Visual Distraction: An Altered Aiming Spatial Response in Dementia

Background/Aims: Healthy individuals demonstrate leftward bias on visuospatial tasks such as line bisection, which has been attributed to right brain dominance. We investigated whether this asymmetry occurred in patients with probable dementia of the Alzheimer type (pAD) which is associated with neurodegenerative changes affecting temporoparietal regions. Methods: Subjects with pAD and matched controls performed a line bisection task in near and far space under conditions of no distraction, left-sided visual distraction and right-sided visual distraction. Results: Participants with pAD manifested different motor-preparatory ‘aiming’ spatial bias than matched controls. There were significantly greater rightward ‘aiming’ motor-intentional errors both without distraction and with right-sided distraction. Conclusion: ‘Aiming’ motor-preparatory brain activity may be induced by distraction in pAD subjects as compared to typical visual-motor function in controls

Assessment of Neglect Dyslexia with Functional Materials

Spatial neglect is a neurocognitive disorder, affecting perception, representation, and/or motor planning. Neglect dyslexia in spatial neglect after right hemisphere damage (RHD) may co-occur with, or be dissociated from, other spatial neglect signs (Arduino, Daini, & Silveri, 2005; Lee et al., 2009; Vallar, Burani, & Arduino, 2010). Previous neglect dyslexia research focused on word-level stimuli and reading errors, primarily identifying letter omissions and substitutions to the left of the word midpoint (Ellis, Flude, & Young, 1987). However, functional materials may be more challenging to read (greater spatial extent of sentences and paragraphs, versus words). Although experimental studies that focus on reading at the single-word level may ask interesting theoretical questions regarding the sources of errors in the reading stages and systems, it is not often in the real-world that people read single words in isolation. We hypothesized that assessment materials with ecological validity such as reading a menu and reading an article would be more reflective of the degree to which reading errors and neglect dyslexia was detected in individuals with RHD than assessments that contained only single words or short phrases, which are rarely read in isolation in everyday life

Translational Treatment of Aphasia Combining Neuromodulationand Behavioral Intervention for Lexical Retrieval: Implications from a Single Case Study

BackgroundTranscranial direct current stimulation (tDCS), a non-invasive method of brain stimulation, is an adjunctive research-therapy for aphasia. The concept supporting translational application of tDCS is that brain plasticity, facilitated by language intervention, can be enhanced by non-invasive brain stimulation. This study combined tDCS with an ecologically-focused behavioral approach that involved training nouns and verbs in sentences. MethodParticipant: A 43-year-old, right-handed male with fluent-anomic aphasia who sustained a single-left-hemisphere-temporal-parietal stroke was recruited. Treatment: Instrumentation included the Soterix Medical 1x1 Device. Anodal tDCS was applied over Broca’s area. Behavioral materials included: sentence production, naming in the sentence context, and implementation of a social-conversational-discourse treatment.Design and Procedures: The independent variable of this crossover case-study was tDCS, and the dependent variables were language and quality-of-life measures. In each session the subject received language treatment with the first twenty minutes additionally including tDCS. ResultsPerformance in naming nouns and verbs in single words and sentences were obtained. Verb production in the sentence context increased after active anodal tDCS and speech-language treatment. ConclusionAphasia treatment that involves naming in the sentence context in conjunction with translational application of tDCS may be a promising approach for language-recovery post stroke

Treatment of Aphasia Combining Neuromodulation and Behavioral Intervention: Taking an Impairment and Functional Approach

Background Current treatment of aphasia involves behavioral speech-language intervention, yet many people continue to have significant communication impairments even after a course of speech-language treatment. Therefore, there is a continued need to develop new treatments to address the persistent speech and language deficits of stroke survivors. One such development that is quickly gaining traction as an adjunctive therapy to traditional speech and language treatment is transcranial direct current stimulation (tDCS), a non-invasive procedure that involves the stimulation of the cerebral cortex by way of a weak electrical current (Nitsche et al., 2003; Iyer et al., 2005). The mechanism supporting the use of tDCS is that learning, facilitated by speech-language intervention, can be enhanced by brain plasticity. The underlying biological mechanisms associated with neuroplasticity, and thereby the improvement of linguistic functioning in the recovering brain is still under investigation-- including among therapists working behaviorally with stroke survivors with aphasia (Galletta et al., 2011). This study focused on combining neuromodulation with an efficacious and ecologically-valid behavioral therapy. No tDCS studies to date have utilized a behavioral treatment approach that includes naming and discourse, yet in real life communication, naming occurs more often in the discourse context than in single words in isolation. As well, no previous study has included the production of nouns and verbs in sentences as outcome measures. Method Participant: A 43 year-old, right-handed stroke survivor who sustained a left hemisphere stroke was recruited. Baseline testing indicated a word retrieval deficit for nouns and verbs. Treatment: Instrumentation included the Soterix Medical 1x1 tDCS Device designed to be used for research to administer tDCS. Behavioral treatment materials included sentence production training (Helm-Estabrooks and Nicholas, 2001), naming in the sentence context (based on Raymer and Kohen, 2006), and implementation of a social, conversational treatment (based on Simmons-Mackie et al. 2001). See example of treatment schedule (Figure 1) below. These materials were created and piloted prior to this study (Galletta et al., 2013). Figure 1: Schematic of treatment schedule. Behavioral treatment order alternated each session. Design and Procedures: The independent variable of this double-blind crossover study was tDCS intervention, and the dependent variables were speech and language abilities, and health-related quality-of-life measures. The subject received sixty-minutes of speech-language treatment with the first twenty minutes additionally including tDCS. Results Baseline measures of naming nouns and verbs in single words, and sentences, were obtained. While there was no improvement in production of nouns or verbs in single words or sentence production after sham tDCS, and no improvement of noun production after anodal tDCS and speech-language treatment, production of verbs in sentences improved after a 10-session treatment block of anodal tDCS and behavioral therapy. Conclusion Administering a behavioral treatment that is impairment-based as well as functionally-based in conjunction with tDCS is both feasible and promising. Anodal tDCS in conjunction with behavioral intervention is a treatment approach that warrants continued investigation. The results will be discussed in relation to the tDCS and aphasia literature

