Heidi Roth - Academia.edu (original) (raw)

Papers by Heidi Roth

Sleep

Introduction: Sleep disturbances in TBI population can have negative consequences on physical, ps... more Introduction: Sleep disturbances in TBI population can have negative consequences on physical, psychological and cognitive recovery. While polysomnography (PSG) is the gold standard for evaluating sleep disorders, actigraphy has been widely used to screen for sleep-wake disorders, especially ones that change longitudinally. In a small sample of TBI patients (n=50, single center sample of convenience) during inpatient rehabilitation, we have previously found two models (Philips Actiwatch2/Actiwatch Spectrum) to be feasible and valid for collecting sleep data. Herein, we extend this validation to a prospective study of more than 200 TBI patients and include both the Actigraph Core wGT3X-BT (ACT-Core) and Philips Actiwatch Spectrum Plus (PASP). Methods: This is a secondary analysis from a six-center, prospective, observational cohort study from the TBI Model System Lifetimes Study where overnight, fully attended polysomnography with concomitant actigraphy were conducted on moderate to severe TBI subjects during acute inpatient rehabilitation as part of an ongoing PCORI-funded clinical trial. Actigraphy variables of total sleep time (TST), sleep efficiency (SE), sleep latency (SL), wake after sleep onset (WASO) were compared between actigraphy devices and with Level 1, fully attended PSG (Phillips Sleepware-G3) to evaluate their concordance (Pearson). PASP-derived sleep was determined with Actiware (sensitivity=Automatic), while ACT-Core-derived sleep was determined with ActiLife (Cole-Kripke algorithm). Results: Simultaneous collection of PSG and PASP (n=230) and ACT-Core (n=179) were examined. Correlations (p>.01) with PSG were found for both PASP and ACT-Core for TST (r=.70, .69), SE (r=.33, .31), and WASO (r=-.19,-.24) respectively. Comparison of actigraphy devices to one another revealed correlations (p>.01) for TST (r=.80), SE (r=.58), WASO (r=.68), and SL (r=.23). Conclusion: This larger, prospective study across six-centers supports the use of actigraphy as a proxy measure of sleep quantity (TST, SE) in acute neurorehabilitation admissions with moderate to severe TBI. No relationship was found for SL with mixed findings for WASO. Sensitivity analyses with subsets of TBI survivors with comorbidities (sleep apnea, spasticity, muscle strength) may affect agreement and warrant further study.

Children

Patients with Down syndrome (DS) are at risk for both obstructive sleep apnea (OSA) and central s... more Patients with Down syndrome (DS) are at risk for both obstructive sleep apnea (OSA) and central sleep apnea (CSA); however, it is unclear how these components evolve as patients age and whether patients are also at risk for hypoventilation. A retrospective review of 144 diagnostic polysomnograms (PSG) in a tertiary care facility over 10 years was conducted. Descriptive data and exploratory correlation analyses were performed. Sleep disordered breathing was common (seen in 78% of patients) with an average apnea-hypopnea index (AHI) = 10. The relative amount of obstructive apnea was positively correlated with age and body mass index (BMI). The relative amount of central sleep apnea was associated with younger age in the very youngest group (0-3 years). Hypoventilation was common occurring in more than 22% of patients and there was a positive correlation between the maximum CO 2 and BMI. Sleep disordered breathing, including hypoventilation, was common in patients with DS. The obstructive component increased significantly with age and BMI, while the central component occurred most in the very young age group. Due to the high risk of hypoventilation, which has not been previously highlighted, it may be helpful to consider therapies to target both apnea and hypoventilation in this population.

