTA (R+S+)
                RONDIN-OSTO (R+S-)
                ROVOLL-ISMO (R-S+)
                MEVIN-OSTO (R-S-)
                          70                     RA
                                                 LD
                          60
      Exp. 2              50
RA and LD: patients   %   40

     % errors             30
                          20
                          10
                              0
                                   P.P.   M.N.    C.I.   F.S.   A.A.   A.A.



                              15
                                          patients
                                          controls
       Exp. 2                 10

  LD: patients vs.        %
     controls
                               5
    % errors

                               0
                                   P.P.   M.N.    C.I.   F.S.   A.G.   A.A.
                     EXP. 2
   LD with timed presentation (700 ms.): suffixed
                  derived words

                                     subjects   patients


• Burani &                    20
                              18
  Thornton                    16
  (2002): less     % errors   14
  errors in                   12
                              10
  deciding                     8
  upon words                   6
  with high-                   4
                               2
  frequency                    0
  root.                            HF root       LF root
                        EXP 2
         LD with timed presentation (700 ms.):
          morphologically complex nonwords

• Burani et al. (1997,              20
  1999); Burani &                                 patients

  Thornton (2002):                  15




                         % errori
  more errors on
                                    10
  nonwords that
  included either one                5
  or two constituent
  morphemes with                     0
  respect to nonwords                    R+S+   R+S-   R-S+   R-S-
  with no morphemes
                    Summary
The results of both experiments confirmed that
neglect dyslexia patients’ lexical decision:

•is preserved compared to reading aloud;

•is normal compared to the performance of control
subjects;

Moreover the results show that LD:

•is affected by the same morpho-lexical
characteristics that influence non neurological
younger adults;

•is not related to the severity of neglect dyslexia
             60               RA
Exp. 1       50
                              LD


             40
         %
             30

             20

             10

              0
                  P.P.     M.N.   C.I.   F.S.    A.A.   A.A.




             70               RA
                              LD
             60
Exp. 2       50

         %   40
             30
             20
             10
              0
                  P .P .   M.N.   C.I.   F .S.   A.A.   A.A.
                      CONCLUSIONS
• Guessing strategy: The fact that morpho-lexical effects also
  emerged in the patients’ LD allows us to discard the
  hypothesis that the patients adopt a rough guessing strategy
  in LD.
• Differential use of the reading routes (Ladavas et al., 1997):
  LD: good performance because patients made use of the
  lexical route (no serial processing is required)
  RA: impaired performance because patients made use of the
  sublexical route (serial processing, from left-to-right)
                             Moreover
  For some Italian patients the lexical route is available for
  reading aloud (Arduino et al., 2002). It is the availability of
  the lexical route, which makes use of the whole word-form,
  that allows the patients to process the stimuli correctly.
Arduino et al.’s data (2002) may be taken as further
evidence that when patients may have access to the entire
word-form directly, through the lexical route, their
disturbance is ammeliorate because this latter procedure
does not require a sequential, from left-to-right, processing.

                        In conclusion
The dissociation between reading aloud and lexical decision
may be due to the fact that reading aloud requires, at
different processing stage, a left-to-right sequential
processing that is impaired in neglect patients, whereas it is
not required in LD.
• Some authors have suggested that word processing may
  involve two anatomically distinct attentional structures:
  A posterior attentional system which is devoted to the
  allocation of visual spatial attention across the visual field
  (necessary for reading aloud, and which is impaired in
  neglect patients) and a more central anterior attentional
  system (preserved in neglect patients) which plays a role in
  lexical/semantic access (see Carr, 1992, American Journal of
  Psychology, for a review).
READING ALOUD (ARDUINO ET AL, 2002)
                     Written stimulus



 The route   ORTHOG.                              The route
  operates   LEXICON
                                          G       operates
on the whole                              P       serially:
word- form:           Semantic            C       attentional
                      s
     NO                                           scanning
 attentional                              rules   from
  scanning    PHONOL.                             left-to-right
             LEXICON




