Paving the way for speech: voice-training-induced plasticity in chronic aphasia and apraxia of speech--three single cases.

Difficulties with temporal coordination or sequencing of speech movements are frequently reported in aphasia patients with concomitant apraxia of speech (AOS). Our major objective was to investigate the effects of specific rhythmic-melodic voice training on brain activation of those patients. Three patients with severe chronic nonfluent aphasia and AOS were included in this study. Before and after therapy, patients underwent the same fMRI procedure as 30 healthy control subjects in our prestudy, which investigated the neural substrates of sung vowel changes in untrained rhythm sequences. A main finding was that post-minus pretreatment imaging data yielded significant perilesional activations in all patients for example, in the left superior temporal gyrus, whereas the reverse subtraction revealed either no significant activation or right hemisphere activation. Likewise, pre- and posttreatment assessments of patients' vocal rhythm production, language, and speech motor performance yielded significant improvements for all patients. Our results suggest that changes in brain activation due to the applied training might indicate specific processes of reorganization, for example, improved temporal sequencing of sublexical speech components. In this context, a training that focuses on rhythmic singing with differently demanding complexity levels as concerns motor and cognitive capabilities seems to support paving the way for speech.

Comparison of k-t SENSE/k-t BLAST with conventional SENSE applied to BOLD fMRI.

PURPOSE: To compare k-t BLAST (broad-use linear-acquisition speedup technique)/k-t SENSE (sensitivity encoding) with conventional SENSE applied to a simple fMRI paradigm. MATERIALS AND METHODS: Blood oxygen level-dependent (BOLD) functional magnetic resonance imaging (fMRI) was performed at 3 T using a displaced ultra-fast low-angle refocused echo (UFLARE) pulse sequence with a visual stimulus in a block paradigm. Conventional SENSE and k-t BLAST/k-t SENSE data were acquired. Also, k-t BLAST/k-t SENSE was simulated at different undersampling factors from fully sampled data after removal of lines of k-space data. Analysis was performed using SPM5. RESULTS: Sensitivity to the BOLD response in k-t BLAST/k-t SENSE was comparable with that of SENSE in images acquired at an undersampling factor of 2.3. Simulated k-t BLAST/k-t SENSE yielded reliable detection of activation-induced BOLD contrast at undersampling factors of 5 or less. Sensitivity increased significantly when training data were included in k-space before Fourier transformation (known as "plug-in"). CONCLUSION: k-t BLAST/k-t SENSE performs at least as well as conventional SENSE for BOLD fMRI at a modest undersampling factor. Results suggest that sufficient sensitivity to BOLD contrast may be achievable at higher undersampling factors with k-t BLAST/k-t SENSE than with conventional parallel imaging approaches, offering particular advantages at the highest magnetic field strengths.

Correlation of passivity symptoms and dysfunctional visuomotor action monitoring in psychosis.

Passivity experiences are hallmark symptoms of schizophrenia that can be characterized by the belief that one's thoughts or actions are controlled by an external agent. It has recently been suggested that these psychotic experiences result from defective monitoring of one's own actions, i.e. disturbed comparison of actions and perceived outcomes. In this study, we examined the function of the previously characterized action monitoring network of the inferior parietal lobule (IPL), medial (mPFC) and lateral prefrontal cortices in patients with different levels of passivity symptoms with an fMRI task. The visuomotor fMRI task demanded control of visually perceived object movements by alternating button presses with the left and the right index finger. In the monitoring condition of this task subjects stopped their actions whenever they detected visuomotor incongruence. fMRI and behavioural data from 15 patients were tested for correlation with passivity symptoms using standardized Scale for Assessment of Positive Symptoms (SAPS)- and AMDP- passivity symptom ratings. Both types of data were tested for differences between the patients group and 15 healthy controls. In the patient group we found the expected correlation of passivity symptoms and visuomotor monitoring performance. There was a significant positive correlation of passivity symptoms with increased latency of incongruence detection and a negative correlation of SAPS-passivity with the number of detected events. fMRI data revealed correlations of passivity symptoms with activation in bilateral IPL, primary motor and sensory cortices in the action monitoring condition. A correlation of passivity symptoms with the main experimental effect (actions with -- actions without monitoring) was found in the posterior cingulate cortex (PCC) and in the left IPL. No group differences or group by task interactions were found within the visuomotor-action-monitoring network. Our results demonstrate the association between passivity symptoms and the dysfunction of visuomotor action monitoring and support the idea that psychotic passivity experiences result from dysfunctions of central action monitoring mechanisms: According to pre-existing concepts of parietal cortex function, IPL-hyperactivation may represent an increase in false detections of visuomotor incongruence while the correlation between passivity and the differential effect of monitoring on PCC-activation assumedly represents greater self-monitoring effort in passivity experiences.