Neurology, Apr 8, 2014

OBJECTIVE: To determine whether obstructive sleep apnea (OSA) affects consolidation of perceptual... more OBJECTIVE: To determine whether obstructive sleep apnea (OSA) affects consolidation of perceptual skill learning, and whether this is restored with positive airway pressure (PAP) therapy. BACKGROUND: Large population studies of middle aged and elderly adults have found only inconsistent effects of OSA on memory. One explanation is that these studies used memory tests that are insensitive to sleep.The visual discrimination task (VDT) is a perceptual learning task that is enhanced by sleep intervals, and especially depends on REM sleep. DESIGN/METHODS: Overnight gains in VDT performance were compared in patients treated and not treated with PAP therapy. In Exp. 1, 18 subjects undergoing clinical polysomnograms were given the VDT before and after sleep. In Exp. 2, 14 subjects with known OSA underwent 3 nights of testing, including adjustment, treatment, and non-treatment nights. The VDT was given on counterbalanced treatment and non-treatment nights. RESULTS: In Exp. 1, patients given PAP therapy had better overnight perceptual skill learning compared to all patients without PAP therapy (t (16)=-2.60, p =.019), and compared to those patients with untreated apnea (t(11)=2.21, p= .049). In Exp. 2, a greater learning benefit occurred on therapy compared to off PAP therapy (t(13)=2.186, p=.048). The degree to which apnea was effectively treated in REM, but not NREM, correlated with benefit (r=.643, p=.013). Total sleep time and sleep efficiency were unchanged. CONCLUSIONS: These findings suggest that obstructive sleep apnea interferes with memory consolidation for perceptual skill learning, and that PAP therapy, including the degree to which PAP therapy treats apnea in REM, improves learning. Apnea in REM specifically has not previously been shown to have neurocognitive consequences, but these results suggest that residual disruption of REM by apnea interferes with memory consolidation. Disclosure: Dr. Roth has nothing to disclose. Dr. Hart has nothing to disclose. Dr. Sanders has nothing to disclose. Dr. Truong has nothing to disclose. Dr. Vaughn has received personal compensation in an editorial capacity for Medlink-Neurobase, Neurologic Clinics, and the American Board of Internal Medicine Sleep Examination Committee. Dr. Stickgold has nothing to disclose.

Journal of Traumatic Stress, 2014

Physiological hyperarousal is manifested acutely by increased heart rate, decreased respiratory s... more Physiological hyperarousal is manifested acutely by increased heart rate, decreased respiratory sinus arrhythmia, and increased skin conductance level and variability. Yet it is uncertain to what extent such activation occurs with the symptomatic hyperarousal of posttraumatic stress disorder (PTSD). We compared 56 male veterans with current PTSD to 54 males who never had PTSD. Subjects wore ambulatory devices that recorded electrocardiograms, finger skin conductance, and wrist movement while in their normal environments. Wrist movement was monitored to estimate sleep and waking periods. Heart rate, but not the other variables, was elevated in subjects with PTSD equally during waking and during actigraphic sleep (effect sizes, Cohen's d, ranged from 0.63 to 0.89). The length of the sleep periods and estimated sleep fragmentation did not differ between groups. Group heart rate differences could not be explained by differences in body activity, PTSD hyperarousal symptom scores, depression, physical fitness, or antidepressant use.

ChronoPhysiology and Therapy, 2014

Circadian rhythms and sleep influence a variety of physiological functions, including the digesti... more Circadian rhythms and sleep influence a variety of physiological functions, including the digestive system. The digestive system also has intrinsic rhythms that interact dynamically with circadian rhythms. New advances in understanding the interaction of these rhythms and sleep provide the prospect of evaluating their role in normal physiology and the link of their disruption to pathological conditions. Recent work has demonstrated that sleep and circadian factors influence appetite, nutrient absorption, and metabolism. Disruption of sleep and circadian rhythms may increase vulnerability to digestive disorders, including reflux, ulcers, inflammatory bowel issues, irritable bowel disease, and gastrointestinal cancer. As our knowledge of the link between circadian timing and gastrointestinal physiology grows, so do our opportunities to provide promising diagnostic and therapeutic approaches for gastrointestinal disorders.

Neurocase, 2006

This study examines a parallel distributed processing (PDP) model (partly based on the Wernicke-L... more This study examines a parallel distributed processing (PDP) model (partly based on the Wernicke-Lichtheim information processing model) that posits two routes for naming concepts, whole word and phonological. To test the two naming route hypothesis of this model, we performed confrontation naming tests that were either uncued, semantically cued, or phonologically cued in a patient with naming impairment due to Broca's aphasia. In spoken language and in uncued naming to confrontation, word retrieval was severely impaired and marked by semantic but no phonemic paraphasic errors. With semantic cues, naming behavior was unchanged; however, with phonological cues, naming success was enhanced but frequent phonemic paraphasias were produced. These results suggest that the patient spontaneously engaged the whole word naming route, but when given phonological cues, he engaged an alternative phonological naming route that incorporated phonological sequence knowledge.