                        Phonemic buffer


                           OUTPUT
       Demographic features

       S/A/E       Lesion          Duration
P.P    M/77 - 5    Basal ganglia   5
M.N.   F/66 - 12   Fs              1
C.I.   M/47 - 13   FTP             3
F.S.   M/72 - 8    P               7
A.G.   M/63 - 13   Fs              4
A.A.   F/65 - 5    TP              2
   Baseline assessment for visual spatial neglect

         Letter Canc.      Line Canc.    Wundt-Jastrow Reading
         L         R        L      R       L      R
P.P    29\53*    0\51     6\11*   0\10    0\20   0\20    2\6
M.N    28\53*    0\51     0\11    0\10   3\20*   0\20    1\6
C.I.   53\53*    42\51   11\11*   3\10   20\20* 0\20     6\6
F.S.   45\53*    3\51     6\11*   1\10    9\20   8\20    6\6
A.G.   53\53*    37\51   11\11*   1\10    2\20   2\20    6\6
A.A.   53\53*    29\51    6\11*   0\10   7\20*   0\20    6\6
          Reading test (Vallar et al., 1996)


          Words (N=38)    Nonwords (N=38)    Illegal nonwords
                                                  (N=38)
P.P       0\1             11\15   (73.3%)   2\7     (28.6%)
M.N.      4\4     (100%) 13\19    (68.4%)   12\18 (66.7%)
C.I.      0\0             2\2     (100%)    7\7     (100%)
F.S.      1\1     (100%) 18\22    (81.8%)   7\20 (35%)
A.G.      5\7     (71.4%) 15\24   (62.5%)   14\24 (58.3%)
A.A.      22\24   (91.7%) 27\33   (81.8%)   19\35 (54.3%)

       % neglect errors out of the total number of errors
                                       50
                                               high-frq
Exp. 1                                 40      low-frq




                % neglect errors
HIGH\LOW                               30
FREQUENCY
WORDS                                  20

                                       10

                                        0
                                            P.P.    M.N.    C.I.    F.S.     A.G.     A.A.

                                       60
                                                   high
                                       50
Exp. 1                                             low
                    % neglect errors




NONWORDS                               40

WITH HIGH\LOW                          30
FREQUENCY                              20
NEIGHBOR                               10
                                        0
                                            P.P.     M.N.    C.I.     F.S.     A.G.     A.A.
                       Exp. 1
Percent of neglect errors as a function of error type


                       100              substitutions
                                        omissions
                        80
    % neglect errors




                        60
                        40
                        20
                        0
                             P.P. M.N. C.I.   F.S. A.G. A.A.
                      EXPERIMENT 2
  Reading aloud morphologically complex words and nonwords

         Morpho-lexical reading of nonwords (Burani et al., 1997; 1999;
         Burani & Thornton, 2000)

LAMPAD-ISTA (root-suffix: R+S+)
MEVIN-OSTO (no root and no suffix: R-S-)
         Morpho-lexical processing of derived (suffixed) (Burani &
         Thornton, 2000)

BASS-EZZA (high-freq. root and suffix, HH) “Lowness”
BEFF-ARDO (low-freq. root and suffix, LL) “Mocking”

       113 stimuli
       LIST: 300 STIMULI.
        DEPENDENT VARIABLE: ERRORS
        PROCEDURE: UNTIMED AND TIMED (700 msec.).
                          Exp. 2
Percent of neglect errors in reading word and nonword
                         targets

                       60
                                words
                       50
                                nonwords
    % neglect errors




                       40
                       30
                       20
                       10
                        0
                            P.P. M.N. C.I. F.S. A.G. A.A.
                                            70
Exp. 2
DERIVED                                     60          HH




                   % neglect errors
                                            50          LL
(SUFFIXED)
                                            40
WORDS
                                            30
HH: BASS-EZZA                               20
LL: BEFF-ARDO                               10
                                             0
                                                 P.P. M.N.   C.I.   F.S.   A.G. A.A.