All for one but not one for all: how multiple number representations are recruited in one numerical task.

Number processing recruits a complex network of multiple numerical representations. Usually the components of this network are examined in a between-task approach with the disadvantage of relying upon different instructions, tasks, and inhomogeneous stimulus sets across different studies. A within-task approach may avoid these disadvantages and access involved numerical representations more specifically. In the present study we employed a within-task approach to investigate numerical representations activated in the number bisection task (NBT) using parametric rapid event-related fMRI. Participants were to judge whether the central number of a triplet was also its arithmetic mean (e.g. 23_26_29) or not (e.g. 23_25_29). Activation in the left inferior parietal cortex was associated with the deployment of arithmetic fact knowledge, while activation of the intraparietal cortex indicated more intense magnitude processing, instrumental aspects of calculation and integration of the base-10 structure of two-digit numbers. These results replicate evidence from the literature. Furthermore, activation in the dorsolateral and ventrolateral prefrontal cortex revealed mechanisms of feature monitoring and inhibition as well as allocation of cognitive resources recruited to solve a specific triplet. We conclude that the network of numerical representations should rather be studied in a within-task approach than in varying between-task approaches.

Long-term outcome of speech and language in children after corrective surgery for cyanotic or acyanotic cardiac defects in infancy.

The purpose of this prospective study was to assess whether outcome of speech and language in children 5-10 years after corrective surgery for tetralogy of Fallot (TOF) or ventricular septal defect (VSD) in infancy was influenced by the preoperative condition of hypoxemia or cardiac insufficiency and whether it was associated with perioperative risk factors and neurodevelopmental outcome. A total of 35 unselected children, 19 with TOF and hypoxemia and 16 with VSD and cardiac insufficiency, operated with combined deep hypothermic circulatory arrest and low-flow cardiopulmonary bypass at mean age 0.7+/-0.3 (mean+/-standard deviation) years, underwent, at mean age 7.4+/-1.6 years, standardized evaluation of speech and language functions. Results were compared between subgroups and related to perioperative factors, sociodemographic and neurodevelopmental status. Age at testing, socioeconomic status and history of speech and language development were not different between the subgroups. In contrast, total scores on oral and speech motor control functions (TFS) as well as on oral and speech apraxia (Mayo Test) were significantly reduced (p<0.02 to <0.05), and scores on anatomical oral structures tended to be lower (p<0.09) in the TOF group as compared to the VSD group. No differences were found for auditory word recognition and phonological awareness as assessed by the Auditory Closure subtest of the Illinois Test of Psycholinguistic Abilities and the test of auditory analysis skills, respectively. In all children, higher age at testing and better socioeconomic status were associated with better results in all domains of assessment (p<0.001 to <0.04). Consistent impairments of all oral and speech motor control functions (TFS and Mayo Test) were present in 29% of all children with a mean age of 6.5 years in contrast to 43% with normal performance and a mean age of 8.3 years. On the receptive speech tasks, only 6% scored below the normal range of their age group. TFS subscores were significantly correlated with age, bypass duration and motor function, but not correlated with socioeconomic status, duration of cardiac arrest, intelligence and academic achievement. Children with preoperative hypoxemia due to cyanotic cardiac defects in infancy are at higher risk for dysfunction in speech and language than those with cardiac insufficiency due to acyanotic heart defects. Age at testing, socioeconomic status, and duration of cardiopulmonary bypass influenced test results. Long-term outcome in speech and language functions can be considered as a sensitive indicator of overall child development after cardiac surgery.

The neurofunctional mechanisms of traumatic and non-traumatic memory in patients with acute PTSD following accident trauma.