Neurocase, 2014

In assessments of visuospatial function and memory, patients are often required to copy a figure ... more In assessments of visuospatial function and memory, patients are often required to copy a figure and later to reproduce that figure from memory. Whereas most people perform better on a copying task than when drawing from memory, in this study we describe an unusual pattern of performance in which patients are better at drawing from memory than copying. Consecutive patients in a neurocognitive disorders clinic were given a battery of clinical cognitive tests that included copying a figure of intersecting pentagons and then drawing the figure from memory. Patterns of drawing performance at the two time points were compared to the profile of other cognitive deficits. A subgroup of four patients with frontal dysfunction showed marked improvement in drawings at a delay compared to copying. Prior studies have indicated that most patients have declines in drawing performance at a delay. The unusual pattern of better performance at a delay compared to an initial copy occurred in patients with frontal dysfunction. These patients' visuoconstructive deficit and subsequent improvement could be related to either a failure to disengage when a model is present, to memory consolidation with increased reliance on top-down processing in the delay condition, or to relative preservation of global versus local aspects of a stimulus in memory. The addition of a task to assess drawing after a delay to a standard clinical screening battery such as the Mini-Mental Status Examination (MMSE) provides the opportunity to evaluate this phenomenon that may be indicative of frontal-executive dysfunction.

Journal of the International Neuropsychological Society, 1995

To assess if amnesics have intact remote memory for general semantic information, we examined mem... more To assess if amnesics have intact remote memory for general semantic information, we examined memory for vocabulary words with known dates of entry into the language between 1955 and 1989. Amnesics of mixed etiology with acute onset performed normally on both a recall and a recognition task. Korsakoff patients, in contrast, were impaired on both tasks and demonstrated a gradient such that their knowledge of words acquired during more recent time periods was worse than that of words acquired during more remote time periods. The improvement in performance associated with recognition testing was larger for Korsakoff patients than for control subjects and correlated significantly with a composite measure of frontal dysfunction. These findings suggest a deficit in the controlled search and retrieval of semantic information in Korsakoff patients. The implications of the differential performance of Korsakoff and mixed etiology amnesics for explanations of temporally graded retrograde amnes...

Journal of Speech, Language, and Hearing Research, 2012

Purpose We explored the reliability and validity of 2 quantitative approaches to document presenc... more Purpose We explored the reliability and validity of 2 quantitative approaches to document presence and severity of speech properties associated with apraxia of speech (AOS). Method A motor speech evaluation was administered to 39 individuals with aphasia. Audio-recordings of the evaluation were presented to 3 experienced clinicians to determine AOS diagnosis and to rate severity of 11 speech dimensions. Additionally, research assistants coded 11 operationalized metrics of articulation, fluency, and prosody in the same speech samples and in recordings from 20 neurologically healthy participants. Results Agreement among the 3 clinicians was limited for both AOS diagnosis and perceptual scaling, but inter-observer reliability for the operationalized metrics was strong. The relationships between most operationalized metrics and mean severity ratings for corresponding perceptual dimensions were moderately strong and statistically significant. Both perceptual scaling and operationalized q...

Journal of Neurolinguistics, 2010

JAMA: The Journal of the American Medical Association, 2004

Paul Matthews describes the center-stage role of the brain in famous scenes from Shakespeare'... more Paul Matthews describes the center-stage role of the brain in famous scenes from Shakespeare's plays with the use of colour brain scans. Interwoven with these are the interpretations of many of the most significant soliloquies in all of Shakespeare's plays.

Neurocase, 2006

A loss of speech can be related to disorders of the motor units (paresis), language deficits (aph... more A loss of speech can be related to disorders of the motor units (paresis), language deficits (aphasia), or speech programming deficits (apraxia of speech). Although apraxia of speech has been reported to be associated with degenerative diseases, we observed a patient with a unique constellation of signs that included apraxia of speech, oculo-orofacial apraxia and a supranuclear ophthalmoplegia in the absence of extrapyramidal (Parkinsonian) signs. Post-mortem examination revealed a loss of neurons in the frontal and temporal regions, but there was also a marked loss of neurons and astrogliosis in the caudate, claustrum, globus pallidus, substantia nigra, and loss of axons in the anterior cerebral peduncles. This patient's clinical presentation and the pathological correlates suggest that he might have suffered with a distinct disorder we call progressive oculo-orofacial-speech apraxia or POOSA.