                                            80
                                            70      R+S+
Exp. 2
                                            60      R-S-
                          %neglect errors




MORPH.
                                            50
COMPLEX                                     40
NONWORDS                                    30
                                            20
R+S+ LAMPAD-ISTA                            10
R-S- MEVIN-OSTO                              0
                                                 P.P. M.N. C.I.     F.S.   A.G. A.A.
                       Exp. 2
Percent of neglect errors as a function of error type


                          100       substitutions
                                    omissions
                          80
       % neglect errors




                          60
                          40
                          20
                           0
                                P.P. M.N. C.I. F.S. A.G. A.A.
                    RESULTS

• FIVE PATIENTS SHOWED LEXICAL EFFECTS IN
  READING, WHILE ONE PATIENT DID NOT (A.A.)

• FEW ERRORS IN READING
       – words vs. nonwords (Exp. 1 and 2)
       – high vs. low-frequency words (Exp. 1)
       – nonwords with no high-frequency neighbor
         (Exp.1)
       – derived words with high-frequency
         constituents (root and suffix). (Exp. 2)
       – morph. complex nonwords with real root and
         suffix (Exp. 2)
                  CONCLUSIONS
The two types of neglect dyslexia are different
manifestations of a single attentional disorder,
different in degree.

       Relationship between the severity of the
       attentional disturbance and the presence
       vs. absence of lexical effects in reading.

       BUT: Relationship between
       the severity of left neglect and
       lexical effects is specific to the domain
       of neglect dyslexia, and not extending to
       other manifestations of the disorder.
       Baseline assessment for visual spatial neglect

            Letter Canc.      Barrage      Wundt-Jastrow
            L         R      L       R      L       R


C.I.      53\53*   42\51   11\11*   3\10   20\20*   0\20   8%


A.A.      53\53*   29\51   6\11*    0\10   7\20*    0\20   53%


   Percentage of reading errors committed by the two patients
   under condition of unconstrained time (Exp. 1 and 2)
These results suggest that neglect dyslexia reflects a form
of impairment in the spatial allocation of attention or in
spatial representation, specific to the domain of the
reading system. By and in line with this view, neglect
dyslexia has been described in the absence of other
manifestations of neglect symptoms for nonverbal
material (Bisiach et al., 1990), or involving the one side of
space opposite to the one where neglect for nonverbal
material is present (Cubelli et al., 1991; Riddoch et al.,
1995).
   Relationship between error type
         and lexical effects

       Exp. 1   Exp. 2      Subst./Omiss.
P.P    Yes      Yes         Substitutions
M.N.   Yes      Yes         Substitutions
C.I.   Yes      Yes         Omissions
F.S.   Yes      Yes         Omissions
A.G.   Yes      No          Omissions
A.A.   No       No          Omissions
                                                        substitutions
                                           100
                                                        omissions
                                            80




                         %neglect errors
                                            60
   EXP. 1 (6.0)
                                            40
                                            20
                                            0
Mean stimuli length                              P.P. M.N. C.I.   F.S. A.G. A.A.


                                           100       substitutions
                                                     omissions
                                           80
                      % neglect errors




   EXP. 2 (8.3)                            60
                                           40
                                           20
                                             0
                                                 P.P. M.N. C.I. F.S. A.G. A.A.
• Within a left-to-right gradient interpretation of left neglect
the assumption can be made that the longer is the letter string
the more degraded is the internal representation of its left side.

• The increase in omissions with longer letter strings represents
a counterpart, in the reading domain of the well known effect
of line length in segment bisection: The rightward shift of the
subjective midpoint increases with longer lines (Vallar et al.,
2000; Bisiach et al., 1983).

•Within this interpretative framework the more material is to
be computed on the left side of the letter string, the greater is
the probability of a defective processing, that is of an omission
error.
Length effect. Percentage of neglect errors to 5-6 vs.
7-11 letter targets (data from Exp. 1 and 2).


                       70
                       60           5-6
    % neglect errors




                       50           7-11
                       40
                       30
                       20
                       10
                        0
                            P.P.   M.N.    C.I.   F.S.   A.G.   A.A.
The relationship between error types (sub. vs. omiss.)
the severity of the attentional disorder and lexical
effects also falls along a continuum:

• Large majority of omissions may be associated with
a more severe attentional disorder and with the
absence of lexical effects in reading.

• A large majority of substitutions may be associated
with preserved lexical effects and a less severe
attentional disorder.

				
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