0000000000076631
AUTHOR
Gail Robinson
Verbal suppression and strategy use: a role for the right lateral prefrontal cortex?
Verbal initiation, suppression and strategy generation/use are cognitive processes widely held to be supported by the frontal cortex. The Hayling Test was designed to tap these cognitive processes within the same sentence completion task. There are few studies specifically investigating the neural correlates of the Hayling Test but it has been primarily used to detect frontal lobe damage. This study investigates the components of the Hayling Test in a large sample of patients with unselected focal frontal (n = 60) and posterior (n = 30) lesions. Patients and controls (n = 40) matched for education, age and sex were administered the Hayling Test as well as background cognitive tests. The sta…
Impairments in proverb interpretation following focal frontal lobe lesions.
The proverb interpretation task (PIT) is often used in clinical settings to evaluate frontal “executive” dysfunction. However, only a relatively small number of studies have investigated the relationship between frontal lobe lesions and performance on the PIT. We compared 52 patients with unselected focal frontal lobe lesions with 52 closely matched healthy controls on a proverb interpretation task. Participants also completed a battery of neuropsychological tests, including a fluid intelligence task (Raven’s Advanced Progressive Matrices). Lesions were firstly analysed according to a standard left/right sub-division. Secondly, a finer-grained analysis compared the performance of patients w…
The differing roles of the frontal cortex in fluency tests
Fluency tasks have been widely used to tap the voluntary generation of responses. The anatomical correlates of fluency tasks and their sensitivity and specificity have been hotly debated. However, investigation of the cognitive processes involved in voluntary generation of responses and whether generation is supported by a common, general process (e.g. fluid intelligence) or specific cognitive processes underpinned by particular frontal regions has rarely been addressed. This study investigates a range of verbal and non-verbal fluency tasks in patients with unselected focal frontal ( n = 47) and posterior ( n = 20) lesions. Patients and controls ( n = 35) matched for education, age and s…
Limitations of the trail making test part-B in assessing frontal executive dysfunction.
AbstractPart B of the Trail Making Test (TMT-B) is one of the most widely used neuropsychological tests of “executive” function. A commonly held assumption is that the TMT-B can be used to detect frontal executive dysfunction. However, so far, research evidence has been limited and somewhat inconclusive. In this retrospective study, performance on the TMT-B of 55 patients with known focal frontal lesions, 27 patients with focal non-frontal lesions and 70 healthy controls was compared. Completion time and the number of errors made were examined. Patients with frontal and non-frontal lesions performed significantly worse than healthy controls for both completion time and the number of errors.…
Dynamic aphasia and the generation of language
Severely reduced propositional speech in the context of intact nominal language skills (i.e., repetition, naming, comprehension, and reading) is the hallmark of dynamic aphasia (Luria, 1970). Recent evidence suggests there may be different types of dynamic aphasia as some patients do not produce any response on verbal generation tasks, whilst others are able to perform normally on verbal genera- tion tasks. For example, Robinson and colleagues (Robinson, Blair, & Cipolotti, 1998; Robinson, Shallice, & Cipolotti, 2004) reported two dynamic aphasics who failed to produce a verbal response when many verbal response options were activated by a stimulus, but not when a dominant response was avai…
A failure of high level verbal response selection in progressive dynamic aphasia.
Different theoretical interpretations have been offered in order to account for a specific language impairment termed dynamic aphasia. We report a patient (CH) who presented with a dynamic aphasia in the context of nonfluent progressive aphasia. CH had the hallmark of reduced spontaneous speech in the context of preserved naming, reading, and single word repetition and comprehension. Articulatory and grammatical difficulties were also present. CH had a very severe verbal generation impairment despite being able to describe pictorial scenes and action sequences well. In the experimental investigations CH was severely impaired in word, phrase, and sentence generation tasks when many competing…
The effect of age on cognitive performance of frontal patients
Age is known to affect prefrontal brain structure and executive functioning in healthy older adults, patients with neurodegenerative conditions and TBI. Yet, no studies appear to have systematically investigated the effect of age on cognitive performance in patients with focal lesions. We investigated the effect of age on the cognitive performance of a large sample of tumour and stroke patients with focal unilateral, frontal (n=68), or non-frontal lesions (n=45) and healthy controls (n=52). We retrospectively reviewed their cross sectional cognitive and imaging data. In our frontal patients, age significantly predicted the magnitude of their impairment on two executive tests (Raven's Advanc…
Conceptual proposition selection and the LIFG: neuropsychological evidence from a focal frontal group.
Much debate surrounds the role of the left inferior frontal gyrus (LIFG). Evidence from lesion and neuroimaging studies suggests the LIFG supports a selection mechanism used in single word generation. Single case studies of dynamic aphasic patients with LIFG damage concur with this and extend the finding to selection of sentences at the conceptual preparation stage of language generation. A neuropsychological group with unselected focal frontal and non-frontal lesions is assessed on a sentence generation task that varied the number of possible conceptual propositions available for selection. Frontal patients with LIFG damage when compared to Frontal patients without LIFG damage and Posterio…
“My Mind Is Doing It All”
Objective: To study whether pressure of speech in jargon aphasia arises out of disturbances to core language or executive processes, or at the intersection of conceptual preparation. Background: Conceptual preparation mechanisms for speech have not been well studied. Several mechanisms have been proposed for jargon aphasia, a fluent, well-articulated, logorrheic propositional speech that is almost incomprehensible. Methods: We studied the vast quantity of jargon speech produced by patient J.A., who had suffered an infarct after the clipping of a middle cerebral artery aneurysm. We gave J.A. baseline cognitive tests and experimental word-and sentencegeneration tasks that we had designed for …