Christine H. Davis

Comparison of the neural basis for imagined writing and drawing

Drawing and writing are complex processes that require the synchronization of cognition, language, and perceptual‐motor skills. Drawing and writing have both been utilized in the treatment of aphasia to improve communication. Recent research suggests that the act of drawing an object facilitated naming, whereas writing the word diminished accurate naming in individuals with aphasia. However, the relationship between object drawing and subsequent phonological output is unclear. Although the right hemisphere is characteristically mute, there is evidence from split‐brain research that the right hemisphere can integrate pictures and words, likely via a semantic network. We hypothesized that drawing activates right hemispheric and left perilesional regions that are spared in aphasic individuals and may contribute to semantic activation that supports naming. Eleven right‐handed subjects participated in a functional MRI (fMRI) experiment involving imagined drawing and writing and 6 of the 11 subjects participated in a second fMRI experiment involving actual writing and drawing. Drawing and writing produced very similar group activation maps including activation bilaterally in the premotor, inferior frontal, posterior inferior temporal, and parietal areas. The comparison of drawing vs. writing revealed significant differences between the conditions in areas of the brain known for language processing. The direct comparison between drawing and writing revealed greater right hemisphere activation for drawing in language areas such as Brodmann area (BA) 46 and BA 37. Hum. Brain Mapp, 2007.

Self-perception in mild traumatic brain injury.

Davis CH: Self-perception in mild traumatic brain injury. Am J Phys Med Rehabil 2002;81:609–618. Objective The objectives of this study were (1) to describe a procedure for measuring preinjury and postinjury symptoms, (2) to compare these symptoms with normal controls and individuals with non–head related traumas, (3) to describe patterns in persistent symptomatology after mild traumatic brain injury, and (4) to document trends in self-perception as measured by retrospective ratings of symptoms after trauma. Design A total of 102 individuals with mild traumatic brain injury and 69 individuals with non-head-related traumas completed preinjury and postinjury symptom questionnaires 1 wk after trauma. Symptoms were compared with 115 normal controls. Three months after injury, a subgroup of the mild traumatic brain injury group completed symptom questionnaires again. A factor analysis and subsequent discriminant function analysis of the symptoms differentiated the groups. Results Retrospective ratings of preinjury symptoms by the two trauma groups were significantly less than the normal controls, implying misattribution. Most symptoms were somatic at 1 wk postinjury in both trauma groups. At 3 mo, the mild traumatic brain injury group endorsed more recall symptoms. Conclusions The procedure was useful in differentiating groups by symptom patterns and increasing our knowledge of persistent symptomatology after mild traumatic brain injury. Misattribution, the unrealistic self-perception of symptoms after the event of a trauma, was detected in both the head and non-head trauma groups.

Intensive semantic intervention in fluent aphasia: A pilot study with fMRI

Background : This pilot study presents a method of rehabilitation based on the assumption that there is a widely distributed neural network that supports semantic processing and that can be used to improve word retrieval without explicit naming. It employs functional imaging to help understand the neural basis of response to treatment. Aims : There are both behavioural and neural questions. First, this study investigates whether intensive therapy designed to reduce production errors by eliminating oral responses can yield improved naming of trained items. Second, it investigates whether changes in naming will be associated with changes in fMRI activation and whether the changes in activation pattern associated with recovery are primarily in the right hemisphere lpar;RH) or in perilesional tissue. Methods & Procedures : Four weeks of intensive semantic therapy designed to activate the semantic network and minimise errors was administered to AT, an individual with Wernickes aphasia. Pre- and post-therapy behavioural testing included standard tests of aphasia, naming of pictures from training sets, and a narrative speech sample. Functional imaging of experimental and control tasks was completed pre- and post-therapy. Outcomes & Results : After 4 weeks of training, AT demonstrated improved naming and showed increased use of nouns in narrative speech. FMRI demonstrated increased activation of the left inferior frontal cortex during verb generation as well as increased inferior posterior temporal RH activation. Conclusions : These results support the effectiveness of intensive intervention methods that require semantic judgements rather than naming and the use of fMRI to understand the neural basis of the response.

Drawing: Its Contribution to Naming in Aphasia.

Drawing in aphasia therapy has been used predominately as a substitution for speech or to augment communication when other modalities are non-functional. The value of drawing as a route for facilitating verbal expression has not been a focus of prior research. We compared the usefulness of drawing and writing as compensatory strategies for improving naming in individuals with aphasia. Activation patterns of writing and drawing in healthy adults were examined using fMRI. Clinical results suggest that drawing facilitated naming whereas writing diminished accurate naming responses, and that drawing quality is not relevant to this facilitatory effect. Functional MRI findings revealed strong bi-hemispheric activation of semantic and phonological networks while drawing that may support our clinical findings.

The neural basis for simulated drawing and the semantic implications

This functional magnetic resonance imaging (fMRI) study of the mental simulation of drawing (1) investigated the neural substrates of drawing and (2) delineated the semantic aspects of drawing. The goal was to advance our understanding of how drawing a familiar object is linked to lexical semantics and therefore a viable method to use to rehabilitate aphasia. We hypothesized that the semantic aspects of drawing familiar objects compared to drawing non-objects would yield greater activation in the inferior temporal cortex and the inferior frontal cortex of the left hemisphere. To test this hypothesis, eight right-handed subjects performed an fMRI experiment that directly contrasted drawing familiar objects to non-objects using mental imagery. Simulated drawing recruited a large, distributed network of frontal, parietal, and temporal structures. In the contrast comparing drawing familiar objects to non-objects there was stronger activation in the left hemisphere within the inferior temporal, anterior inferior frontal, inferior parietal and superior frontal cortices. The activation within the inferior temporal cortex was associated with visual semantic processing and semantic mediated naming. We suggest that the anterior inferior frontal activation is linked to the inferior temporal cortex and is involved in the selection of specific semantic features of the object as well as retrieval of information regarding the perceptual aspects of the object.

