Improvement of verbal fluency in patients with diffuse brain injury over time

Abstract

BackgroundDiffuse axonal injury (DAI), a common cause of neurological sequelae in patients with traumatic brain injury (TBI), is considered one of the most prevalent forms of primary neuronal injury in patients with severe TBI. Cognitive deficits induced by DAI can persist over time, especially following moderate or severe injuries. The aim of the present study was to compare verbal fluency (VF) performance at 6 and 12 months after the trauma in a same group of patients with DAI.MethodsEighteen patients with moderate to severe DAI and 17 healthy volunteers were enrolled. All DAI participants had sustained a TBI at least 6 months prior to the start of the study, were between 18 and 50 years of age, and had at least 4 years of education. The VF test was administered within an extensive neuropsychological test battery. We evaluated the same patients at 6 months (DAI1 group) and 12 months (DAI2 group) and compared the results of neuropsychological tests with a control group of healthy volunteers who were matched to patients for sex, age, and educational level.ResultsIn comparison to controls, the DAI1 group produced significantly fewer words. The DAI2 group produced significantly more semantic words than DAI1 (P<0.05) and demonstrated a trend towards the production of more clusters for letter A (P=0.09) and total words generated in a phonemic test (P=0.09). No significant differences were observed between DAI2 and the control group in the total number of words generated in phonetic FAS or semantic fluency scores.ConclusionThe present findings may be useful in the construction of a management plan for long-term TBI rehabilitation that considers the trauma of each patient. Further, our results suggest the VF test is a suitable instrument for the assessment of cognitive difficulties following TBI.

New ways to analyze word generation performance in brain injury: A systematic review and meta-analysis of additional performance measures

“…Concerning the research designs and research topics, the majority of studies (18 studies) compared word generation performance of a clinical group either to that of a control group or to normative data, or to another (clinical) group (Bittner & Crowe, 2006;Cralidis & Lundgren, 2014;Crawford et al, 2007;Crowe, 1996 Zakzanis et al, 2011Zakzanis et al, , 2013Zaninotto et al, 2014). In two studies, word generation performance is examined in relation to another performance measure (e.g., cognitive skills, naming) within a group of participants (Bittner & Crowe, 2007;Haggard, Cockburn, Cock, Fordham, & Wade, 2000).…”

“…Out of the 20 studies including at least one additional measure, 14 studies reported a sufficient number of data points in order to calculate effect sizes. Due to a lack of sufficient data we could not include the additional measures word frequency and classification of word class in our effect size Gruen et al, 1990;Johnson et al, 2012;Kavé et al, 2011;Kessler et al, 1997;Raskin & Rearick, 1996;Sperinck & Picciotto, 1999;Velázquez-Cardoso et al, 2014;Zakzanis et al, 2011Zakzanis et al, , 2013Zaninotto et al, 2014 .55…”

“…Proportion of errors and analyses of error types Number of repetitions, number of rule break errors, number of nonitems (like interjections), set-loss errors Cralidis & Lundgren, 2014;Crowe, 1996;Crowe & Crowe, 2013;Curtis et al, 2008;Haggard et al, 2000;Kessler et al, 1997;McDonald et al, 2010;Raskin & Rearick, 1996;Zakzanis et al, 2013;Zaninotto et al, 2014 . calculation.…”

“…Based on the above findings, the following paragraphs will present more detailed information for the individual performance measures, give more specific definitions of all identified variables, and outline their underlying theoretical assumptions. We mainly focus on those studies that explicitly discuss the strengths or weaknesses of additional performance measures and hence their diagnostic value (i.e., Crowe, 1996;Curtis et al, 2008;Johnson et al, 2012;Kavé et al, 2011;Raskin & Rearick, 1996;Silverberg et al, 2008;Zakzanis et al, 2011Zakzanis et al, , 2013Zaninotto et al, 2014;Velázquez-Cardoso et al, 2014). The conclusions drawn by the authors of these studies paint a rather heterogeneous picture, regardless of whether the additional measures outperform the traditional measure of correct production or not.…”

“…Clustering (i.e., the identification and generation of words within lexical or semantic subcategories: for example, farm animals or birds within an animal naming task) is described as a component "that reflects the semantic organization of memory stores" (Kavé et al, 2011, p. 359) and that tends to be automatic and mediated by the temporal lobe. In contrast, switching (i.e., switching to another subcategory once one subcategory is exhausted) is characterized as an executive component that tends to be strategic and mediated by the frontal lobe (Cralidis & Lundgren, 2014;Johnson et al, 2012;Kavé et al, 2011;Raskin & Rearick, 1996;Sperinck & Picciotto, 1999;Zakzanis et al, 2011Zakzanis et al, , 2013Zaninotto et al, 2014).…”