Neurofunctional alterations in acute posttraumatic stress disorder (PTSD) and changes thereof during the course of the disease are not well investigated. We used functional magnetic resonance imaging to assess the functional neuroanatomy of emotional memory in surgical patients with acute PTSD. Traumatic (relative to non-traumatic) memories increased neural activity in the amygdala, hippocampus, lateral temporal, retrosplenial, and anterior cingulate cortices. These regions are all implicated in memory and emotion. A comparison of findings with data on chronic PTSD suggests that brain circuits affected by the acute disorder are extended and unstable while chronic disease is characterized by circumscribed and stable neurofunctional abnormalities.

Long-term neurodevelopmental outcomes in school-aged children after neonatal arterial switch operation.

OBJECTIVE: Neurodevelopmental status of children between 8 and 14 years of age after neonatal arterial switch operation for transposition of the great arteries has not previously been systematically evaluated. METHODS: Within a longitudinal study, 60 unselected children operated on as neonates with combined deep hypothermic circulatory arrest and low-flow cardiopulmonary bypass were reevaluated at the age of 7.9 to 14.3 years (mean +/- SD 10.5 +/- 1.6 years). Clinical neurologic status and standardized tests to assess gross motor function, intelligence, acquired abilities, language, and speech were carried out, and the results were related to preoperative, perioperative, and postoperative status, to management, and to neurodevelopmental status at a mean age of 5.4 years. RESULTS: Neurologic and speech impairments were evidently more frequent (27% and 40%, respectively) than in the general population. Intelligence and socioeconomic status were not different (P =.29 and P =.11), whereas motor function, acquired abilities, and language were reduced (P < or =.04 for each). Overall rate of developmental impairment in one or more domains was 55%, compared with 26% at age 5.4 years. Multivariable analysis showed that severe preoperative acidosis and hypoxia predicted reduced motor function (mean deficit 52.7 points, P <.001), whereas longer bypass duration predicted both neurologic (odds ratio per 10 minutes of bypass duration 1.8, P =.04) and speech (odds ratio per 10 minutes of bypass duration 1.9, P =.02) dysfunction, and perioperative and postoperative cardiocirculatory insufficiency predicted neurologic (odds ratio 6.5, P =.04) and motor (mean deficit 6.8 points, P =.03) dysfunction. CONCLUSIONS: The neonatal arterial switch operation with combined circulatory arrest and low-flow bypass is associated increasingly with age, with reduced neurodevelopmental outcome but not with cognitive dysfunction. In our experience, the risk of long-term neurodevelopmental impairment after neonatal corrective cardiac surgery is related to deleterious effects of the global perioperative management and to special adverse effects of prolonged bypass duration. Severe preoperative acidosis and hypoxia and postoperative hemodynamic instability must be considered as important additional risk factors.

Neural correlates of working memory in pure and polyvalent ecstasy (MDMA) users.

Poor cognitive performance in ecstasy (3,4-methylenedioxymethamphetamine; MDMA) users has been related to the well-recognized neurotoxic effects of the drug upon central serotonergic and possibly also dopaminergic systems. However, concomitant use of other drugs has been a critical confound in most investigations. In this study we used an n-back task and fMRI to investigate working memory performance and related cerebral activation in eight, currently abstinent pure MDMA users and two matched groups of polyvalent MDMA users and non-users. Pure MDMA users presented lower activations than controls and/or polyvalent users, most notably in inferior temporal regions, the angular gyrus and the striate cortex, whereas polyvalent users did not differ from controls. Our results suggest that altered brain activation patterns during cognitive processing in ecstasy users may be mainly associated with prior MDMA use. Concomitant use of other drugs may modify this effect.

Neurologic and psycho-intellectual outcome related to structural brain imaging in adolescents and young adults after neonatal arterial switch operation for transposition of the great arteries.

