patterns of orthographic working memory impairments in acquired dysgraphia in adults: a case series analysis

Introduction Studies reporting on the occurrence of orthographic working memory (OWM) impairment in cognitive neuropsychology (CN) appear to be limited. However, a recent study offers some evidence that points to the common occurrence of OWM impairments in clinical populations (Haslam, Kay, Tree, & Barron, 2009). But the evidence offered in this study is also limited to three cases with dementia. Thus, the evidence for common occurrence of OWM impairments awaits, at the least, a case series analysis of several cases. Previous studies of OWM impairments in dysraphias have identified characteristic error profile that included length effect, letter errors, and lack of frequency effects (Buchwald & Rapp, 2009). Additionally, letter errors were more common in the middle of words than in the initial or final positions (Zazio, Cappaso, & Miceli, 2013). As the recent debates on case series investigations in CN imply (Schwartz & Dell, 2010; Rapp, 2011), focused cognitive analysis of OWM impairments might reveal the trends and variations in the patterns of occurrence. The present study reports on OWM impairments in four cases with a history of chronic aphasia and dysgraphia. In addition, this study also discusses the variability in the patterns of OWM impairment and reflects on the previously established profiles of impairments. Method Subjects. Four adults with chronic aphasia have served as the subjects of this study: Subject 1:CBH, a 59-year-old, right-handed female with a medical history of stroke-induced bilateral parietal lobe lesion, Subject 2: JL, a 66-year-old, right-handed female with an ischemic stroke affecting posterior temporo-parietal cortex of the left hemisphere and bilateral white matter atrophy, Subject 3: LK, a 45-year old, right-handed male with a stroke induced infarct involving the left temporal region and a portion of the left frontal cortex, and Subject 4: SE, a 69-year-old right-handed female, with a stroke-induced lesion in the right frontal lobe under the anterior horn of the lateral ventricle and the head of caudate and putamen. Procedure Clinical evaluation included administration of the Boston Diagnostic Aphasia Examination (BDAE). Experimental Tests administered include 1) Johns Hopkins University Dysgraphia Battery and 2) Psycholinguistic Assessment of Language Performance in Aphasia (PALPA), specifically the letter length subtests of Reading and Spelling Tests. Results and Discussion The results revealed the presence of letter length effect in all four patients: LK had 17% correct responses, JL had 30% correct responses, CBH had 79% correct responses, and SE had 87% correct responses. These results clearly support the view of common occurrence of OWM impairments (Haslam, Kay, Tree, & Baron, 2009). However, there was a variable letter position pattern in the four patients (Figure 1). SE, who had the least number of errors, among the four patients, was the only case that had a clear bow-shaped pattern. CBH had more errors in the middle letters but did not show a clear bow-shaped pattern. LK and JL had more errors in the initial letters than in the succeeding ones. These findings warrant further research into the importance of letter position for the characterization of OWM impairment profile.