Krzysztof Jodzio

Neuropsychological differences between frontotemporal dementia and Alzheimer's disease: a review.

This paper surveys the similarities and differences between frontotemporal dementia (FTD) and Alzheimers disease (AD). The review covers findings primarily from neuropsychological studies on memory, language, attention/executive function, and visuospatial abilities. However, neuropsychiatric and neuroimaging data are also briefly discussed. Distinguishing features of both FTD and AD are described in order to present a comprehensive clinical picture of these dementing diseases, which is essential for the process of differential diagnosis. The cause of specific cognitive deficits is also considered. Our comprehensive review of the empirical literature reveals that AD is characterized by early memory loss and visuospatial problems, while among the main features of FTD are behavioral abnormalities and executive dysfunctions.

Defective comprehension of emotional faces and prosody as a result of right hemisphere stroke: modality versus emotion-type specificity.

Studies of patients with brain damage, as well as studies with normal subjects have revealed that the right hemisphere is important for recognizing emotions expressed by faces and prosody. It is unclear, however, if the knowledge needed to perform recognition of emotional stimuli is organized by modality or by the type of emotion. Thus, the purpose of this study is to assess these alternative a priori hypotheses. The participants of this study were 30 stroke patients with right hemisphere damage (RHD) and 31 normal controls (NC). Subjects were assessed with the Polish adaptation of the Right Hemisphere Language Battery of Bryan and the Facial Affect Recognition Test based on work of Ekman and Friesen. RHD participants were significantly impaired on both emotional tasks. Whereas on the visual-faces task the RHD subjects recognized happiness better than anger or sadness, the reverse dissociation was found in the auditory-prosody test. These results confirm prior studies demonstrating the role of the right hemisphere in understanding facial and prosodic emotional expressions. These results also suggest that the representations needed to recognize these emotional stimuli are organized by modality (prosodic-echoic and facial-eidetic) and that some modality specific features are more impaired than others.

Wisconsin Card Sorting Test as a Measure of Executive Function Impairments in Stroke Patients

The Wisconsin Card Sorting Test (WCST) is among the most frequently administered neuropsychological tests. It is assumed that successful completion of this test requires engagement of executive functions (EF). One of the most common origins of EF impairments is ischemic stroke. The present study intends to evaluate the diagnostic use of the WCST as a measure of these impairments in poststroke patients. Forty-four patients (8 women and 36 men) who had recent unilateral stroke (22 left hemisphere, 22 right hemisphere) participated in the study. The overall accuracy of the WCST in classifying stroke survivors as having executive disorders was poor. Nevertheless, statistical analysis revealed its negative predictive power to be greater than positive predictive power (i.e., normal scores on the WCST reliably indicated the absence of executive disorders in 8 or more out of 10). Performance on the WCST is clearly influenced by severity of the executive disorders. Namely, patients with severe impairment of EF (as measured by go/no-go, fluency, and other EF tests) performed more poorly on the WCST than patients with lesser impairment or those with no impairment at all, the latter groups results being indistinguishable. In addition, this study highlights a three-factor solution to the WCST, which accounted for 90.3% of the variance. The scores that most strongly loaded on Factors 1 to 3 were, in order: percentage of conceptual-level responses, number of trials to complete the first category, and failures to maintain the set of responses. Finally, an analysis using multivariate analysis of variance, with the anterior versus posterior site and left versus right side of the lesion as independent variables, revealed a relatively weak effect of lesion location on the WCST performance. In particular, with respect to all test scores, there is only one significant interaction between the site and side of lesion was obtained (F (1,24) = 4.12; p < .05; i.e., the number of categories achieved was significantly smaller after damage to the frontal lobe on the left than on the right side, whereas the laterality effect was not significant after nonfrontal lesions). In conclusion, to ascertain the cerebral substrates of poststroke executive dysfunction, there is a need to apply more accurate tests than the WCST. The study highlights the importance of a multicomponent approach to executive functioning in stroke patients.

The contribution of the left and right hemispheres to early recovery from aphasia: a SPECT prospective study.

This prospective study examined the relationship between post-stroke recovery of aphasia and changes in cerebral blood flow (CBF). To address the question of right hemisphere (RH) involvement in restitution of language, we tested the hypothesis that the increase in perfusion of the RH is crucial for early recovery from aphasia. Twenty-four right-handed patients with acute aphasia following left hemisphere (LH) ischaemic stroke were examined twice with a six-month interval. At each session CBF and language scores were measured on the same stroke patients. Language was measured by selected tasks derived from the Boston Diagnostic Aphasia Examination (BDAE). The SPECT scans were obtained using 99mTc-ECD on a triple-head gamma camera Multispect-3. Although initial CBF measured for the whole group of aphasic patients was not a predictor for future language recovery for either hemisphere, increased perfusion of the RH during a six-month interval was found to parallel the recovery of aphasic disorders. There was a correlation between the change in the right parietal CBF (but not the left) and a change in numerous language abilities. Nevertheless, only CBF values on the left predicted performance on the language tests at initial and follow-up examinations. When the area damaged on structural imaging was excluded from perfusion analysis, only subcortical CBF change on the left showed a positive correlation with language improvement. Thus, the cerebral mechanism associated with early recovery from aphasia is a dynamic and complex process that may involve both hemispheres. Probably this mechanism involves functional reorganisation in the speech-dominant (damaged) hemisphere and regression of haemodynamic disturbances in the non-dominant (structurally intact) hemisphere.

