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M D Devous

Publications and source records attributed to M D Devous.

At least 37 records · Page 2Linked to original sources
PubMed1994

Linguistic performance and regional cerebral blood flow in persons who stutter.

In a series of studies regarding CNS dysfunction in stuttering, we have examined linguistic and motoric performance in the context of measures of brain function. Previous studies of adults with developmental stuttering identified alterations in brain function (metabolic and electrophysiologic) in cortical regions implicated in models of speech motor control and language processing. We also identified a sub-group of these subjects who exhibited linguistic performance deficits related to speech performance deficits. The present study examined the hypothesis that adults who stutter and who show linguistic performance deficits will also show metabolic alterations in cortical regions classically related to language processing, whereas adults who stutter but who do not show linguistic performance deficits will not show these cortical metabolic alterations. Significant relative blood flow asymmetry (left < right) was observed in middle temporal and inferior frontal cortical regions only for adults who both stuttered and showed linguistic performance deficits. Results support models that explicitly recognize that efficient integration of linguistic, motoric, and cognitive processes is critical to the production of oral/verbal fluency and to understanding sources of fluency failure.

Adult↗
PubMed1993

Regional cerebral blood flow alterations in unipolar depression.

Forty-seven symptomatic inpatients and outpatients with major depression (13 nonendogenous, 23 endogenous, and 11 psychotic by Research Diagnostic Criteria) were compared with 138 normal control subjects. Absolute regional cerebral blood flow (rCBF, ml/minute/100 g) was measured with 133Xe single photon emission computed tomography. Flow ratios (region of interest/global flow) and residual scores (the difference between patient flow ratios and expected normal flow ratios, as derived from the control population) were also computed. Results revealed significant age x region x depression subtype interactions for absolute, ratio, and residual flow data. Consequently, a test of group means (or analysis of covariance) could not be used to examine between-group differences. Multiple regression analyses were employed to study the effects of age on rCBF. This analysis revealed that different, though sometimes overlapping, regions exhibited different age effects on rCBF in different depressive subtypes. Thus, diagnostic-subtype-dependent age effects on rCBF precluded comparisons of mean values within or across regions for subject groups, but distinguished between symptomatic depressed patients and control subjects and among patient groups. Possible causes of such effects include variations in duration of illness or medication history or sensitization phenomena.

Adolescent↗
PubMed1993

Brain blood flow SPECT in temporary balloon occlusion of carotid and intracerebral arteries.

It is important to determine preoperatively which patients can tolerate permanent occlusion of a cervical internal carotid or cerebral artery when such a procedure may be necessary to treat cerebrovascular or neoplastic lesions. Here we report our experience in combining temporary intra-arterial balloon occlusion with concomitant cerebral blood flow imaging in preoperative evaluation of such patients. Forty-two patients with a variety of cerebrovascular and neoplastic lesions underwent trial balloon occlusion of an internal carotid or intracerebral artery. Eight patients developed both neurologic symptoms as well as brain perfusion defects during trial occlusion. Nine others developed only perfusion defects. The remainder were asymptomatic and had negative scans. Brain blood flow imaging during intra-arterial balloon occlusion identified 17 patients potentially at risk for developing postsurgical ischemic deficits. Treatment alternatives to acute arterial sacrifice were developed for these patients.

Adolescent↗
PubMed1993

Comparison of technetium-99m-ECD to Xenon-133 SPECT in normal controls and in patients with mild to moderate regional cerebral blood flow abnormalities.