Cognitive and Behavioral Neurology, 2010

Background/Objective: The fragile X-associated tremor/ataxia syndrome is characterized by intenti... more Background/Objective: The fragile X-associated tremor/ataxia syndrome is characterized by intention tremor and ataxia in people who are premutation carriers of the Fragile X gene. Patients with this disorder might also demonstrate signs of dementia with parkinsonian features. We report a patient with dementia and parkinsonian signs who did not demonstrate an intention tremor or gait ataxia. Methods: A 58-year-old woman who had 2 sons with fragile X retardation syndrome and was a carrier, developed progressive dementia, including impaired memory, executive dysfunction, nonfluent speech, and parkinsonian signs, but had no actionintention tremor and no gait ataxia. Magnetic resonance imaging revealed extensive abnormalities of the white matter. Results: On post-mortem examination, 7 years after this evaluation, she demonstrated extensive subcortical white matter pallor (spongiosis) and widespread ubiquitin-positive intranuclear inclusions in both neurons and in protoplasmic astrocytes characteristic of fragile X-associated tremor/ataxia syndrome, but no spongiosis in the cerebellar peduncles a defining feature of this tremor/ataxia syndrome. Conclusions: Patients who present with dementia and signs of Parkinson syndrome, even in the absence of ataxia or intention tremor should be evaluated for this fragile X dementia parkinsonism syndrome.

Neurocase, 2006

This study examines a parallel distributed processing (PDP) model (partly based on the Wernicke-L... more This study examines a parallel distributed processing (PDP) model (partly based on the Wernicke-Lichtheim information processing model) that posits two routes for naming concepts, whole word and phonological. To test the two naming route hypothesis of this ...

Brain, 2002

Observations in primates and patients with unilateral spatial neglect have suggested that patchin... more Observations in primates and patients with unilateral spatial neglect have suggested that patching of the eye ipsilateral to the injury and contralateral to the neglected space can sometimes improve attention to the neglected space. Investigators have generally attributed the effects of monocular eye patching to activation of subcortical centers that interact with cortical attentional systems. Eye patching is thought to produce preferential activation of attentional systems contralateral to the viewing eye. In this study we examined the effect of monocular eye patching on attentional biases in normal subjects. When normal subjects bisect vertical (radial) lines using both eyes, they demonstrate a far attentional bias, misbisecting lines away from their body. In a monocular viewing experiment, we found that the majority of subjects, who were right eye dominant, had relatively nearer bisections and a diminished far bias when they used their right eye (left eye covered) compared with when they used their left eye (right eye covered). The smaller group of subjects who were left eye dominant had relatively nearer bisections and a diminished far bias when they used their left eye compared with when they used their right eye. In the hemispatial placement experiment, we directly manipulated hemispheric engagement by having subjects perform the same task in right and left hemispace. We found that right eye dominant subjects had a diminished far bias in right hemispace relative to left hemispace. Left eye dominant subjects showed the opposite pattern and had a diminished far bias in left hemispace. For both groups, spatial presentation affected performance more for the non-dominant eye. The results suggest that monocular viewing is associated with preferential activation of attentional systems in the contralateral hemisphere, and that the right hemisphere (at least in right eye dominant subjects) is biased towards far space. Finally, the results suggest that the poorly understood phenomenon of eye dominance may be related to hemispheric specialization for visual attention.

Brain and Cognition, 2005

The background page on which a stimulus is presented can influence the allocation of attention to... more The background page on which a stimulus is presented can influence the allocation of attention to that stimulus. The purpose of this study was to learn if there are hemispheric asymmetries in how background distraction affects attentional processing. Asymmetries were investigated by having right eye dominant subjects perform line bisections and manipulating the side of background distraction (right versus left), the eye of regard (right versus left), and the type of attention allocated (focal versus global). Overall subjects bisected lines to the left of center (pseudoneglect) and when viewing with the right eye (versus left) deviated more to the left. Subjects had more background distraction when viewing symbol than solid lines. Although overall, bias did not differ with the side of background distraction or the line being on one side or the other, when subjects viewed symbol, but not solid lines, this leftward bias was increased when the line was displaced to the right, thereby increasing the size of the left sided background. These findings suggest that when engaging the left hemisphere by using focused attention and placing the line on the right side, there is more distraction than when the right hemisphere is engaged.

