Clinical and anatomical correlates of apraxia of speech

In a previous study (Dronkers, 1996), stroke patients identified as having apraxia of speech (AOS), an articulatory disorder, were found to have damage to the left superior precentral gyrus of the insula (SPGI). The present study sought (1) to characterize the performance of patients with AOS on a classic motor speech evaluation, and (2) to examine whether severity of AOS was influenced by the extent of the lesion. Videotaped speech evaluations of stroke patients with and without AOS were reviewed by two speech-language pathologists and independently scored. Results indicated that patients with AOS made the most errors on tasks requiring the coordination of complex, but not simple, articulatory movements. Patients scored lowest on the repetition of multisyllabic words and sentences that required immediate shifting between place and manner of articulation and rapid coordination of the lips, tongue, velum, and larynx. Last, all patients with AOS had lesions in the SPGI, whereas patients without apraxia of speech did not. Additional involvement of neighboring brain areas was associated with more severe forms of both AOS as well as language deficits, such as aphasia.     

Neuroanatomically separable effects of imageability and grammatical class during single-word comprehension

The present study characterizes the neural correlates of noun and verb imageability and addresses the question of whether components of the neural network supporting word recognition can be separately modified by variations in grammatical class and imageability. We examined the effect of imageability on BOLD signal during single-word comprehension of nouns and verbs. Subjects made semantic similarity judgments while undergoing functional magnetic resonance imaging (fMRI). Nouns and verbs were matched on imageability, and imageability varied continuously within a grammatical category. We observed three anatomically separable effects: a main effect of grammatical class, a main effect of imageability, and an imageability by grammatical class cross-over interaction. The left superior parietal lobule and a region in the left fusiform responded similarly to increases in noun and verb imageability; the left superior temporal gyrus showed greater activity for verbs than nouns after imageability was matched across grammatical class; and, in both the left middle temporal gyrus and the left inferior frontal lobe, a decrease in noun but not verb imageability resulted in higher BOLD signal. The presence of reliable and anatomically separable main effects of both imageability and grammatical class renders unlikely the hypothesis that previously reported dissociations between nouns and verbs can be dismissed as imageability effects. However, some regions previously thought to respond to grammatical class or imageability instead respond to the interaction of these variables.     

Temporal variations in visual completion: a reflection of spatial limits?

The completion of partly occluded objects appears instantaneous and effortless, but empirically takes measurable time. The current study investigates how amount of occlusion affects the time course and mechanisms of visual completion. Experiment 1 used a primed-matching paradigm to determine completion times for objects occluded by various amounts. Experiments 2 and 3 used a dot-localization paradigm to probe completed contour representations for a qualitative shift above some spatial limit. The results demonstrate that time to completion rises with amount of occlusion. Nonetheless, the visual system can complete highly occluded objects, even when the occlusion renders visible contours nonrelatable. Furthermore, prolonged completion times for highly occluded objects do not result from a breakdown of low-level interpolation processes: The same contour completion mechanism operates on objects occluded by different spatial extents.     

Assessing the importance of letter pairs in reading-parafoveal processing is not the only view: reply to Inhoff, Radach, Eiter, and Skelly (2003)

D. Briihl and A. W. Inhoff (1995; see record 1995-20036-001) found that exterior letter pairs showed no privileged status in reading when letter pairs were presented as parafoveal primes. However, T. R. Jordan, S. M. Thomas, G. R. Patching, and K. C. Scott-Brown (2003; see record 2003-07955-013) used a paradigm that (a) allowed letter pairs to exert influence at any point in the reading process, (b) overcame problems with the stimulus manipulations used by Briihl and Inhoff (1995), and (c) revealed a privileged status for exterior letter pairs in reading. A. W. Inhoff, R. Radach, B. M. Eiter, and M. Skelly (2003; see record 2003-07955-014) made a number of claims about the Jordan, Thomas, et al. study, most of which focus on parafoveal processing. This article addresses these claims and points out that although studies that use parafoveal previews provide an important contribution, other techniques and paradigms are required to reveal the full role of letter pairs in reading.     