Technetium-99m-1,1-ethyl cysteinate dimer (ECD) has been proposed as a "chemical microsphere" for SPECT measurement of regional cerebral blood flow (rCBF). However, its distribution has not yet been compared in humans to an established rCBF measure. Therefore, we compared the uptake and distribution of ECD with rCBF measured by 133Xe SPECT in subjects with mild to moderate flow abnormalities and in normal volunteers. Blood and urine chemistries and vital signs were unchanged from pre-ECD values up to seven days postinjection. Profile plots demonstrated pattern agreement between rCBF ratios (133Xe) and ECD count density ratios. A significant correlation of rCBF ratios to ECD count density ratios was observed (r = 0.77), with a slope of 0.64 and intercept of 0.36. To explore whether or not the relationship between rCBF and ECD was dependent on absolute flow, ECD region of interest data were expressed in units of ml/min/100 g by equating global CBF (133Xe) and ECD global count density. A closer correlation (r = 0.88) was found for these data than for the count ratio data. The slope was closer to one (m = 0.83) and the intercept was closer to zero (b = 8.2). Also, a significant correlation was observed between ECD-derived rCBF and 133Xe rCBF in the lesion area (r = 0.92) for patients with well-demarcated rCBF lesions. The slope (0.80) suggested a slight underestimation of lesion flow by ECD. Finally, ECD clearance from cortical gray matter ROIs derived from high-resolution scans from 1 to 4 hr postinjection was slow (2.4%/hr). In summary, ECD is a safe and effective marker of regional cerebral perfusion. The distribution of ECD is linearly related to rCBF measured by 133Xe SPECT, although our data suggest a mild underestimation of flow at the high end of the normal range.

Adult↗
PubMed1992

Brain blood flow related to acoustic laryngeal reaction time in adult developmental stutterers.

The 1980s witnessed renewed interest in the relation between developmental stuttering and central nervous system (CNS) abnormalities. We have reported differences between nonstutterers and developmental stutterers on electrophysiologic (QTE) and metabolic (rCBF) measures of brain function. A critical step in the interpretation of results of functional brain imaging studies is to determine the relation, if any, of identified CNS abnormalities to speech motor control in persons who stutter. In this study we addressed the interpretation of rCBF findings by asking whether we could identify patterns of impaired acoustic laryngeal reaction time (LRT) as a function of response complexity parallel to rCBF findings. Stutterer subgroups determined by clinical severity ratings were not differentiated by LRT values as a function of response complexity. Stutterers with relative blood flow asymmetry below the normal median value involving both left superior and middle temporal regions of interest (ROIs) showed significantly longer LRT for the complex response than did normal speakers and stutterers with above-normal median relative flow values to at least one of these temporal ROIs. Stutterer subgroups based on reduced cingulate flow alone were not differentiated by LRT values. Findings are consistent with Goldberg's (1985) model of CNS premotor processing. Findings also suggest that stutterer subgroups might be distinguished by the presence, loci, and relative magnitude of cortical and/or subcortical rCBF abnormality in regions that subserve a fluency-generating system.

Adult↗
PubMed1992

The use of acetazolamide-enhanced regional cerebral blood flow measurement to predict risk to arteriovenous malformation patients.

Regional hemodynamic disturbances may complicate the treatment of certain cerebral arteriovenous malformations (AVM) and occasionally produce life-threatening situations. Acetazolamide-enhanced quantitative regional cerebral blood flow studies were performed preoperatively in 35 patients to determine if patterns of vasoreactivity could be identified that might be markers for postoperative morbidity. Ipsilateral and contralateral regions of hypoperfusion were identified on resting studies, and a steal index was calculated by dividing the regional cerebral blood flow in the steal region by the flow in a normal cerebellar region. Flow in these regions of interest was again quantitated after the administration of acetazolamide, a known cerebral vasodilator. A delta value was calculated by subtracting the resting index values from the acetazolamide indices. Abnormally enhanced vasoreactivity (vasodilation) to acetazolamide stimulation was noted in these threatened territories in AVM that had perforating vessel feeding and angiographic steal phenomena, that developed hyperemic disturbances, and that resulted in poor outcomes. These findings call into question traditional theories of AVM-related hemodynamic decompensation and suggest unique smooth muscle derangements in cerebral vasculature in some AVM patients.

Acetazolamide↗
PubMed1992

Dual-isotope brain SPECT imaging with technetium-99m and iodine-123: clinical validation using xenon-133 SPECT.