Sleep

Introduction: Sleep disturbances in TBI population can have negative consequences on physical, ps... more Introduction: Sleep disturbances in TBI population can have negative consequences on physical, psychological and cognitive recovery. While polysomnography (PSG) is the gold standard for evaluating sleep disorders, actigraphy has been widely used to screen for sleep-wake disorders, especially ones that change longitudinally. In a small sample of TBI patients (n=50, single center sample of convenience) during inpatient rehabilitation, we have previously found two models (Philips Actiwatch2/Actiwatch Spectrum) to be feasible and valid for collecting sleep data. Herein, we extend this validation to a prospective study of more than 200 TBI patients and include both the Actigraph Core wGT3X-BT (ACT-Core) and Philips Actiwatch Spectrum Plus (PASP). Methods: This is a secondary analysis from a six-center, prospective, observational cohort study from the TBI Model System Lifetimes Study where overnight, fully attended polysomnography with concomitant actigraphy were conducted on moderate to severe TBI subjects during acute inpatient rehabilitation as part of an ongoing PCORI-funded clinical trial. Actigraphy variables of total sleep time (TST), sleep efficiency (SE), sleep latency (SL), wake after sleep onset (WASO) were compared between actigraphy devices and with Level 1, fully attended PSG (Phillips Sleepware-G3) to evaluate their concordance (Pearson). PASP-derived sleep was determined with Actiware (sensitivity=Automatic), while ACT-Core-derived sleep was determined with ActiLife (Cole-Kripke algorithm). Results: Simultaneous collection of PSG and PASP (n=230) and ACT-Core (n=179) were examined. Correlations (p>.01) with PSG were found for both PASP and ACT-Core for TST (r=.70, .69), SE (r=.33, .31), and WASO (r=-.19,-.24) respectively. Comparison of actigraphy devices to one another revealed correlations (p>.01) for TST (r=.80), SE (r=.58), WASO (r=.68), and SL (r=.23). Conclusion: This larger, prospective study across six-centers supports the use of actigraphy as a proxy measure of sleep quantity (TST, SE) in acute neurorehabilitation admissions with moderate to severe TBI. No relationship was found for SL with mixed findings for WASO. Sensitivity analyses with subsets of TBI survivors with comorbidities (sleep apnea, spasticity, muscle strength) may affect agreement and warrant further study.

Children

Patients with Down syndrome (DS) are at risk for both obstructive sleep apnea (OSA) and central s... more Patients with Down syndrome (DS) are at risk for both obstructive sleep apnea (OSA) and central sleep apnea (CSA); however, it is unclear how these components evolve as patients age and whether patients are also at risk for hypoventilation. A retrospective review of 144 diagnostic polysomnograms (PSG) in a tertiary care facility over 10 years was conducted. Descriptive data and exploratory correlation analyses were performed. Sleep disordered breathing was common (seen in 78% of patients) with an average apnea-hypopnea index (AHI) = 10. The relative amount of obstructive apnea was positively correlated with age and body mass index (BMI). The relative amount of central sleep apnea was associated with younger age in the very youngest group (0-3 years). Hypoventilation was common occurring in more than 22% of patients and there was a positive correlation between the maximum CO 2 and BMI. Sleep disordered breathing, including hypoventilation, was common in patients with DS. The obstructive component increased significantly with age and BMI, while the central component occurred most in the very young age group. Due to the high risk of hypoventilation, which has not been previously highlighted, it may be helpful to consider therapies to target both apnea and hypoventilation in this population.

