Aphasia and the brain: from syndromes to symptoms to computations
For the first 100 years of modern aphasia research (~since the 1860s) the focus was mainly on syndromes: motor (Broca's) aphasia, sensory (Wernicke's) aphasia, conduction aphasia, and so on. Things changed after the Cognitive... er, make that the Information Processing Revolution (see discussion here or here) when symptoms came more into focus. The symptom approach was an important advance and is still dominant, as the popular method, voxel-based lesion-symptom mapping (VLSM), highlights. But mapping symptoms isn't the goal. What we are really after are the computations that underlie the symptoms. Recent work by Gary Dell and colleagues suggests that this might be possible using what they call, voxel-based lesion parameter mapping (VLPM). The basic idea is this. Start with an explicit computational model of the process of interest; Dell et al. use the two-step naming model. Collect data on the symptoms in brain injured patients; for Dell et al, this is the distribution of types of naming errors. Adjust the parameters of your model to fit each patient's error pattern; semantic and phonological weights in the Dell model. Then run your voxel-based analysis using the parameter values as your dependent measure instead of say error rate. And it actually works. To the extent that the model is a reasonable approximation to what's going on in the wetware (no model is "right" of course), you are now mapping computations. &nbs...
Conclusions: We speculated that damages to the basal ganglia disrupted the cortico-subcortical circuits that facilitated the transhemispheric communications of language functions, resulting in decreased interhemispheric FC. Consequently, the intrahemispheric FC increased as a possible compensatory mechanism to restore the language functions. PMID: 31955634 [PubMed - as supplied by publisher]
ConclusionsThis patient demonstrates an unusual presentation of glioblastoma multiforme as thalamic aphasia. It may also point to the potential contribution of the understanding of how thalamic aphasia evolves to characterize the role of the thalamus in language functions.
Publication date: Available online 20 January 2020Source: NeuropsychologiaAuthor(s): Maria Dekhtyar, Swathi Kiran, Teresa GrayAbstractThe bilingual advantage proposes that bilingual individuals have enhanced cognitive control compared to their monolingual counterparts. Bilingualism has also been shown to contribute to cognitive reserve by offsetting the behavioral presentation of brain injury or neural degeneration. However, this effect has not been closely examined in individuals with post-stroke or post-TBI aphasia. Because bilingualism has been suggested as a factor of cognitive reserve, it may provide protective mechan...
ConclusionRegardless of its rarity, it is evident that damage in the left SMA usually results in a clinical syndrome that clearly corresponds to aphasia. Interpreting this as an aphasia can aid in overcoming the limited idea of a “language zone” located in the perisylvian area of the left hemisphere, that was proposed over one century ago.
An elderly woman with h/o stroke and aphasia seemed different to her daughter, and was pointing all over her body as if in pain.They called 911.She had a history of PCI to the circumflex and also of severe mitral regurgitation, status post bioprosthetic valve replacement. Also a h/o LV aneurysm with thrombus, on anticoagulation, as well as a dual chamber pacemaker. On arrival, the BP was 60/30.Here is the initial ECG:There is atrial pacing and Right Bundle Branch Block (RBBB)There is STE in I and aVL, V5, V6, with reciprocal STD in II, III, aVFThere is appropriately discordant ST depression in V1-V3 (appropriate...
Discussion:GJB1 mutations form a clinical spectrum, including most patients with peripheral nerve involvement, those with both peripheral neuropathy and CNS involvement, and patients with CNS involvement only.
A 57-year-old man with atherosclerosis obliterans was admitted with sudden-onset sensory aphasia and right hemiparesis. Brain MRI revealed acute cerebral infarctions in the left temporal lobe and magnetic resonance angiography showed occlusion of the posterior branch of the left middle cerebral artery. Transesophageal echocardiography and ultrasonography respectively confirmed a patent foramen ovale and deep vein thrombosis in the bilateral femoral veins. Blood findings showed low protein S antigen, low protein S activity, and a missense mutation of the PROS 1 gene.
CONCLUSION: Despite widespread use of rTMS, high-quality evidence for its routine use for the treatment of stroke survivors is lacking. Further studies are required to establish differential roles of various protocols and long-term effects of rTMS in the stroke population. PMID: 31922207 [PubMed - as supplied by publisher]