Neuropsychological assessment of an eighty-nine year old man

A case of first onset of the symptoms of mania in an eighty-nine year old man is reported. Organic contributions appear to be particularly important in cases of mania in older adults. In cases of first onset of mania in older adults the major differential diagnosis is between primary mania and a wide range of possible secondary etiological factors. This man had no known history of affective disorder and at the time of initial examination no organic explanation for his symptoms could be identified. While lateonset bipolar disorder has been reported in the literature, such cases are rare and are usually proceeded by a history of major depressive disorder or dysthymia. A range of neuropsychological assessment instruments were administered as part of a comprehensive inpatient examination of this man, commenting on his cognitive functioning and competence to manage his affairs. This assessment indicated that while his functioning was intact in some areas, there were areas of significant difficulty. The case illustrates the difficulties in interpreting neuropsychological assessment results obtained during a manic phase, and highlights some of the difficulties of conducting research with older adults.

Progressive loss of expressive language in a journalist: What news for dementia?

A 77-year-old man with 8 year progressive language deterioration in the face of grossly intact memory was followed. No acute or chronic physiological or psychological event was associated with symptom onset. CT revealed small left basal ganglia infarct. Mild atrophy, no lacunar infarcts, mild diffuse periventricular changes registered on MRI. Gait normal but slow. Speech hesitant and sparse. Affect euthymic; neurobehavioral disturbance absent. MMSE 26/30; clock incorrect, concrete. Neuropsychological testing revealed simple attention intact; complex attention, processing speed impaired. Visuospatial copying and delayed recall of copy average with some perseveration. Apraxia absent. Recall mildly impaired. Mild deficits in planning, organization apparent. Patient severely aphasic, dysarthric without paraphasias. Repetition of automatic speech, recitation moderately impaired; prosody intact. Understanding of written language, nonverbal communication abilities, intact. Frontal release signs developed over last 12 months. Repeated cognitive testing revealed mild deterioration across all domains with significant further decrease in expressive, receptive language. Neurobehavioral changes remain absent to date; he remains interested, engaged and independent in basic ADLs. Speech completely deteriorated; gait and movements appreciably slowed. Although signs of frontal/executive dysfunction present, lack of behavioral abnormalities, psychiatric disturbance, personality change argue against focal or progressive frontal impairment or dementia. Relative intactness of memory and comprehension argue against Alzheimer’s disease. Lack of findings on neuroimaging argue against CVA or tumor. It is possible that the small basal ganglia infarct has resulted in a mild lateral prefrontal syndrome. However, the absence of depression as well as the relatively circumscribed language problem suggests otherwise. The progressive, severe nature of language impairments, with relatively minor impairments in attention and memory, argues for a possible diagnosis of primary progressive aphasia.

Symptoms of hyperactivity and inattention can mediate deficits of postural stability in developmental dyslexia

DDevelopmental dyslexia is a reading disorder associated with impaired postural control. However, such deficits are also found in attention deficit hyperactivity disorder (ADHD), which is present in a substantial subset of dyslexia diagnoses. Very few studies of balance in dyslexia have assessed ADHD symptoms, thereby motivating the hypothesis that such measures can account for the group differences observed. In this study, we assessed adults with dyslexia and similarly aged controls on a battery of cognitive, literacy and attention measures, alongside tasks of postural stability. Displacements of centre of mass to perturbations of posture were measured in four experimental conditions using digital optical motion capture. The largest group differences were obtained in conditions where cues to the support surface were reduced. Between-group differences in postural sway and in sway variability were largely accounted for by co-varying hyperactivity and inattention ratings, however. These results therefore suggest that postural instability in dyslexia is more strongly associated with symptoms of ADHD than to those specific to reading impairment.

Are poor mathematics skills associated with visual deficits in temporal processing?

Developmental learning disabilities such as dyslexia and dyscalculia have a high rate of co-occurrence in pediatric populations, suggesting that they share underlying cognitive and neurophysiological mechanisms. Dyslexia and other developmental disorders with a strong heritable component have been associated with reduced sensitivity to coherent motion stimuli, an index of visual temporal processing on a millisecond time-scale. Here we examined whether deficits in sensitivity to visual motion are evident in children who have poor mathematics skills relative to other children of the same age. We obtained psychophysical thresholds for visual coherent motion and a control task from two groups of children who differed in their performance on a test of mathematics achievement. Children with math skills in the lowest 10% in their cohort were less sensitive than age-matched controls to coherent motion, but they had statistically equivalent thresholds to controls on a coherent form control measure. Children with mathematics difficulties therefore tend to present a similar pattern of visual processing deficit to those that have been reported previously in other developmental disorders. We speculate that reduced sensitivity to temporally defined stimuli such as coherent motion represents a common processing deficit apparent across a range of commonly co-occurring developmental disorders.

Deficits in dyslexia:Barking up the wrong tree?