Neurology, Apr 8, 2014

OBJECTIVE: To determine whether obstructive sleep apnea (OSA) affects consolidation of perceptual... more OBJECTIVE: To determine whether obstructive sleep apnea (OSA) affects consolidation of perceptual skill learning, and whether this is restored with positive airway pressure (PAP) therapy. BACKGROUND: Large population studies of middle aged and elderly adults have found only inconsistent effects of OSA on memory. One explanation is that these studies used memory tests that are insensitive to sleep.The visual discrimination task (VDT) is a perceptual learning task that is enhanced by sleep intervals, and especially depends on REM sleep. DESIGN/METHODS: Overnight gains in VDT performance were compared in patients treated and not treated with PAP therapy. In Exp. 1, 18 subjects undergoing clinical polysomnograms were given the VDT before and after sleep. In Exp. 2, 14 subjects with known OSA underwent 3 nights of testing, including adjustment, treatment, and non-treatment nights. The VDT was given on counterbalanced treatment and non-treatment nights. RESULTS: In Exp. 1, patients given PAP therapy had better overnight perceptual skill learning compared to all patients without PAP therapy (t (16)=-2.60, p =.019), and compared to those patients with untreated apnea (t(11)=2.21, p= .049). In Exp. 2, a greater learning benefit occurred on therapy compared to off PAP therapy (t(13)=2.186, p=.048). The degree to which apnea was effectively treated in REM, but not NREM, correlated with benefit (r=.643, p=.013). Total sleep time and sleep efficiency were unchanged. CONCLUSIONS: These findings suggest that obstructive sleep apnea interferes with memory consolidation for perceptual skill learning, and that PAP therapy, including the degree to which PAP therapy treats apnea in REM, improves learning. Apnea in REM specifically has not previously been shown to have neurocognitive consequences, but these results suggest that residual disruption of REM by apnea interferes with memory consolidation. Disclosure: Dr. Roth has nothing to disclose. Dr. Hart has nothing to disclose. Dr. Sanders has nothing to disclose. Dr. Truong has nothing to disclose. Dr. Vaughn has received personal compensation in an editorial capacity for Medlink-Neurobase, Neurologic Clinics, and the American Board of Internal Medicine Sleep Examination Committee. Dr. Stickgold has nothing to disclose.

Journal of Traumatic Stress, 2014

Physiological hyperarousal is manifested acutely by increased heart rate, decreased respiratory s... more Physiological hyperarousal is manifested acutely by increased heart rate, decreased respiratory sinus arrhythmia, and increased skin conductance level and variability. Yet it is uncertain to what extent such activation occurs with the symptomatic hyperarousal of posttraumatic stress disorder (PTSD). We compared 56 male veterans with current PTSD to 54 males who never had PTSD. Subjects wore ambulatory devices that recorded electrocardiograms, finger skin conductance, and wrist movement while in their normal environments. Wrist movement was monitored to estimate sleep and waking periods. Heart rate, but not the other variables, was elevated in subjects with PTSD equally during waking and during actigraphic sleep (effect sizes, Cohen's d, ranged from 0.63 to 0.89). The length of the sleep periods and estimated sleep fragmentation did not differ between groups. Group heart rate differences could not be explained by differences in body activity, PTSD hyperarousal symptom scores, depression, physical fitness, or antidepressant use.

ChronoPhysiology and Therapy, 2014

Circadian rhythms and sleep influence a variety of physiological functions, including the digesti... more Circadian rhythms and sleep influence a variety of physiological functions, including the digestive system. The digestive system also has intrinsic rhythms that interact dynamically with circadian rhythms. New advances in understanding the interaction of these rhythms and sleep provide the prospect of evaluating their role in normal physiology and the link of their disruption to pathological conditions. Recent work has demonstrated that sleep and circadian factors influence appetite, nutrient absorption, and metabolism. Disruption of sleep and circadian rhythms may increase vulnerability to digestive disorders, including reflux, ulcers, inflammatory bowel issues, irritable bowel disease, and gastrointestinal cancer. As our knowledge of the link between circadian timing and gastrointestinal physiology grows, so do our opportunities to provide promising diagnostic and therapeutic approaches for gastrointestinal disorders.

Neurocase, 2006

This study examines a parallel distributed processing (PDP) model (partly based on the Wernicke-L... more This study examines a parallel distributed processing (PDP) model (partly based on the Wernicke-Lichtheim information processing model) that posits two routes for naming concepts, whole word and phonological. To test the two naming route hypothesis of this model, we performed confrontation naming tests that were either uncued, semantically cued, or phonologically cued in a patient with naming impairment due to Broca's aphasia. In spoken language and in uncued naming to confrontation, word retrieval was severely impaired and marked by semantic but no phonemic paraphasic errors. With semantic cues, naming behavior was unchanged; however, with phonological cues, naming success was enhanced but frequent phonemic paraphasias were produced. These results suggest that the patient spontaneously engaged the whole word naming route, but when given phonological cues, he engaged an alternative phonological naming route that incorporated phonological sequence knowledge.

