Lesion site patterns in severe, nonverbal aphasia to predict outcome with a computer-assisted treatment program.

OBJECTIVE: To test whether lesion site patterns in patients with chronic, severe aphasia who have no meaningful spontaneous speech are predictive of outcome following treatment with a nonverbal, icon-based computer-assisted visual communication (C-ViC) program. DESIGN: Retrospective study in which computed tomographic scans performed 3 months after onset of stroke and aphasia test scores obtained before C-ViC therapy were reviewed for patients after receiving C-ViC treatment. SETTING: A neurology department and speech pathology service of a Department of Veterans Affairs medical center and a university aphasia research center. PATIENTS: Seventeen patients with stroke and severe aphasia who began treatment with C-ViC from 3 months to 10 years after onset of stroke. MAIN OUTCOME MEASURE: Level of ability to use C-ViC on a personal computer to communicate. RESULTS: All patients with bilateral lesions failed to learn C-ViC. For patients with unilateral left hemisphere lesion sites, statistical analyses accurately discriminated between those who could initiate communication with C-ViC from those who were only able to answer directed questions. The critical lesion areas involved temporal lobe structures (Wernicke cortical area and the subcortical temporal isthmus), supraventricular frontal lobe structures (supplementary motor area or cingulate gyrus 24), and the subcortical medial subcallosal fasciculus, deep to the Broca area. Specific lesion sites were also identified for appropriate candidacy for C-ViC. CONCLUSIONS: Lesion site patterns on computed tomographic scans are helpful to define candidacy for C-ViC training, and to predict outcome level. A practical method is presented for clinical application of these lesion site results in combination with aphasia test scores.

Visible changes in lesion borders on CT scan after five years poststroke, and long-term recovery in aphasia.

This study examined 12 aphasia patients at approximately 1 year poststroke (Time 1) and again at 5-12 years poststroke (Time 2) with language testing and CT scan. Significant increases in naming scores, and phrase length in nonfluent speech were observed after 5 years poststroke. Significant expansion in visible lesion borders (lesion size) was observed after 5 years poststroke; an increase in lesion size of > 1% was present in 9/12 cases (75%). Not one case had a second stroke. Thus, it appears that even though lesion expansion may occur after 5 years poststroke, as long as this expansion is unilateral and gradual, it has no adverse effect on language, and in fact, continued recovery in naming and nonfluent speech may also occur. Long-term recovery patterns in aphasia which may be associated with brain reorganization deserve further study, especially with functional brain imaging techniques.

The use of high-efficiency particulate air-filter respirators to protect hospital workers from tuberculosis. A cost-effectiveness analysis.

BACKGROUND: After outbreaks of multidrug-resistant tuberculosis, the Centers for Disease Control and Prevention proposed the use of respirators with high-efficiency particulate air filters (HEPA respirators) as part of isolation precautions against tuberculosis, along with a respiratory-protection program for health care workers that includes medical evaluation, training, and tests of the fit of the respirators. Each HEPA respirator costs between $7.51 and $9.08, about 10 times the cost of respirators currently used. METHODS: We conducted a cost-effectiveness analysis using data from the University of Virginia Hospital on exposure to patients with tuberculosis and rates at which the purified-protein-derivative (PPD) skin test became positive in hospital workers. The costs of a respiratory-protection program were based on those of an existing program for workers dealing with hazardous substances. RESULTS: During 1992, 11 patients with documented tuberculosis were admitted to our hospital. Eight of 3852 workers (0.2 percent) had PPD tests that became positive. Five of these conversions were believed to be due to the booster phenomenon; one followed unprotected exposure to a patient not yet in isolation; the other two occurred in workers who had never entered a tuberculosis isolation room. These data suggest that it will take more than one year for the use of HEPA respirators to prevent a single conversion of the PPD test. Assuming that one conversion is prevented per year, however, it would take 41 years at out hospital to prevent one case of occupationally acquired tuberculosis, at a cost of $1.3 million to $18.5 million. CONCLUSIONS: Given the effectiveness of currently recommended measures to prevent nosocomial transmission of tuberculosis, the addition of HEPA respirators would offer negligible protective efficacy at great cost.

Neuroimaging and language recovery in stroke.

This article reviews the use of a chronic computed tomography (CT) scan (performed after 2 or 3 months following stroke onset) in assessing a patient's potential for recovery of speech and comprehension in the long term (after 6-12 months following stroke onset). Not all aphasia patients recover the ability to produce meaningful speech after a stroke. This article discusses the neuroanatomical areas to be examined on CT scan, in order to predict which stroke patients are not likely to recover meaningful speech, even for as long as 10 years following stroke onset. These neuroanatomical areas are located in deep, subcortical white matter areas; they are not in the cortex. It is important to have information regarding potential for long-term recovery of speech, so that appropriate non-verbal treatment programs can be initiated. A non-verbal computer-assisted treatment program is presented, in which severely affected patients are taught to communicate using pictures and icons on a computer screen.

Temporal dimensions of consonant and vowel production: an acoustic and CT scan analysis of aphasic speech.