Early morphological effects in reading: Evidence from parafoveal preview benefit in Hebrew

Hebrew words are composed of two interwoven morphemes: a triconsonantal root and a word pattern. We examined the role of the root morpheme in word identification by assessing the benefit of presentation of a parafoveal preview word derived from the same root as a target word. Although the letter information of the preview was not consciously perceived, a preview of a word derived from the same root morpheme as the foveal target word facilitated eye-movement measures of first-pass reading (i.e.,first fixation and gaze duration). These results are the first to demonstrate early morphological effects in the context of sentence reading in which no external task is imposed on the reader, and converge with previous findings of morphemic priming in Hebrew using the masked priming paradigm, and morphemic parafoveal preview benefit effects in a single-word identification task.     

Aging, working memory, and discrimination learning

Older adults easily learn probabilistic relationships between cues and outcomes when the predictive event is the occurrence of a cue, but have greater difficulty when the predictive event is the nonoccurrence of a cue (Mutter & Pliske, 1996; Mutter & Plumlee, 2004; Mutter & Williams, 2004). This study explored whether this age-related deficit occurs in a simpler learning context and whether it might be related to working memory (WM) decline. We gave younger and older adults simultaneous discrimination tasks that allowed us to compare their ability to learn deterministic relationships when either the occurrence (feature positive; FP) or the nonoccurrence (feature negative; FN) of a distinctive feature predicted reinforcement. We also included a group of younger adults who performed the discrimination tasks under a concurrent WM load. Both age and WM load had a detrimental effect on initial FP and FN discrimination; however, these effects persisted only in FN discrimination after additional learning experience. Learning predictive relationships requires inductive reasoning processes that apparently do not operate as efficiently in individuals with reduced WM capacity. The impact of WM decline may ultimately be greater for negative cue-outcome relationships because learning these relationships requires more difficult inductive reasoning processes, which place greater demands on WM.     

A Descriptive Study of Pain and Quality of Life following Guillain-Barré Syndrome: One Year Later

Guillain-Barré syndrome (GBS) is a debilitating immunopathy that afflicts approximately 5,000 patients annually in the United States, a number that represents roughly half of the incidence of spinal cord injuries (J. M., Meythaler, 1997). Of these 5,000 new cases per year, 4–15% will die, 20% will possess deficits in ambulation or require ventilator assistance more than one year later, and more than two-thirds will have persistent fatigue (J. M., Meythaler, 1997; Hughes et al., 2003). These figures suggest that GBS is currently a legitimate cause of long-term disability.Many secondary complications may follow GBS that include dysautonomia, deep vein thrombosis, anemia, immobilization, and pain and sensory involvement (J. M., Meythaler, 1997; J. M. Meythaler, M. J. De Vivo, and W. C. Braswell, 1997). These medical complications have not been studied systematically, and the psychosocial complication of pain following GBS has certainly been overlooked in the literature. The present paper utilized a limited sample of 18 patients (N = 18) with persistent motor deficits at least one year after onset of GBS. We examined their pain and perceived quality of life as part of an ongoing federally funded study which will ultimately attempt to determine if 4-aminopyridine (4-AP) significantly improves motor function in patients with residual weakness from GBS. Findings suggest that while most persons do not rate themselves as depressed one year after GBS onset, 22% of respondents did exceed the cutoff for clinical depression on the CES-D. Age and gender do not appear to be related to any component of pain in GBS; however, self-ratings of physical and mental health do appear to be significantly related to pain experience. The nature of this relationship was not determined, and merits further investigation in future studies.     

Subversive Redemption in Psychoanalysis

Subversive redemption—the sense of overturning the conventional order of things in order to recover lost parts of the self—is a virtually neglected topic in psychoanalysis. With free association, Freud empowered patients to harness unconventional thoughts and feelings. Patients who engage in subversive redemption frequently have a strong sense of agency prompting them to open up in new ways in lieu of “playing it safe.” When patients begin to express certain forbidden ideas, the boundaries of analysis are broadened, freeing the analytic pair to become fully authentic. Psychoanalysis provides patients with an arena to renew themselves as they risk “killing off” their status quo positions to achieve the paradox of living more dangerously in the safety of the analytic surrounds. Patients then feel more confident about undertaking the process of subversive redemption in the wider world.