Reduced phonological similarity effects in patients with damage to the cerebellum

Abstract

Ten cerebellar patients were compared to ten control subjects on a verbal working memory task in which the phonological similarity of the words to be remembered and their modality of presentation were manipulated. Cerebellar patients demonstrated a reduction of the phonological similarity effect relative to controls. Further, this reduction did not depend systematically upon the presentation modality. These results first document that qualitative differences in verbal working memory may be observed following cerebellar damage, indicating altered cognitive processing, even though behavioral output as measured by the digit span may be within normal limits. However, the results also present problems for the hypothesis that the cerebellar role is specifically associated with articulatory rehearsal as conceptualized in the Baddeley-Hitch model of working memory. Keywordscerebellum; verbal working memory; speech perception; language; cognition; short-term memory; dysarthria; aphasia Researchers in cognitive neuroscience have in many cases looked to converging data from multiple methodologies when investigating a cognitive process of interest. The complementary perspectives of functional neuroimaging and cognitive neuropsychology are often employed in this regard; a strong case can be made for the involvement of a brain region in a given cognitive process when it is both metabolically active when healthy participants engage in the cognitive process, and when damage to this region disrupts the same cognitive process. Although the precise nature of this involvement may prove elusive to characterize, the brain region comes to be regarded as an essential component of the system in question. When the two methodologies of neuroimaging and neuropsychology do not converge, however, even the most basic question of whether a given region is involved in a cognitive process is difficult to address.One issue that must be kept in mind when making comparisons between data from neuroimaging and data from neuropsychology is that the two methods provide very different kinds of evidence about cognition. Neuroimaging studies have the potential to document qualitative aspects of cognitive processing that may not be evident from the behavioral outcome. In contrast, neuropsychological data -particularly that from standardized batteries that examine for gross impairment across a wide range of cognitive tasks -sometimes do not NIH-PA Author ManuscriptNIH-PA Author Manuscript NIH-PA Author Manuscript allow for such an observation. Identical behavioral outcomes may become falsely equated with identical cognitive processes, when this most certainly is not always the case. 1 Neuropsychological studies must be designed such that the relevant qualitative as well as quantitative differences in a cognitive process may be observed.A relative lack of convergence in the neuroimaging and neuropsychological literatures was a part of the motivation for the current study, which investigated the verbal working memory abilities of patients with damage...

Meta-analytic connectivity and behavioral parcellation of the human cerebellum

“…Lobules contributing to Cluster 4 are heavily involved in motor tasks, but a clear over-representation in the cognition domain and significant activation with the go/no-go task indicate this region may contribute to generating time-based expectancies of sensory information (Ghajar and Ivry 2009). Cerebellar involvement in language processing and verbal working memory has been clinically demonstrated through dysfunction in language acquisition and dyslexia (Nicolson et al, 2001), and impairment of working memory (Justus et al, 2005). Furthermore, Ravizza et al (2006), suggests that the cerebellum is involved in phonological encoding and in strengthening memory traces.…”

Consensus Paper: Language and the Cerebellum: an Ongoing Enigma

“…Evidence from studies of patients with cerebellar infarctions [80–86], spino-cerebellar ataxia [83, 87], and cerebellar tumors [83, 84, 88–97] indicate mild to moderate VWM deficits relative to healthy, well-matched controls. In most studies, VWM has been assessed by measuring individual tests within a larger, broader neuropsycho-logical assessment battery.…”

Language and Social Communication in Children with Cerebellar Dysgenesis

“…clitic pronouns) and, in the case of verbs, substitution of tensed inflections with infinitive endings. These findings have been interpreted in at least 4 different ways: as a problem with online coupling of stem forms and morphological markings in verbal working memory [4,5] ; as a phonological planning deficit which may impact on the selection of unstressed function words and word stems [6,7] ; as a reduced access to morphophonemic or morphosyntactic representations [8,9] , and as an instance of an inability of the damaged cerebellum to maintain a smooth and fine-tuned organization of the different components of language processing [10] . However, besides morphosyntactic errors, adults with acquired cerebellar damage have also evidenced selective semantic deficits, such as verb-to-noun or antonym-to- noun generation [11][12][13] .…”