Reviews of the dyslexia literature often seem to suggest that children with dyslexia perform at a lower level on almost any task. Richards et al. (Dyslexia 2002; 8: 1-8) note the importance of being able to demonstrate dissociations between tasks. However, increasingly elegant experiments, in which dissociations are found, almost inevitably find that the performance of children with dyslexia is lower as tasks become more difficult! By looking for deficits in dyslexia, could we be barking up the wrong tree? A methodological approach for circumventing this potential problem is discussed. Copyright © 2004 John Wiley & Sons, Ltd.

Attention deficits in dyslexia:Evidence for an automatisation deficit?

Both attentional difficulties and rapid processing deficits have recently been linked with dyslexia. We report two studies comparing the performance of dyslexic and control teenagers on attentional tasks. The two studies were based on two different conceptions of attention. Study 1 employed a design that allowed three key components of attention - focusing, switching, and sustaining - to be investigated separately. One hypothesis under investigation was that rapid processing problems - in particular impaired ability to switch attention rapidly - might be associated with dyslexia. However, although dyslexic participants were significantly less accurate than their controls in a condition where they had to switch attention between two target types, the nature of the deficit suggested that the problem was not in switching attention per se. Thus, in Study 2, we explored an alternative interpretation of the Study 1 results in terms of the classic capacity-limited models of "central" attention. We contrasted two hypotheses: (1) that dyslexic teenagers have reduced cognitive resources versus (2) that they suffer from a general impairment in the ability to automatise basic skills. To investigate the automaticity of the shape recognition component of the task a similar attention paradigm to that used in Study 1 was employed, but using degraded, as well as intact, stimuli. It was found that stimulus degradation led to relatively less impairment for dyslexic than for matched control groups. The results support the hypothesis that dyslexic people suffer from a general impairment in the ability to automatise skills - in this case the skill of automatic shape recognition.

Pentoxifylline and the behaviour of 29-month female mice

The dimethyl-xanthine derivative pentoxifylline (PTX) increases blood flow through capillaries. In elderly humans the drug leads to improvement in a number of imapired neuropsychological parameters. We now report that oral administration to 29-month female mice (C57, black and tan) over six days induced four different patterns of behavioural reponse: (1) consistent improvement in grooming behaviour throughout the six day trial; (2) significant improvement in light/dark zone curiosity and curiosity towards a strange object on day three, which declined but remained significantly above pre-treatment levels at day 6; (3) an improvement in general activity which only becomes detectable on day six; (4) a significant improvement in rod-walking, rearing an shuttle-box crosses on day three which returned to pre-treatment levels by day 6. Age-related deficits in general activity, grooming and curiosity were completely eliminated by the drug - the mean group performance levels attained those seen in 9-12 month individuals of this strain.

On the interaction between perceptual and response selection: neuropsychological evidence

We examined the relations between selection for perception and selection for action in a patient FK, with bilateral damage to his temporal and medial frontal cortices. The task required a simple grasp response to a common object (a cup) in the presence of a distractor (another cup). The target was cued by colour or location, and FK made manual responses. We examined the effects on performance of cued and uncued dimensions of both the target and the distractor. FK was impaired at perceptually selecting the target when cued by colour, when the target colour but not its location changed on successive trials. The effect was sensitive to the relative orientations of targets and distractors, indicating an effect of action selection on perceptual selection, when perceptual selection was weakly instantiated. The dimension-specific carry-over effect on reaching was enhanced when there was a temporal delay between a cue and the response, and it disappeared when there was a between-trial delay. The results indicate that perceptual and action selection systems interact to determine the efficiency with which actions are selected to particular objects.

The anatomical and functional correlates of category-specificity

The dramatic effects of brain damage can provide some of the most interesting insights into the nature of normal cognitive performance. In recent years a number of neuropsychological studies have reported a particular form of cognitive impairment where patients have problems recognising objects from one category but remain able to recognise those from others. The most frequent ‘category-specific’ pattern is an impairment identifying living things, compared to nonliving things. The reverse pattern of dissociation, i.e., an impairment recognising and naming nonliving things relative to living things, has been reported albeit much less frequently. The objective of the work carried out in this thesis was to investigate the organising principles and anatomical correlates of stored knowledge for categories of living and nonliving things. Three complementary cognitive neuropsychological research techniques were employed to assess how, and where, this knowledge is represented in the brain: (i) studies of normal (neurologically intact) subjects, (ii) case-studies of neurologically impaired patients with selective deficits in object recognition, and (iii) studies of the anatomical correlates of stored knowledge for living and nonliving things on the brain using magnetoencephalography (MEG). The main empirical findings showed that semantic knowledge about living and nonliving things is principally encoded in terms of sensory and functional features, respectively. In two case-study chapters evidence was found supporting the view that category-specific impairments can arise from damage to a pre-semantic system, rather than the assumption often made that the system involved must be semantic. In the MEG study, rather than finding evidence for the involvement of specific brain areas for different object categories, it appeared that, when subjects named and categorised living and nonliving things, a non-differentiated neural system was involved.