OBJECTIVE: We studied brain structure abnormalities in adolescents and young adults who had undergone the neonatal arterial switch operation for transposition of the great arteries and related them to the neurologic and psycho-intellectual outcomes. METHODS: In a prospective longitudinal study, 60 unselected adolescents and young adults who had undergone surgery with combined deep hypothermic circulatory arrest and low flow cardiopulmonary bypass were re-evaluated at a mean age of 16.9±1.7 years to determine their clinical neurologic status, intellectual development, and psychological condition. The results were related to population norms and anatomic structural abnormalities assessed by brain magnetic resonance imaging, with consideration of the risk factors in the preoperative and perioperative periods. RESULTS: Neurologic impairment was more frequent (10%) than in the normal population. Although the average full-scale, verbal, and performance intelligence quotients were not reduced, scores>2 standard deviations less than the expected mean were increased. Above average scores were found for analytical thinking, but the orthography testing results were reduced. The self-rated psychological condition was better than expected. Magnetic resonance imaging demonstrated moderate or severe structural brain abnormalities in 32% of the patients. Periventricular leukomalacia was detected in >50%; its severity correlated with the grade of neurologic impairment, which correlated significantly with reduced intelligence, analytical thinking, and orthography. Preoperative acidosis and hypoxia were the only independent patient-related risk factors for neurologic dysfunction, reduced intelligence, periventricular leukomalacia, and reduced brain volume. CONCLUSIONS: Despite encouraging overall neurodevelopmental outcomes, a significant minority had performances below the expected level, emphasizing the need for ongoing surveillance. Considering the high frequency of structural brain abnormalities, prospective long-term studies are needed to define their prognostic value with respect to the neuropsychological outcomes in childhood and adolescence.

The impact of rhythm complexity on brain activation during simple singing: an event-related fMRI study.

PURPOSE: Since rhythmical aspects of singing have been neglected up to now our objective was to investigate if it was possible to specify areas concerned with rhythm processing during simple singing. METHODS: In an event-related fMRI experiment we tested 30 healthy non-musicians with rhythm sequences, which had to be repeated as monotonously sung vowel changes with (1) regular groupings, (2) regular groupings and rests, and (3) irregular groupings. RESULTS: Common activations for all conditions were found in bilateral supplementary motor area, premotor cortex more distinct in the left hemisphere, left cingulate gyrus, and right basal ganglia. Only irregular groupings making the highest demands on attention, working memory, and sequencing capabilities resulted in additional activation of pars orbitalis and insula more distinct in the left hemisphere, as well as bilateral cingulate gyrus, and parietal lobes. Our analyses demonstrated that bilateral pars orbitalis (BA 47), insula, and left cingulate gyrus are core areas whose activity correlates with rhythm complexity. CONCLUSIONS: Rhythm structure is a decisive factor concerning lateralization as well as activation of specific areas during simple singing. This finding suggests a directed use of the singing voice e.g., in order to support language rehabilitation in patients.

Common networks for selective auditory attention for sounds and words? An fMRI study with implications for attention rehabilitation.

PURPOSE: In an fMRI study the functional networks involved in auditory selective attention for sounds and words were investigated. METHODS: 24 healthy volunteers (12 male, 12 female) had to respond to a category of targets (animal sounds vs. musical instruments, spoken names of instruments vs. animals; 6 targets, 12 nontargets) presented via headphones. RESULTS: Under both the sound and word condition besides left superior and middle temporal lobe activation there was bilateral activity in the superior frontal (including the anterior cingulate cortex ACC), middle and inferior frontal and inferior parietal lobes. Under both conditions we also found cerebellar activity. In general there was a high overlap of the related attention networks for both conditions. CONCLUSIONS: The activation patterns revealed a high overlap across stimulus conditions with only slight modulation caused by the quality of the auditory material. For rehabilitation of attention deficits after brain damage this implicates that a single training procedure might address a common network for selective attention deficits under different stimulus conditions.

Feasibility of k-t BLAST for BOLD fMRI with a spin-echo based acquisition at 3 T and 7 T.

