Verbal planning in a case of ‘Dynamic Aphasia’: An impairment at the level of macroplanning

Abstract

Patients with 'dynamic aphasia' exhibit reduced spontaneous speech despite well preserved basic language functions. This disorder may allow insights into the conceptual preparation of messages. Various cognitive approaches have located the patients' impairment at the level of preverbal message generation, including verbal planning, loss of inhibition of lexical concepts, and, most recently, generation of sequences of novel thoughts. We report the case of HK who presented with dynamic aphasia. The study had two goals: first, as HK was assessed over a longer period of time, changes in his performances could be documented which were relevant for the interpretation of the underlying disorder. The present study is the first to document changes across time and improvements of some of the skills involved in language production. Second, further investigations were carried out to clarify HK's underlying deficits. He was unimpaired on a number of 'verbal planning' tasks which argues for the preservation of those specific processes of verbal planning which Levelt (1989) termed 'microplanning'. It is suggested that HK's performance may be best described as an impairment at the level of 'macroplanning'. The deficit may lie in the generation of novel thoughts though minor modifications of this recent approach are being suggested.

Luria’s classification of aphasias and its theoretical basis

“…Other researchers also confirm the presence of difficulties of verbal planning in the syndrome of dynamic aphasia (Bormann, Wallesch, & Blanken, 2008;De Lacy Costello & Warrington, 1989;Robinson, Blair, & Cipolotti, 1998;Robinson, Shallice, & Cipolotti, 2006). The extent to which utterance planning is disrupted may vary: in severe cases, a patient cannot and does not attempt to initiate speech; in milder forms, the impairment may be almost undetectable to an outside observer, and only manifest itself when there is a need to plan a relatively extensive narrative.…”

Propositional speech in unselected stroke: The effect of genre and external support

“…Another process crucial for propositional speech was suggested by investigation of patient KAS, who was impaired on discourse level generation tests, with intact word/sentence level generation (Robinson, Shallice, & Cipolotti, 2006; see also Bormann, Wallesch et al, 2008). KAS presented with dynamic aphasia in the context of progressive supranuclear palsy (PSP) and atrophy involving subcortical and bilateral frontal areas.…”

“…Dynamic aphasia is a distinct language disorder characterised by reduced propositional speech despite well-preserved core language skills (i.e., repetition, reading, naming, comprehension; Luria, 1970Luria, , 1973. This disorder has been documented in both neurodegenerative conditions (e.g., Esmonde, Giles, Xuereb, & Hodges, 1996) and focal lesions (e.g., Bormann, Wallesch, & Blanken, 2008;Costello & Warrington, 1989;Raymer, Rowland, Haley, & Crosson, 2002), including individuals following stroke (e.g., Crescentini, Lunardelli, Mussoni, Zadini, & Shallice, 2008;Gold et al, 1997). Several accounts for dynamic aphasia have been proposed that suggest the disorder is due to a breakdown in the process of translating internal speech into overt speech (Luria, 1970(Luria, , 1973, a failure in verbal planning (Costello & Warrington, 1989), an inefficient semantic search strategy (Gold et al, 1997), an inability to generate verbal and non-verbal responses (Raymer et al, 2002), and an inability to select one idea from amongst multiple competing ideas (Robinson, Blair, & Cipolotti, 1998;Robinson, Shallice, & Cipolotti, 2005).…”

“…At the same time, the need to organise steps may place greater demands on sequencing. To elicit procedural speech, the speaker may be asked to describe the steps involved in a behavioural sequence such as buying groceries (Hartley & Jensen, 1991) or making a cup of tea (Bormann, Wallesch et al, 2008;Legg & Sonnenberg, 1998). A second way to elicit procedural speech is with static visually presented material.…”

“…Specific investigations of propositional speech have been conducted in selected stroke populations (e.g., patient with left middle cerebral artery stroke and dynamic aphasia, Bormann, Wallesch, & Blanken, 2008; right hemisphere stroke, Sherratt & Bryan, 2012). Thus far, there has been no specific study examining propositional speech generation in an unselected sample of stroke patients, possibly due to the subtle nature of deficits and/or the fact that nominal language can be well-preserved as it is in dynamic aphasia (discussed below).…”