Semantic access dysphasia resulting from left temporal lobe tumours

Abstract

Unlike semantic degradation disorders, the mechanisms and the anatomical underpinnings of semantic access disorders are still unclear. We report the results of a case series study on the effects of temporal lobe gliomas on semantic access abilities of a group of 20 patients. Patients were tested 1–2 days before and 4–6 days after the removal of the tumour. Their semantic access skills were assessed with two spoken word-to-picture matching tasks, which aimed to separately control for rate of presentation, consistency and serial position effects (Experiment 1) and for word frequency and semantic distance effects (Experiment 2). These variables have been held to be critical in characterizing access in contrast to degraded-store semantic deficits, with access deficits characterized by inconsistency of response, better performance with slower presentation rates and with semantically distant stimuli, in the absence of frequency effects. Degradation deficits show the opposite pattern. Our results showed that low-grade slowly growing tumours tend not to produce signs of access problems. However, high-grade tumours especially within the left hemisphere consistently produce strong semantic deficits of a clear access type: response inconsistency and strong semantic distance effects in the absence of word frequency effects were detected. However, effects of presentation rate and serial position were very weak, suggesting non-refractory behaviour in the tumour patients tested. This evidence, together with the results of lesion overlapping, suggests the presence of a type of non-refractory semantic access deficit. We suggest that this deficit could be caused by the disconnection of posterior temporal lexical input areas from semantic system.

The Differential Contributions of pFC and Temporo-parietal Cortex to Multimodal Semantic Control: Exploring Refractory Effects in Semantic Aphasia

“…The current study also confirms that lesion location affects the likelihood of refractory deficits, with pFC+ patients showing deterioration in accuracy, whereas TPonly patients maintain performance across cycles. A difference between these patient groups has been predicted by previous research (Campanella et al, 2009;Schnur et al, 2009), although the explanation given for refractoriness is not compatible with the current findings of multimodal refractory effects in pFC+ patients. Indeed, the difference between pFC+ and TP-only patients is perhaps surprising, as several lines of research indicate that both left pFC and posterior temporal/inferior parietal regions make a critical contribution to multimodal semantic control.…”

What we talk about when we talk about access deficits

“…JM [21]; MH, RS b [22]; BM [23]; 7/10 pre-and 6/8 postsurgery glioma patients [24] c spoken-to-written word matching MED [16]; AZ [25,26] picture naming 4/4 SA patients [9] a ; BM [23]; FAS [27]; 18 aphasic patients [28] d,e reading VYG [29] matching non-verbal sounds to pictures or words AZ, BBB [30] performance inconsistency spoken word-to-picture matching AA [12]; HEC [13]; VER [14]; YOT [15]; MED [16]; AZ [18]; UM-103 [19] JM [21]; MH, RS b [22]; 9/9 pre-and 5/6 postsurgery glioma patients [24] c spoken-to-written word matching AZ [17]; MED [16] picture-to-picture matching AZ [18] picture naming FAS [27] word reading VEM [31] matching non-verbal sounds to pictures or words AZ, BBB [30] negative serial position effect spoken word-to-picture matching AA [12]; HEC [13]; AZ [17,32]; JM [21]; RS b [22]; VER [14]; IRQ [33]; 2/9 pre-and 2/7 postsurgery glioma patients [24] c spoken-to-written word matching AZ [17,25,26,32]; MED [16]; IRQ [33]; JM [34] picture naming FAS …”

“…IRQ [33]; AZ [32]; 9/10 pre-and 7/8 postsurgery glioma patients [24] c spoken-to-written word matching AZ [18,25,26,32,35]; MED [16]; IRQ [33]; FBI, NBC [36] naming pairs of pictures 2/2 semantic short-term memory deficit patients [37]; JHM [38] miscueing effects in picture naming 3/3 aphasic patients [39]; 5/6 SA patients [40] a ; seven SA patients [41,42] a,e matching non-verbal sounds to pictures or words AZ, BBB [30] selecting an object to complete a common task In addition to generally inconsistent performance, individuals with access deficits exhibit declining performance over repeated presentations of a stimulus, typically called a negative serial position effect (where 'serial position' refers to repetition of the same item, unlike in serial order recall tasks where it refers to position of different items). In the simplest studies, trials were presented in a ( pseudo-)random order and repeated multiple times.…”

Going beyond Inferior Prefrontal Involvement in Semantic Control: Evidence for the Additional Contribution of Dorsal Angular Gyrus and Posterior Middle Temporal Cortex

“…Patients with left pFC lesions have less fluent language production (Berthier, 2001), and they also have greater difficulty than temporoparietal cases in inhibiting previously relevant semantic information-namely, they exhibit "refractory" semantic behavior, that is, declining accuracy in "cyclical" word-picture matching tasks that present a set of semantically related items repeatedly, leading to a build-up of competition between previous and current targets (Gardner et al, 2012;Campanella, Mondani, Skrap, & Shallice, 2009;Jefferies, Baker, Doran, & Lambon Ralph, 2007). Similarly, pMTG and dAG/IPS may play distinct roles in the regulation of semantic processing, although these regions do not easily dissociate in studies of brain-injured patients.…”