Understanding the Physiopathology Behind Axial and Radial Diffusivity Changes—What Do We Know?

The use of the diffusion tensor imaging (DTI) is rapidly growing in the neuroimaging field. Nevertheless, rigorously performed quantitative validation of DTI pathologic metrics remains very limited owing to the difficulty in co-registering quantitative histology findings with magnetic resonance imaging. The aim of this review is to summarize the existing state-of-the-art knowledge with respect to axial (λ║) and radial (λ┴) diffusivity as DTI markers of axonal and myelin damage, respectively. First, we provide technical background for DTI and briefly discuss the specific organization of white matter in bundles of axonal fibers running in parallel; this is the natural target for imaging based on diffusion anisotropy. Second, we discuss the four seminal studies that paved the way for considering axial (λ║) and radial (λ┴) diffusivity as potential in vivo surrogate markers of axonal and myelin damage, respectively. Then, we present difficulties in interpreting axial (λ║) and radial (λ┴) diffusivity in clinical conditions associated with inflammation, edema, and white matter fiber crossing. Finally, future directions are highlighted. In summary, DTI can reveal strategic information with respect to white matter tracts, disconnection mechanisms, and related symptoms. Axial (λ║) and radial (λ┴) diffusivity seem to provide quite consistent information in healthy subjects, and in pathological conditions with limited edema and inflammatory changes. DTI remains one of the most promising non-invasive diagnostic tools in medicine.

Compensatory functional reorganization may precede hypertension-related brain damage and cognitive decline: a functional magnetic resonance imaging study.

Objectives: Our study aimed at exploring structural and functional differences in the brain during higher cognitive processing between middle-aged hypertensive patients and controls matched for sex, age and years of education. Methods: Two groups of 20 patients took part in MRI examinations. This article reports the results of functional MRI during a Stroop color interference task and structural evaluations based on a modified Fazekas scale. Results: No intergroup differences were found in regards to the severity of white matter lesions (Mann–Whitney U test = 150.5, P > 0.1), nor from the task performance in the scanner (t(35) = 0.2, P > 0.1). However, brain activation patterns between patients and controls varied. Hypertensive patients involved significantly more cerebral areas during the processing, regardless of the task difficulty. Differences were found in 26 diverse regions of both primary and associative cortices (with a peak voxel located in the cuneus, Z = 6.94, P < 0.05 family-wise error corrected at voxel level). Conclusion: Our findings provide an insight into the brain mechanisms related to essential hypertension and suggest a functional reorganization (neuroplasticity) early in the course of the disease.

Imaging Techniques for the Detection and Diagnosis of Brain Damage in Hypertension

Hypertension is the major causal factor of neurovascular pathology including both vascular and parenchymal lesions. These lesions are the consequence of large vessel and small vessel ischaemic infarctions, macrohaemorrhages and microbleeds (MBs), as well as vascular and parenchymal brain alterations leading to cerebral tissue disintegration and secondary effects on brain metabolism and function. This chapter includes a description of the images of different brain lesions, silent and clinical, induced by hypertension. Also recent advances in functional neuroimaging for characterizing the effects of hypertension on the brain integrity are described.

31-YEAR-OLD MAN WITH BALINT'S SYNDROME AND VISUAL PROBLEMS

A 31-year-old man presented with Balint’s syndrome. Radiology studies suggested an inflammatory demyelinating process within the occipital and parietal lobes. A cystic sellar/suprasellar mass was also found. Neuroimaging 2.5 years later showed progression of the lesions and growth of the tumor. Based on elevated antimeasles antibody titers in the cerebrospinal fluid subacute sclerosing panencephalitis (SSPE) was diagnosed. After 4 years of disease the patient died in a decerebrate state with tetraparesis. Neuropathological examination showed brain atrophy with discoloration and irregular induration of the white matter. The sellar tumor was a craniopharyngioma. Microscopically a chronic and active panencephalitis was revealed with intranuclear inclusions. Ultrastructural examination confirmed SSPE by demonstrating measles virus nucleocapsids within the inclusions. SSPE is a rare progressive neurological disorder caused by persistent defective measles virus infection and is usually seen in children and young adults. This disease has been eradicated in many countries by obligatory immunization. This case demonstrates, however, that SSPE should still be considered in the neurological and neuropathological differential diagnoses even in adult patients. Furthermore this is a first reported case of SSPE coexisting with a brain tumor (craniopharyngioma). Correspondence 530 Brain Pathology 19 (2009) 527–530