OBJECTIVES: This study tested the feasibility of applying k-t BLAST to blood oxygen level dependent functional MRI of the brain at 3 Tesla (T) and at 7 T. Shorter echo train lengths, achieved through the application of k-t BLAST, are expected to counteract increased sensitivity to inhomogeneities in B0 at higher magnetic field strengths, especially in echo planar images, and reduce the relatively long acquisition times and high RF power deposition in spin-echo based methods. MATERIALS AND METHODS: k-t BLAST was combined with displaced UFLARE at 3 T and 7 T. Temporal and spatial fidelity of k-t BLAST were investigated using a test object, in which localized variations in signal intensity mimic activation-induced signal changes. fMRI was performed using typical box-car design finger tapping. In a separate analysis full k-space data were decimated to simulate k-t BLAST acquisitions and compare results with the fully sampled data, thereby avoiding physiological and noise differences between acquisitions. RESULTS: Activation can be detected at under-sampling factors as high as 16, whereas appropriately reconstructed data, under-sampled at factors below 8 entail insignificant loss of sensitivity and considerable reductions in acquisition times and RF power deposition. CONCLUSIONS: k-t BLAST is compatible with fMRI acquisitions and opens up possibilities including distortion-free T2*-weighted blood oxygen level dependent fMRI with displaced UFLARE at high magnetic field strengths.

Management of attentional resources in within-modal and cross-modal divided attention tasks: an fMRI study.

In the present study, we were interested in distinguishing the cortical representations of within-modal and cross-modal divided attention tasks by using functional magnetic resonance imaging. Sixteen healthy male subjects aged between 21 and 30 years underwent two within-modal (auditory/auditory, visual/visual) and one cross-modal (auditory/visual) divided attention task, as well as related selective attention control conditions. After subtraction of the corresponding control task the three divided attention tasks, irrespective of sensory modality, revealed significant activation in a predominantly right hemisphere network involving the prefrontal cortex, the inferior parietal cortex, and the claustrum. Under the cross-modal condition, however, the frontal and parietal activation was more extended and more bilateral and there also was stronger right hemisphere activation of the anterior cingulate cortex and the thalamus. In comparison to the within-modal conditions additional bilateral frontal and left inferior parietal activation was found for the cross-modal condition. The supplementary fronto-parietal, anterior cingulate cortex, and thalamus activation in the auditory/visual condition could be argued to reflect an additional demand for coordination of two ongoing cross-modal cognitive processes.

Acquired dyslexia after stroke in the prereading stage: a single case treatment study with f MRI.

The authors report a treatment study of a child (CK) who suffered a left-hemisphere stroke at age 6.3 years, a few months before beginning school. Despite complete recovery of spoken language abilities, CK failed to acquire written language abilities. Neurolinguistic assessment 2 years after the stroke revealed marked impairments in working memory, deficits in acquiring a sublexical reading strategy, and a very rudimentary orthographic network. Functional imaging demonstrated activation in posterior language areas during reading of familiar words while the attempt to read unfamiliar words activated peri- and contralesional structures of the anterior language areas. It was assumed that despite sufficient neural plasticity, the acquisition of a sublexical reading strategy was prevented by severe working memory deficits. Therefore, a specific treatment intervention was developed, choosing a compensatory strategy for reading remediation. Reading development was monitored over three months before and three months after an intensive training was conducted. Data showed significant gains in reading performance only after the specific intervention. These gains remained stable in a catamnesis 2 years later.

Neural processing of traumatic events in subjects suffering PTSD - a case study of two surgical patients with severe accident trauma.

Neuroimaging research on the neurobiology of chronic PTSD (posttraumatic stress disorder) has revealed structural and functional alterations primarily affecting areas of the medial temporal lobe (hippocampus, amygdala, and parahippocampal gyrus) and the frontal cortex known to be associated with the disorder. Using functional magnetic resonance imaging (fMRI), the present study studied the functional neuroanatomy of traumatic and non-traumatic emotional memory in two surgical patients who had sustained severe accident trauma. While patient 1 had developed acute PTSD following the traumatic event, patient 2 (control) did not. When confronted with traumatic (relative to negatively valenced non-traumatic) memory, the PTSD patient exhibited evidence for increased neural activity in the right and the left superior temporal lobe, the amygdala, the left angular gyrus, and the medial frontal gyrus, while the non-PTSD patient exposed to identical conditions showed increased activations in frontal and parietal regions. Both patients exhibited identical activation patterns when recalling non-traumatic memories relative to neutral memories. It is concluded that the pronounced activation patterns in the PTSD patient may be considered specific for acute PTSD, involved with the emotional arousal and the vivid visual recollections typical for the acute phase of the disorder.