Jeffrey P. Johnson

Dural closure with laser tissue welding

This study investigates the use of tissue-soldering techniques to substitute or reinforce traditional suture closure of dural incisions. Fresh human cadaveric dura was incised and subsequently closed by use of three techniques: (1) conventional interrupted suture with 4-0 silk (n = 25), (2) laser solder reinforced suture closure (n = 25), and (3) laser solder closure alone (n = 25). Anastomosis tensile strength and hydrostatic leak pressures were measured. Dural repair was also performed in 15 live Lewis rats. Dural closure was accomplished with 9-0 Prolene sutures (n = 5), laser-reinforced suture closure (n = 5), and laser solder closure alone (n = 5). Histologic examination of the closure immediately after soldering and 2 weeks later was performed. Suture closure alone had the lowest leak pressure, 9.4 +/- 1.7 mm Hg, and an intermediate break point, 13.3 +/- 2.1 Kgf/cm2. Measurements with laser solder alone revealed a mean leak pressure of 26.2 +/- 3.7 mm Hg and a break point of 4.6 +/- 1.4 Kgf/cm2. Solder-reinforced suture closure leak pressure measured 64.0 +/- 6.7 mm Hg and 21.4 +/- 2.4 Kgf/cm2. There was a statistically significant increase in leak pressure and tensile strength in the closures performed with laser weld reinforcement of traditional suture technique (p = 0.0001). Dural closure with laser tissue welding alone provided an immediate leak-free closure, but with poor tensile strength. Histologic examination of welded dura and underlying brain tissue showed no evidence of thermal injury in four of five animals studied. Laser welding may significantly decrease the incidence of cerebrospinal fluid leak after dural closure. In addition, laser tissue welding also makes dural closure possible where space constraints make traditional suture closure difficult.

Does Naming Therapy Make Ordering in a Restaurant Easier? Dynamics of Co-Occurring Change in Cognitive-Linguistic and Functional Communication Skills in Aphasia

Purpose This study was conducted to investigate the static and dynamic relationships between impairment-level cognitive-linguistic abilities and activity-level functional communication skills in persons with aphasia (PWA). Method In Experiment 1, a battery of standardized assessments was administered to a group of PWA (N = 72) to examine associations between cognitive-linguistic ability and functional communication at a single time point. In Experiment 2, impairment-based treatment was administered to a subset of PWA from Experiment 1 (n = 39) in order to examine associations between change in cognitive-linguistic ability and change in function and associations at a single time point. Results In both experiments, numerous significant associations were found between scores on tests of cognitive-linguistic ability and a test of functional communication at a single time point. In Experiment 2, significant treatment-induced gains were seen on both types of measures in participants with more severe aphasia, yet cognitive-linguistic change scores were not significantly correlated with functional communication change scores. Conclusions At a single time point, cognitive-linguistic and functional communication abilities are associated in PWA. However, although changes on standardized assessments reflecting improvements in both types of skills can occur following an impairment-based therapy, these changes may not be significantly associated with each other.

Typicality-based semantic treatment for anomia results in multiple levels of generalisation

ABSTRACT This study investigated the effects of typicality-based semantic feature analysis (SFA) treatment on generalisation across three levels: untrained related items, semantic/phonological processing tasks, and measures of global language function. Using a single-subject design with group-level analyses, 27 persons with aphasia (PWA) received typicality-based SFA to improve their naming of atypical and/or typical exemplars. Progress on trained, untrained, and monitored items was measured weekly. Pre- and post-treatment assessments were administered to evaluate semantic/phonological processing and overall language ability. Ten PWA served as controls. For the treatment participants, the likelihood of naming trained items accurately was significantly higher than for monitored items over time. When features of atypical items were trained, the likelihood of naming untrained typical items accurately was significantly higher than for untrained atypical items over time. Significant gains were observed on semantic/phonological processing tasks and standardised assessments after therapy. Different patterns of near and far transfer were seen across treatment response groups. Performance was also compared between responders and controls. Responders demonstrated significantly more improvement on a semantic processing task than controls, but no other significant change score differences were found between groups. In addition to positive treatment effects, typicality-based SFA naming therapy resulted in generalisation across multiple levels.