Our phantom studies indicate that the energy resolution (9.7% FWHM) of a new three-headed single-photon tomograph (PRISM-3000) separates the distribution of 99mTc from 123I for 10% asymmetric or 15% or 10% centered 99mTc windows when combined with a 10% asymmetric 123I window. This technique is now applied to the simultaneous measurement of resting rCBF and changes induced by vasodilation (1 g acetazolamide) in 10 subjects with cerebrovascular disease. Resting and vasodilated 133Xe SPECT images were obtained first. Within 48 hr, 99mTc HMPAO was given at rest, acetazolamide injected, and after 20 min either [123I] IMP or [123I] HIPDM was administered. Subjects were scanned for 99mTc and 123I simultaneously using 10% asymmetric windows. Regression analyses demonstrated a linear relationship between 133Xe SPECT and dual-isotope SPECT measurements of lesion-to-cerebellum ratios in baseline (r = 0.92), vasodilated (r = 0.86) and rest-minus-vasodilated data (r = 0.85). Technetium-99m and 123I images obtained through dual-isotope imaging are by definition in perfect anatomic registration.

Acetazolamide↗
PubMed1992

Dual-isotope brain SPECT imaging with technetium-99m and iodine-123: validation by phantom studies.

Phantom studies were employed to determine whether the enhanced energy resolution (9.7% FWHM) of a new high-resolution, three-headed single-photon emission computed tomograph might permit the simultaneous acquisition of 99mTc and (123)I. Various window widths (15% and 10%) and positions (centered and asymmetric to the photopeak) were used to examine cross-contamination between these two isotopes. Brain phantom experiments using a 15% centered 99mTc window in conjunction with a 10% asymmetric (123)I window (upper half of the (123)I photopeak) demonstrated that approximately 95% of observed counts were derived from the isotope of interest. Shifting the (123)I window from asymmetric to centered resulted in a significant increase in contamination of the (123)I window. Shifting the 99mTc window from centered to asymmetric did not significantly alter image quality for 99mTc. Separate experiments employing vials with varying isotope concentrations demonstrated that quantitative recovery from mixed 99mTc and (123)I sources was equivalent to that from matched single-isotope sources (r2 > or = to 0.90).

Brain↗
PubMed1992

Comparison of SPECT applications in neurology and psychiatry.

The following presentation provides an overview of SPECT brain imaging applications in both neurologic and psychiatric disorders. Specific findings in cerebrovascular disease, dementia, and epilepsy are described in order to highlight the role SPECT plays in distinguishing primary organic disease from primary psychopathology. Through case examples, new applications of three-dimensional SPECT rCBF imaging that could play a major role in defining CNS network abnormalities in major depressive disorder and obsessive compulsive disorder are elucidated. The role of network imaging analysis across groups in psychiatric subjects is contrasted to its roles in neurologic disorders. The degree to which both neurologic and psychiatric pathology seen on SPECT exceeds that observed through structural modalities is defined.

Brain↗
PubMed1991

Heterogeneity in spasmodic dysphonia. Neurologic and voice findings.

Spasmodic dysphonia is a disturbance of phonation with laryngeal spasms. We report voice and neurologic examination findings in 45 subjects. Neurologic abnormalities were found in 32 subjects (71.1%). Rapid alternating movement abnormalities, weakness, and tremor were common. Incoordination and spasticity were rare. Lower extremity findings were frequent. Abnormalities were bilateral. Spasmodic dysphonia severity was related to age. Type, severity, and duration of vocal symptoms were not different for subjects with or without neurologic abnormalities. Vocal tremor was more frequent in neurologically abnormal subjects. Involvement of a pallidothalamic-supplementary motor area system could account for neurologic findings, brain imaging findings, and clinical heterogeneity. The view emerging is that spasmodic dysphonia is a manifestation of disordered motor control involving systems of neurons rather than single anatomical sites.

Adult↗
PubMed1991

Regional cerebral blood flow in developmental stutterers.

Stuttering is a poorly understood communication disorder with a 1% global prevalence. Recently, there has been a resurgence of interest in a neurogenic origin for the disorder, although no research has established clear neurological differences between "developmental" (stuttering onset in childhood) stutterers and nonstutterers. We have used xenon 133 single-photon emission computed tomography to study regional cerebral blood flow (rCBF) in 20 stutterers. Analysis revealed global, absolute flow reductions. Relative flow asymmetries (left less than right) were identified in three hemispheric regions: anterior cingulate and superior and middle temporal gyri. Milder changes were found in the left inferior frontal gyrus. Stutterers had rCBF values below median for either anterior cingulate or middle temporal gyri. With one exception, severe stutterers had rCBF values below median for the anterior cingulate gyrus. All stutterers with rCBF values above median in the cingulate gyrus had rCBF values below median in the middle temporal gyrus, and severity of their disorder was either mild or moderate. Our findings suggest that stuttering is a neurogenic disorder involving recognized cortical regions of speech-motor control.

