Where language meets meaningful action: a combined behavior and lesion analysis of aphasia and apraxia

Abstract

It is debated how language and praxis are co-represented in the left hemisphere (LH). As voxel-based lesion-symptom mapping in LH stroke patients with aphasia and/or apraxia may contribute to this debate, we here investigated the relationship between language and praxis deficits at the behavioral and lesion levels in 50 sub-acute stroke patients. We hypothesized that language and (meaningful) action are linked via semantic processing in Broca's region. Behaviorally, half of the patients suffered from co-morbid aphasia and apraxia. While 24% (n = 12) of all patients exhibited aphasia without apraxia, apraxia without aphasia was rare (n = 2, 4%). Left inferior frontal, insular, inferior parietal, and superior temporal lesions were specifically associated with deficits in naming, reading, writing, or auditory comprehension. In contrast, lesions affecting the left inferior frontal gyrus, premotor cortex, and the central region as well as the inferior parietal lobe were associated with apraxic deficits (i.e., pantomime, imitation of meaningful and meaningless gestures). Thus, contrary to the predictions of the embodied cognition theory, lesions to sensorimotor and premotor areas were associated with the severity of praxis but not language deficits. Lesions of Brodmann area (BA) 44 led to combined apraxic and aphasic deficits. Data suggest that BA 44 acts as an interface between language and (meaningful) action thereby supporting parcellation schemes (based on connectivity and receptor mapping) which revealed a BA 44 sub-area involved in semantic processing.

Distortion of Visuo-Motor Temporal Integration in Apraxia: Evidence From Delayed Visual Feedback Detection Tasks and Voxel-Based Lesion-Symptom Mapping

“…Therefore, the current results showing a significant association between the reduction (severe apraxia) of the AST score and lesions in the left IFG and IPL were consistent with the findings of previous stimulation studies. Previous lesion studies related to apraxia reported that lesions in the left IPL (21, 22, 69, 100–102), left IFG (39, 102, 103), left insula (104), and left precentral gyrus (102) were significantly associated with an impairment of transitive gestures (pantomime). These previous studies, in line with the current results, were performed using brain lesion areas associated with ipsilateral limb errors (apraxic symptoms).…”

Apraxia and spatial inattention dissociate in left hemisphere stroke

“…These tests comprised the (i) imitation of hand positions (n=74) and (ii) finger configurations (n=74; both based on (Goldenberg, 1996), (iii) pantomiming the use of objects (n=72), and (iv) actually using objects/tools (n=74; both based on De Renzi, Pieczuro, & Vignolo, 1968). Following the procedures described in Dovern et al (2011), patients were considered apraxic when they scored below cut-off in at least one of the four apraxia tests (see also (Weiss et al, 2015). …”

“…All lesions were mapped using the free MRIcron software (http://www.mccauslandcenter.sc.edu/mricro/mricron/index.html) and were drawn manually on slices of a T1-weighted template MRI scan (ch2) provided by MRIcron, as previously described (Dovern et al, 2011;Weiss et al, 2015). Lesions were mapped onto axial slices that corresponded to the MNI-z-coordinates from -7 to +58 mm in steps of 5 mm.…”

“…VLSM has been employed to elucidate the neural basis of cognitive deficits after damage to the RH (i.e., neglect (Committeri et al, 2007;Verdon et al, 2010) or the LH (i.e., apraxia (Dovern et al, 2011;Randerath, Goldenberg, Spijkers, Li, & Hermsdörfer, 2010) and aphasia (Baldo, Schwartz, Wilkins, & Dronkers, 2006;Fridriksson, Fillmore, Guo, & Rorden, 2014)). Recently, VLSM has been used to investigate the relationship between apraxic and aphasic deficits after LH damage (Mengotti et al, 2013;Saygin, Wilson, Dronkers, & Bates, 2004;Weiss et al, 2015). In a VLSM analysis, patients are divided into two subgroups on a voxel-by-voxel basis, depending on whether the particular voxel is lesioned or intact.…”

Lateralization of Brain Functions: A Randomized Single-Blinded Observational Study

“…The best case of a set-up lateralization, is that of speech centres known as Broca's and Wernicke's, are almost exclusively located on the on the left hemisphere in right-handed individuals. These ranges much of the time compare to handedness (6)(7)(8)(9) This observational study and cross-sectional analysis was conducted in accordance with the Ethical approval no. 620-73, on the 15th of May 2016.…”