Multi-step treatment for acquired alexia and agraphia (Part I): efficacy, generalisation, and identification of beneficial treatment steps

ABSTRACT Reading and writing impairments are common in individuals with post-stroke aphasia. Treatment typically aims to improve the function of one of these modalities by strengthening aspects of either lexical or sublexical processing. In the present study, eight adults with acquired alexia and agraphia were administered a comprehensive treatment targeting specific lexical and sublexical processes underlying reading and/or writing. Two participants were trained in reading and six were trained in writing. Throughout treatment, reading and writing accuracy were monitored for trained items, as well as untrained but orthographically and semantically related items. Linear mixed effects models indicated that the most substantial gains were made on trained items in the trained modality; generalisation to trained items in the untrained modality and untrained but related items in both modalities was also observed. Participants improved significantly on a subset of treatment steps intended to address lexical access and representations, sublexical conversion mechanisms, and the graphemic and/or phonological buffer processes in both modalities. These results demonstrate the efficacy of a novel, comprehensive treatment protocol and suggest that targeting multiple reading and writing processes in conjunction may facilitate widespread generalisation.

Randomized controlled trial of supplemental augmentative and alternative communication versus voice rest alone after phonomicrosurgery

Objective This randomized trial investigated voice rest and supplemental text-to-speech communication versus voice rest alone on visual analog scale measures of communication effectiveness and magnitude of voice use. Study Design Randomized clinical trial. Setting Multicenter outpatient voice clinics. Subjects Thirty-seven patients undergoing phonomicrosurgery. Methods Patients undergoing phonomicrosurgery were randomized to voice rest and supplemental text-to-speech communication or voice rest alone. The primary outcome measure was the impact of voice rest on ability to communicate effectively over a 7-day period. Pre- and postoperative magnitude of voice use was also measured as an observational outcome. Results Patients randomized to voice rest and supplemental text-to-speech communication reported higher median communication effectiveness on each postoperative day compared to those randomized to voice rest alone, with significantly higher median communication effectiveness on postoperative days 3 (P = .03) and 5 (P = .01). Magnitude of voice use did not differ on any preoperative (P > .05) or postoperative day (P > .05), nor did patients significantly decrease voice use as the surgery date approached (P > .05). However, there was a significant reduction in median voice use pre- to postoperatively across patients (P < .001) with median voice use ranging from 0 to 3 throughout the postoperative week. Conclusion Supplemental text-to-speech communication increased patient-perceived communication effectiveness on postoperative days 3 and 5 over voice rest alone. With the prevalence of smartphones and the widespread use of text messaging, supplemental text-to-speech communication may provide an accessible and cost-effective communication option for patients on vocal restrictions.

Preserving the flexibility of single-subject experimental design—a commentary on “Optimising the design of intervention studies: critiques and ways forward”

Howard, Best, and Nickels (2014) indicate that there are fundamental flaws in the construction, analysis, and interpretation of single-case experimental design and offer recommendations for avoiding such issues. This discussion is presented in the context of two approaches to single-subject research, but these approaches are neither mutually exclusive nor described with complete precision. In asserting that single-case research occurs according to one or the other of the two presented frameworks, the authors overlook the fact that many of their concerns can be circumvented by researchers on a case-by-case basis, by way of decisions and strategies that are unaccounted for in the approaches presented. The flexibility to navigate threats to the validity of research using theoretically sound, but creative and unique strategies, is a significant advantage of singlesubject experimental design. Strict adherence to a limited set of one-size-fits-all design recommendations—in terms of item selection, frequency of assessment, duration of treatment, and data analysis—would strip away much of that flexibility. The authors raise concerns about the use of small-n stimuli sets and attribute their use, among other things, to frequent probing that occurs in single-case research. While we agree that a larger-n stimuli set is ideal from a statistical perspective, there are practical reasons, other than probing frequency, that require researchers to opt for a smaller set. For example, with a larger set, the issue of limited dosage arises; that is, as the set of treated items increases, it becomes more difficult to ensure that subjects are sufficiently exposed to all items throughout the course of treatment. Howard et al. also express concern over misinterpretation of the results of studies that use small-n sets when visual inspection is the primary mode of analysis and argue that small-n sets limit the validity of conclusions drawn “about the shape of change during the course of therapy” (p. 532). We agree with the premise that visual analysis alone is no longer the ideal analysis technique for singlesubject research, but we would argue that it is fairly easy and reasonable to calculate the slope of the treatment phase when one is studying change in performance as a function of treatment. Howard et al. ultimately advocate for a stimuli set of 30 or more items (p. 533, 545, footnote 8), which may or may not be practical, depending on the area of inquiry and the nature of the study. In fact, this guideline is feasible only because they also recommend “sparse probing (e.g., preand post-therapy or with one/two within-therapy probes)” (p. 544). However, frequent probing can be a useful component of single-subject experimental design when untreated items are included in order to examine the presence and progression of generalization. Further, a single post-therapy probe would not allow the investigator to examine whether any gains shown immediately after treatment were