Translational treatment of aphasia combining neuromodulation and behavioral intervention for lexical retrieval: implications from a single case study

Background: Transcranial direct current stimulation (tDCS), a non-invasive method of brain stimulation, is an adjunctive research-therapy for aphasia. The concept supporting translational application of tDCS is that brain plasticity, facilitated by language intervention, can be enhanced by non-invasive brain stimulation. This study combined tDCS with an ecologically focused behavioral approach that involved training nouns and verbs in sentences. Method: Participant: A 43-year-old, right-handed male with fluent-anomic aphasia who sustained a single-left-hemisphere-temporal-parietal stroke was recruited. Treatment: Instrumentation included the Soterix Medical 1 × 1 Device. Anodal tDCS was applied over Broca’s area. Behavioral materials included: sentence production, naming in the sentence context, and implementation of a social-conversational-discourse treatment. Design and Procedures: The independent variable of this crossover case-study was tDCS, and the dependent variables were language and quality-of-life measures. In each session the subject received language treatment with the first 20 minutes additionally including tDCS. Results: Performance in naming nouns and verbs in single words and sentences were obtained. Verb production in the sentence context increased after active anodal tDCS and speech-language treatment. Conclusion: Aphasia treatment that involves naming in the sentence context in conjunction with translational application of tDCS may be a promising approach for language-recovery post stroke

Consistency of Repeated Naming in Aphasia

Background People with mild aphasia and healthy elderly often exhibit similar impairments on language tests of word retrieval. However, variable practice effects in object naming by three individuals with aphasia compared to young and elderly adults have been reported (Wingfield et al. 2006). Wingfield et al. (2006) found that naming of the same pictures of objects over five trials demonstrated decreasing response latencies over repeated trials for both older and younger adults, but not for individuals with aphasia. In fact, among their three participants with aphasia, response latencies in the consecutive trials differed considerably. The authors suggested that different underlying processes may be involved in word retrieval for people with aphasia compared to adults without brain injuries. In our study we aimed to further consider the effect of practice on both object and action naming in individuals with mild aphasia. Method One woman with anomic aphasia (age 38 years; WAB Aphasia Quotient = 88) and one healthy woman (age 25 years) participated. Both were native English speakers and reported 18 years of formal education. Participants were tested individually, with a set of 27 object pictures and a set of 27 action pictures presented one at a time on a computer screen. The participants were instructed to name each picture as quickly as possible as soon as each picture appeared on the screen. There were 10 trials of each set of pictures, with different random orders for each trial. The order of presentation of the object and action picture sets alternated across participants. Naming responses were recorded to computer sound files for later measurements of response latencies. A brief tone was presented simultaneous with the picture onset, allowing later measurement of response latencies from the onset of picture presentation to the onset of the participant’s correct response. Results Our findings resembled those reported in Wingfield et al. (2006) in that the healthy participant demonstrated reduced latencies after the initial trial followed by a plateau, whereas the participant with aphasia had variable latencies across trials. Both participants had longer latencies for action naming than for object naming (mean .61 and .97 seconds for objects and 1.35 and 2.09 for actions for the healthy person and the participant with aphasia, respectively). The healthy participant demonstrated a pattern in which after the initial trial, response latencies decreased in both object and action naming; the person with aphasia demonstrated an initial decrease in the action naming only (see Figure). ANOVAs confirmed a main effect of Trial for the healthy participant for both object and action naming and for the action only for the person with aphasia. Conclusion Our data support that different underlying processes may be involved in word retrieval for people with aphasia compared to adults without brain injuries, even when additional trials are examined. The effect of repetition on verbs and nouns may differ. Data collection and analysis from additional participants is in progress

Use of Computational Modeling to Inform tDCS Electrode Montages for the Promotion of Language Recovery in Post-stroke Aphasia

Background: Although pilot trials of transcranial direct current stimulation (tDCS) in aphasia are encouraging, protocol optimization is needed. Notably, it has not yet been clarified which of the varied electrode montages investigated is the most effective in enhancing language recovery. Objective: To consider and contrast the predicted brain current flow patterns (electric field distribution) produced by varied 11 tDCS (1 anode, 1 cathode, 5 7 cm pad electrodes) montages used in aphasia clinical trials. Methods: A finite element model of the head of a single left frontal stroke patient was developed in order to study the pattern of the cortical EF magnitude and inward/outward radial EF under five different electrode montages: Anodal-tDCS (A-tDCS) over the left Wernicke’s area (Montage A) and over the left Broca’s area (Montage B); Cathodal tDCS (C-tDCS) over the right homologue of Wernicke’s area (Montage C), and of Broca’s area (Montage D), where for all montages A-D the “return” electrode was placed over the supraorbital contralateral forehead; bilateral stimulation with A-tDCS over the left Broca’s and CtDCS over the right Broca’s homologue (Montage E). Results: In all cases, the “return” electrode over the contralesional supraorbital forehead was not inert and influenced the current path through the entire brain. Montage B, although similar to montage D in focusing the current in the perilesional area, exerted the greatest effect over the left perilesional cortex, which was even stronger in montage E. Conclusions: The position and influence of both electrodes must be considered in the design and inter- pretation of tDCS clinical trials for aphasia