Profiles of functional recovery in fifty traumatically brain-injured patients after acute rehabilitation

Research to demonstrate the efficacy of head injury rehabilitation is important at a time when cost-containment efforts are intensifying. A useful tool that would predict the functional improvement during hospitalization and length of stay (LOS) of persons with traumatic brain injury would be of benefit to patients and their families, insurance carriers, and rehabilitation specialists. This study examines functional improvements made by 50 traumatic brain-injured patients admitted to the rehabilitation unit at the University of California, Davis, Medical Center (UCDMC) as measured by the UCDMC Davis Functional Status Measure (DFSM), which was adapted from the Functional Independence Measure (FIM). The DFSM incorporates additional items to provide a more thorough measure of skills to be rehabilitated. The purpose of this study was to compare scores and profiles on the DFSM items obtained by patients with LOS greater than and less than and equal to the median rehabilitation LOS (23 days). Relationships were explored among admission DFSM scores, LOS for rehabilitation, discharge destination, and functional outcome. Results indicate that patients admitted to the rehabilitation unit attained a similar profile or level of function by discharge, regardless of admission Glasgow Coma Scale scores or admission DFSM scores. There were no significant differences in admission Glasgow Coma Scale score, age, acute LOS, or discharge disposition between the LOS groups. There was a significant difference in median admission DFSM score in 26 of 31 categories between the LOS groups. There was a significant difference in median DFSM change (admission to discharge) in 24 of 31 categories between the LOS groups. The admission DFSM total score was inversely proportional to the length of stay, with a correlation coefficient of 0.78. DFSM change and admission to discharge was linearly correlated with LOS (R = 0.66). The DFSM documents functional outcome and measures gains during inpatient rehabilitation. The DFSM profile is helpful in predicting the LOS needed to achieve those gains.

Understanding the effects of cuing strategies through error analysis

The aim of this study was to understand the effectiveness of two self-cuing strategies for naming in individuals with aphasia through the analysis of error types. In previous work, Farias, Davis, Lundstrom, and Osecheck (2002) found that after failed naming attempts, drawing facilitated access to the object name more than attempts to access the name through orthographic self-cuing. Drawing, which is free of linguistic symbols inherent in traditional modes of therapy (Lyon, 1995), may provide an alternate route to the object name. Drawing may facilitate a deeper level of semantic processing through increased attention to the structural and perceptual aspects of the object. In the process of drawing the individual accesses and attends to the details of the object. This systematic focus of attention may help to either inhibit the competitors of the target or increase activation of appropriate features of the desired target. We hypothesize that individuals with left brain damage, who fail to name an object, may access the semantic knowledge of that object by drawing it and thereby improve access to the name or produce error types that are closer to the target. Here, we compare the distribution of naming errors in eight individuals with left brain damage while using the self-cuing strategies of drawing and writing. Writing provided a good control condition because it is a common strategy used in aphasia therapy for facilitating naming and like drawing it requires a graphic output. Additionally, writing is known to activate primarily left hemisphere regions, whereas drawing may activate semantic networks that are represented bilaterally (Makuuchi, Kaminaga, & Sugishita, 2003), and remain intact in the undamaged right hemisphere.

Treating apraxia of speech with an implicit protocol that activates speech motor areas via inner speech

Background: Treatments of apraxia of speech (AOS) have traditionally relied on overt practice. One alternative to this method is implicit phoneme manipulation which was derived from early models on inner speech. Implicit phoneme manipulation requires the participant to covertly move and combine phonemes to form a new word. This process engages a system of self-monitoring which is referred to as fully conscious inner speech. Aims: The present study aims to advance the understanding and validity of a new treatment for AOS, implicit phoneme manipulation. Tasks were designed to answer the following questions. (1) Would the practice of implicit phoneme manipulation improve the overt production of complex consonant blends in words? (2) Would this improvement generalise to untrained complex and simpler consonant blends in words? (3) Would these treatment tasks activate regions known to support motor planning and programming as verified by functional magnetic resonance imaging (fMRI)? Method & Procedures: The participant was asked to covertly manipulate phonemes to create a new word and to associate this newly formed word to a target picture among four phonologically related choices. To avoid overt practice, probes were collected only after each block of training was completed. Probe sessions assessed the effects of implicit practice on the overt production of simple and complex consonant blends in words. An imaging protocol compared semantic baseline tasks to treatment tasks to verify that implicit phoneme manipulation activated brain regions of interest. Outcomes & Results: Behavioural: Response to implicit training of complex consonant blends resulted in improvements which were maintained 6 weeks after treatment. Further, this treatment generalised to simpler consonant blends in words. Imaging: Functional imaging during implicit phoneme manipulation showed significant activation in brain regions responsible for phonological processing when compared to the baseline semantic task. Conclusions: Implicit phoneme manipulation offers an alternative to traditional methods that require overt production for treatment of AOS. Additionally, this implicit treatment method was shown to activate neural areas known to be involved in phonological processing, motor planning, and programming.