Investigating the relationship between language and cognition in persons with aphasia as a function of semantic-based naming therapy

Background: Pretreatment cognitive skills influence language treatment outcomes in persons with aphasia (PWA; Dignam et al., 2017), yet what specific cognitive subskills are important for specific treatments remains unclear. Furthermore, few studies have investigated whether PWAs’ cognitive abilities improve after language therapy (Des Roches et al., 2015). Aims: (1) What cognitive subskills predict semantic-based naming therapy gains, maintenance and generalization (Gilmore et al., 2018, under revision)? (2) Do cognitive subskills improve as a function of semantic-based naming therapy?

Multi-step treatment for acquired alexia and agraphia (part II): a dual-route error scoring system

ABSTRACT Dual-route neuropsychological models posit two distinct but interrelated pathways for reading and writing: the lexical and the sublexical. Individuals with reading/writing deficits often rely on the combined power of the integrated system to perform print-processing tasks. The resultant errors reflect varying degrees of lexical and sublexical accuracy in a single production; however, no system presently exists to analyze errors robustly in both routes. The goal of this project was to develop a system that simultaneously, quantitatively, and qualitatively captures changes in lexical and sublexical errors following treatment. Errors are evaluated hierarchically in both routes according to proximity to a target. This dual-route error scoring (DRES) system was developed using data from a novel treatment study for eight patients with acquired alexia/agraphia; a computerised version of the system was also developed (ADRES). Repeated-measures multivariate analyses of variance and post hoc analyses revealed significant dual-route treatment effects. Qualitative analyses revealed unique patterns of change across participants, reflecting the benefits of error evaluation beyond a binary correct/incorrect judgment. Finally, categorical error shifts were observed via group-level analysis. The results of this study indicate that treatment-induced evolution of reading/writing can be meaningfully and comprehensively represented by this novel scoring system.

Poster 49 Laser Welding of Dural Closures: A New Technique

This study concerns the gross and histologic effects of scalpel, electrocautery, voltage-modulated electrocautery (VME), and carbon dioxide laser (CO2) incisions on the mucosal tissue of swine. There are numerous tissue studies in the literature that compare the CO 2 laser with the scalpel and electrocantery. However, a gross and histologic comparison involving oral mucosal tissue has not been reported. We used a swine model of both the tongue and buccal mucosa to help compare scalpel, electrocautery, VME, and CO 2 laser in an effort to assess their value in oral surgery. Tissue sampling of both tongue and buccal mucosa incisions and excisions were histologically examined at 0, 3, 7, 14, 28, and 42 days postoperatively to evaluate tissue damage and wound healing induced by the four instruments. The instruments were also evaluated for performance and ease of use. On subjective evaluation of ease of use, the VME scored highest with a mean + SD of 3.4 _+ 0.7 on a 0 to 4 scale followed by the CO s laser (3.2 + 0.7). Time of incisions and excisions, measured in seconds, was fastest with the scalpel (9.1 + 6.4, 29.6 + 13.4) followed by electrocautery (8.1 + 4.7, 32.1 + 15.0). The amount of bleeding as evaluated on a 0 to 4 scale was least (incisions, excisions) for the electrocautery (0.1 + 0.2, 0.2 + 0.5) and CO s laser (0.1 + 0.3, 0.2 _+ 0.5). Histologic damage, as expected, was least with a scalpel. The extent of epithelial damage lateral to the wound edge (in millimeters) was 0.08 _+ 0.04 followed by VME (1.1 + 0.4). The extent of collagen denaturation was also least with the scalpel (0.02 + 0.02), followed by VME (0.3 +_ 0.1). All four instruments displayed intact epithelium by 2 weeks and collagen formation peaked at 4 weeks for instruments except the VME, where collagen formation was still prevalent by week 6. The VME and the CO s laser provided the best combination of ease of use, hemostasis, and tissue injury among the instruments compared. Use of VME was less time consuming than use of the COz laser, but it also resulted in significantly more collagen formation in the later weeks of the study, which suggests that wound healing may be delayed. Poster 48