Neurocase, 2014

In assessments of visuospatial function and memory, patients are often required to copy a figure ... more In assessments of visuospatial function and memory, patients are often required to copy a figure and later to reproduce that figure from memory. Whereas most people perform better on a copying task than when drawing from memory, in this study we describe an unusual pattern of performance in which patients are better at drawing from memory than copying. Consecutive patients in a neurocognitive disorders clinic were given a battery of clinical cognitive tests that included copying a figure of intersecting pentagons and then drawing the figure from memory. Patterns of drawing performance at the two time points were compared to the profile of other cognitive deficits. A subgroup of four patients with frontal dysfunction showed marked improvement in drawings at a delay compared to copying. Prior studies have indicated that most patients have declines in drawing performance at a delay. The unusual pattern of better performance at a delay compared to an initial copy occurred in patients with frontal dysfunction. These patients' visuoconstructive deficit and subsequent improvement could be related to either a failure to disengage when a model is present, to memory consolidation with increased reliance on top-down processing in the delay condition, or to relative preservation of global versus local aspects of a stimulus in memory. The addition of a task to assess drawing after a delay to a standard clinical screening battery such as the Mini-Mental Status Examination (MMSE) provides the opportunity to evaluate this phenomenon that may be indicative of frontal-executive dysfunction.

Journal of the International Neuropsychological Society, 1995

To assess if amnesics have intact remote memory for general semantic information, we examined mem... more To assess if amnesics have intact remote memory for general semantic information, we examined memory for vocabulary words with known dates of entry into the language between 1955 and 1989. Amnesics of mixed etiology with acute onset performed normally on both a recall and a recognition task. Korsakoff patients, in contrast, were impaired on both tasks and demonstrated a gradient such that their knowledge of words acquired during more recent time periods was worse than that of words acquired during more remote time periods. The improvement in performance associated with recognition testing was larger for Korsakoff patients than for control subjects and correlated significantly with a composite measure of frontal dysfunction. These findings suggest a deficit in the controlled search and retrieval of semantic information in Korsakoff patients. The implications of the differential performance of Korsakoff and mixed etiology amnesics for explanations of temporally graded retrograde amnes...

Journal of Speech, Language, and Hearing Research, 2012

Purpose We explored the reliability and validity of 2 quantitative approaches to document presenc... more Purpose We explored the reliability and validity of 2 quantitative approaches to document presence and severity of speech properties associated with apraxia of speech (AOS). Method A motor speech evaluation was administered to 39 individuals with aphasia. Audio-recordings of the evaluation were presented to 3 experienced clinicians to determine AOS diagnosis and to rate severity of 11 speech dimensions. Additionally, research assistants coded 11 operationalized metrics of articulation, fluency, and prosody in the same speech samples and in recordings from 20 neurologically healthy participants. Results Agreement among the 3 clinicians was limited for both AOS diagnosis and perceptual scaling, but inter-observer reliability for the operationalized metrics was strong. The relationships between most operationalized metrics and mean severity ratings for corresponding perceptual dimensions were moderately strong and statistically significant. Both perceptual scaling and operationalized q...

Journal of Neurolinguistics, 2010

JAMA: The Journal of the American Medical Association, 2004

Paul Matthews describes the center-stage role of the brain in famous scenes from Shakespeare'... more Paul Matthews describes the center-stage role of the brain in famous scenes from Shakespeare's plays with the use of colour brain scans. Interwoven with these are the interpretations of many of the most significant soliloquies in all of Shakespeare's plays.

Neurocase, 2006

A loss of speech can be related to disorders of the motor units (paresis), language deficits (aph... more A loss of speech can be related to disorders of the motor units (paresis), language deficits (aphasia), or speech programming deficits (apraxia of speech). Although apraxia of speech has been reported to be associated with degenerative diseases, we observed a patient with a unique constellation of signs that included apraxia of speech, oculo-orofacial apraxia and a supranuclear ophthalmoplegia in the absence of extrapyramidal (Parkinsonian) signs. Post-mortem examination revealed a loss of neurons in the frontal and temporal regions, but there was also a marked loss of neurons and astrogliosis in the caudate, claustrum, globus pallidus, substantia nigra, and loss of axons in the anterior cerebral peduncles. This patient's clinical presentation and the pathological correlates suggest that he might have suffered with a distinct disorder we call progressive oculo-orofacial-speech apraxia or POOSA.