Adult↗
PubMed1991

Laryngeal reaction time profiles in spasmodic dysphonia: relationship to cortical electrophysiologic abnormality.

This study combines measures of linguistic and vocal performance and long-latency auditory electrophysiology to investigate task-dependent variability in spasmodic dysphonia (SD). Linguistic performance was evaluated using several measures of relatively complex linguistic ability (i.e., discourse analysis). Vocal performance was evaluated by measuring acoustic laryngeal reaction time (LRT) for tasks that differ in complexity. Normal structure of the cortex and subcortex was confirmed by magnetic resonance imaging. Cortical function was measured using multichannel quantitative auditory evoked potentials (AEPs). As a group, SD subjects who demonstrated subtle linguistic deficits also demonstrated prolonged LRT for the complex task and repeated and persistent auditory electrophysiologic abnormalities over the anterior quadrant of the left hemisphere. As a group, linguistically normal SD subjects demonstrated no significant increase in LRT for the complex task and no recurrent electrophysiologic abnormalities over the left anterior cortex relative to normal controls. Results support a neurogenic origin of SD and suggest that some aspects of inter- and intrasubject variability may be related to differences in loci and magnitude of cortical abnormalities.

Adult↗
PubMed1990

Hypofrontality and cognitive impairment in schizophrenia: dynamic single-photon tomography and neuropsychological assessment of schizophrenic brain function.

Regional cerebral blood flow (rCBF) was assessed in 40 chronic male schizophrenic patients (20 medicated, 20 unmedicated) and 31 matched normal controls with Dynamic Single-photon Emission Computed Tomography (D-SPECT). Blind analyses of normalized color-coded tomograms revealed significant bifrontal and bitemporal rCBF deficits in the patient group. Frontal flow deficits were most prominent in paranoid patients (n = 21) and right temporal deficits were most prominent in nonparanoid patients (n = 19). These relative regional declines were observed within the context of significantly elevated hemispheric blood flow in schizophrenics compared with controls. Reduced left frontal rCBF was associated with neuropsychological impairment on the Wisconsin Card Sorting Test and Luria-Nebraska Battery. Increased hemispheric CBF was correlated with the presence of positive schizophrenic symptoms. Medication status was unrelated to rCBF. These findings demonstrate that hypofrontality has important implications for cognitive function in some schizophrenic individuals.

Adult↗
PubMed1990

Evidence for cortical dysfunction in spasmodic dysphonia: regional cerebral blood flow and quantitative electrophysiology.

Cortical function was evaluated in 26 subjects with spasmodic dysphonia. Quantitative topographic electrophysiologic mapping (QTE) was employed to provide quantitative analyses of EEG spectra and auditory and visual long-latency evoked potentials. Single-photon emission computed tomography (SPECT) of the cerebral transit of Xenon-133 was used to evaluate regional cerebral blood flow. Left hemispheric abnormalities in cortical function were found by both techniques in 10 subjects and by at least one technique in 18 subjects. Right hemispheric abnormalities were observed by both techniques in 8 subjects and by at least one technique in 18 subjects. Most patients with cortical dysfunction in one hemisphere had cortical dysfunction in the other, while only 4 subjects had unilateral lesions as found by one of the two techniques. Eight subjects were normal by all measurements. Underlying structural abnormalities were detected by magnetic resonance imaging in 5/24 subjects. However, functional abnormalities (SPECT or QTE) were not observed at sites of structural abnormalities. SPECT and QTE were significantly related in identification of left hemispheric dysfunction (p = .037) with a trend in the right hemisphere (p = .070), and a significant congruence of SPECT and QTE findings occurred in the left anterior cortical quadrant (p = .011). These findings indicate that dysfunction of cortical perfusion and/or cortical electrophysiology is associated with spasmodic dysphonia in the majority of subjects studied.

Adult↗