This study explored a number of temporal (durational) parameters of consonant and vowel production in order to determine whether the speech production impairments of aphasics are the result of the same or different underlying mechanisms and in particular whether they implicate deficits that are primarily phonetic or phonological in nature. Detailed analyses of CT scan lesion data were also conducted to explore whether more specific neuroanatomical correlations could be made with speech production deficits. A series of acoustic analyses were conducted including voice-onset time, intrinsic and contrastive fricative duration, and intrinsic and contrastive vowel duration as produced by Broca's aphasics with anterior lesions (A patients), nonfluent aphasics with anterior and posterior lesions (AP patients), and fluent aphasics with posterior lesions (P patients). The constellation of impairments for the anterior aphasics including both the A and AP patients suggests that their disorder primarily reflects an inability to implement particular types of articulatory gestures or articulatory parameters rather than an inability to implement particular phonetic features. They display impairments in the implementation of laryngeal gestures for both consonant and vowel production. These patterns seem to relate to particular anatomical sites involving Broca's area, the anterior limb of the internal capsule, and the lowest motor cortex areas for larynx and tongue. The posterior patients also show evidence of subtle phonetic impairments suggesting that the neural instantiation of speech may require more extensive involvement, including the perisylvian area, than previously suggested.

Late recovery of auditory comprehension in global aphasia. Improved recovery observed with subcortical temporal isthmus lesion vs Wernicke's cortical area lesion.

This study examined the relationship between recovery of auditory comprehension in global aphasia patients after 1 year post onset, and temporal lobe lesion in Wernicke's cortical area vs temporal lobe lesion in the subcortical temporal isthmus area. Computed tomographic scans and language behavior were examined in 14 right-handed globally aphasic stroke patients with lesion in the left hemisphere. Nine patients had large cortical/subcortical frontal, parietal, and temporal lobe lesion that included more than half of Wernicke's cortical area (FPT cases). Five patients had large cortical/subcortical frontal and parietal lobe lesion, but only subcortical temporal lobe lesion, including the temporal isthmus (FPTi cases). All patients were tested acutely at 1 to 4 months post onset and again at 1 to 2 years post onset. There was a significantly greater increase in the amount of recovery that had taken place after 1 to 2 years post onset for the FPTi group vs the FPT group in the overall Boston Diagnostic Aphasia Examination (BDAE) Auditory Comprehension Z score. In four of the five FPTi cases, the late BDAE Auditory Comprehension Z scores were above -0.5 (mild-to-moderate comprehension deficits). Most recovery was in single-word comprehension. In eight of the nine FPT cases, the late BDAE Auditory Comprehension Z-scores were below -0.5 (moderate-to-severe comprehension deficits). There was no significant difference between the two groups in recovery of spontaneous speech, repetition, or naming, where severe deficits remained in most cases.(ABSTRACT TRUNCATED AT 250 WORDS)

Severe nonfluency in aphasia. Role of the medial subcallosal fasciculus and other white matter pathways in recovery of spontaneous speech.

The relationship between location and extent of lesion on CT scan and limitation in spontaneous speech was examined. The severity of spontaneous speech ranged from cases with no speech or only verbal stereotypies (first major group) to those with reduced, hesitant, poorly articulated, agrammatic speech (nonfluent Broca's aphasia, second major group). CT scan analysis revealed no single neuroanatomical area that contained an extensive lesion which could be used to discriminate the most severe cases from the least severe. The two groups were separable, however, on the basis of the CT scan when the extent of the lesion in two subcortical white matter areas were combined: (1) the most medial and rostral portion of the subcallosal fasciculus plus (2) the periventricular white matter near the body of the lateral ventricle, deep to the lower motor/sensory cortex area for the mouth. The most rostral portion of the medial subcallosal fasciculus, located in the lateral angle of the frontal horn (extremely deep to Broca's area), contains projections from the cingulate gyrus (area 24) and the supplementary motor area, to the caudate nucleus. We suggest that one explanation for the more severe limitation in spontaneous speech in the first group is the extensive white matter lesion in these two subcortical pathways had interrupted a large number of connections for (1) initiation and preparation of speech movements, and limbic aspects of speech (lesions in the medial subcallosal fasciculus), and (2) motor execution and sensory feedback for spontaneous speech (lesions in periventricular white matter deep to the motor/sensory cortex area for the mouth). Extensive lesion in only one of these two white matter pathway areas, alone was not sufficient to produce long-lasting severe limitation in spontaneous speech and could not be used to discriminate the two groups on the basis of the CT scans. The patients with less severe limitation in spontaneous speech (nonfluent Broca's aphasia) had less extensive lesion within these two white matter areas combined, and had interrupted a smaller number of these subcortical connections. The sites of the lesions in subcortical white matter in CT scans in Broca's original case who could only produce a verbal stereotypy are similar to those in our first group with the most severe limitation in spontaneous speech. The presence or absence of hemiplegia was not related to severity or recovery of spontaneous speech. Careful examination of lesion extent in these two areas of subcortical white matter on CT scanning appears to be relevant in predicting potential for recovery of spontaneous speech in some stroke patients.

Correlations of subcortical CT lesion sites and aphasia profiles.

We have analysed the aphasia profiles of 19 cases with subcortical infarction or haemorrhage. Several components of the aphasic syndromes, especially sentence length and grammatical form (together compromising fluency), ease of speech initiation, articulation, voice volume, and auditory comprehension, were individually isolated for correlation with CT lesion site. Each component had a specific lesion site correlation, and lesions in various deep periventricular white matter regions were the critical ones for all components of aphasia. Simple tabulation of lesions as cortical or subcortical, and restricting analysis to lesions of basal ganglia would both have proved inadequate to account for clinical findings. A review of 61 subcortical cases in the neurological literature for which CT and aphasia data were available supports these conclusions.