Cognitive and Behavioral Neurology, 2010

Background/Objective: The fragile X-associated tremor/ataxia syndrome is characterized by intenti... more Background/Objective: The fragile X-associated tremor/ataxia syndrome is characterized by intention tremor and ataxia in people who are premutation carriers of the Fragile X gene. Patients with this disorder might also demonstrate signs of dementia with parkinsonian features. We report a patient with dementia and parkinsonian signs who did not demonstrate an intention tremor or gait ataxia. Methods: A 58-year-old woman who had 2 sons with fragile X retardation syndrome and was a carrier, developed progressive dementia, including impaired memory, executive dysfunction, nonfluent speech, and parkinsonian signs, but had no actionintention tremor and no gait ataxia. Magnetic resonance imaging revealed extensive abnormalities of the white matter. Results: On post-mortem examination, 7 years after this evaluation, she demonstrated extensive subcortical white matter pallor (spongiosis) and widespread ubiquitin-positive intranuclear inclusions in both neurons and in protoplasmic astrocytes characteristic of fragile X-associated tremor/ataxia syndrome, but no spongiosis in the cerebellar peduncles a defining feature of this tremor/ataxia syndrome. Conclusions: Patients who present with dementia and signs of Parkinson syndrome, even in the absence of ataxia or intention tremor should be evaluated for this fragile X dementia parkinsonism syndrome.

Neurocase, 2006

This study examines a parallel distributed processing (PDP) model (partly based on the Wernicke-L... more This study examines a parallel distributed processing (PDP) model (partly based on the Wernicke-Lichtheim information processing model) that posits two routes for naming concepts, whole word and phonological. To test the two naming route hypothesis of this ...

Brain, 2002

Observations in primates and patients with unilateral spatial neglect have suggested that patchin... more Observations in primates and patients with unilateral spatial neglect have suggested that patching of the eye ipsilateral to the injury and contralateral to the neglected space can sometimes improve attention to the neglected space. Investigators have generally attributed the effects of monocular eye patching to activation of subcortical centers that interact with cortical attentional systems. Eye patching is thought to produce preferential activation of attentional systems contralateral to the viewing eye. In this study we examined the effect of monocular eye patching on attentional biases in normal subjects. When normal subjects bisect vertical (radial) lines using both eyes, they demonstrate a far attentional bias, misbisecting lines away from their body. In a monocular viewing experiment, we found that the majority of subjects, who were right eye dominant, had relatively nearer bisections and a diminished far bias when they used their right eye (left eye covered) compared with when they used their left eye (right eye covered). The smaller group of subjects who were left eye dominant had relatively nearer bisections and a diminished far bias when they used their left eye compared with when they used their right eye. In the hemispatial placement experiment, we directly manipulated hemispheric engagement by having subjects perform the same task in right and left hemispace. We found that right eye dominant subjects had a diminished far bias in right hemispace relative to left hemispace. Left eye dominant subjects showed the opposite pattern and had a diminished far bias in left hemispace. For both groups, spatial presentation affected performance more for the non-dominant eye. The results suggest that monocular viewing is associated with preferential activation of attentional systems in the contralateral hemisphere, and that the right hemisphere (at least in right eye dominant subjects) is biased towards far space. Finally, the results suggest that the poorly understood phenomenon of eye dominance may be related to hemispheric specialization for visual attention.

Brain and Cognition, 2005

The background page on which a stimulus is presented can influence the allocation of attention to... more The background page on which a stimulus is presented can influence the allocation of attention to that stimulus. The purpose of this study was to learn if there are hemispheric asymmetries in how background distraction affects attentional processing. Asymmetries were investigated by having right eye dominant subjects perform line bisections and manipulating the side of background distraction (right versus left), the eye of regard (right versus left), and the type of attention allocated (focal versus global). Overall subjects bisected lines to the left of center (pseudoneglect) and when viewing with the right eye (versus left) deviated more to the left. Subjects had more background distraction when viewing symbol than solid lines. Although overall, bias did not differ with the side of background distraction or the line being on one side or the other, when subjects viewed symbol, but not solid lines, this leftward bias was increased when the line was displaced to the right, thereby increasing the size of the left sided background. These findings suggest that when engaging the left hemisphere by using focused attention and placing the line on the right side, there is more distraction than when the right hemisphere is engaged.