Neurobehavioural changes in patients following brain tumour: patients and relatives perspective.

PURPOSE: Patients and relatives experiences of behavioural and personality changes following brain tumour were assessed to determine whether these changes are more prominent in the experience of patients with frontal tumours and their relatives as a first step to evaluate the need to develop appropriate support and management of such changes, which have a substantial impact on social functioning, and ultimately to improve quality of life. METHODS: Patients and relatives rated the patients' current levels of apathy, disinhibition and executive dysfunction on the Frontal Systems Behaviour Scale. Patients also completed the Hospital Anxiety and Depression Scale. The data from 28 patients with frontal tumours and 24 of their relatives, and 27 patients with nonfrontal tumours and 25 of their relatives, were analysed. RESULTS: Patients with frontal tumours rated themselves significantly higher than patients with nonfrontal tumours on all frontal systems-related behaviours. The number of patients reporting clinical levels of difficulty was significantly greater in patients with frontal tumours for disinhibition. The ratings of relatives of patients with frontal tumours were significantly higher than those of relatives of patients with nonfrontal tumours for apathy. Clinically significant levels of apathy and executive dysfunction were however reported by at least 40 % of patients and relatives regardless of tumour location. Clinical levels of anxiety were reported by significantly more patients with frontal tumours than those with nonfrontal tumours. CONCLUSION: Support and management of behavioural and personality change for patients with brain tumours and their relatives, regardless of tumour location, would be most appropriate.

Caffeine restores regional brain activation in acute hypoglycaemia in healthy volunteers.

AIMS: Caffeine enhances counterregulatory responses to acute hypoglycaemia. Our aim was to explore its effects on cortical function, which are not known at present. METHODS: Regional brain activation during performance of the four-choice reaction time (4CRT) at different levels of complexity was measured using functional magnetic resonance imaging (fMRI) at euglycaemia (5 mmol/l) and hypoglycaemia (2.6 mmol/l) in the presence and absence of caffeine in six healthy right-handed men. RESULTS: During hypoglycaemia, caffeine enhanced adrenaline responses to hypoglycaemia (2.5 +/- 0.7 nmol/l to 4.0 +/- 1.0 nmol/l, P = 0.01) and restored the brain activation response to the non-cued 4CRT, the linear increases in regional brain activation associated with increased task complexity and the ability to respond to a cue that were lost in hypoglycaemia alone. CONCLUSIONS: Caffeine can sustain regional brain activation patterns lost in acute hypoglycaemia, with some restoration of cortical function and enhanced adrenaline responsiveness. A methodology has been established that may help in the development of therapies to protect against severe hypoglycaemia in insulin therapy for patients with diabetes and problematic hypoglycaemia.

Differential effect of Huntington's and Parkinson's diseases in programming motor sequences of varied lengths.

BACKGROUND: Parkinson's disease (PD) and Huntington's disease (HD) patients have difficulties executing sequential movements. Attention control and short-term memory probably play an important role in programming sequential movements. To investigate the contribution of these cognitive factors to programming and executing visuomotor sequences in HD and PD patients a computerized version of the Corsi Block Tapping-Test was employed. METHODS: the performance of 11 patients with early stage PD, 11 HD patients with borderline to mild caudate atrophy and 20 healthy subjects was compared. The task was a reaction time task where targets were illuminated in groups of sequences increasing from 2 items to 5 items. Subjects reproduced the sequence (pressing the illuminated target) in the same order of appearance. Reaction Times and movement times were recorded. RESULTS: PD patients had increasing difficulties in programming and executing series greater than three components. HD patients did not differ significantly from the controls, although they showed a tendency to lose accuracy in the longer series. Both patient groups did not differ in their attention span. CONCLUSIONS: In PD although the spatial information may be well stored, they have difficulty accessing it when their attention is overloaded, leading to poor encoding and slow information processing. This process interferes with programming and execution of movement sequences. HD patients in the early stages of the illness seem to have more attention resources than PD patients, so that they start to show more problems in executing visuomotor sequences with longer movement sequences than PD patients.

Cognitive modulation of the cerebral processing of human oesophageal sensation using functional magnetic resonance imaging.

BACKGROUND: While cortical processing of visceral sensation has been described, the role that cognitive factors play in modulating this processing remains unclear. AIM: To investigate how selective and divided attention modulate the cerebral processing of oesophageal sensation. METHODS: In seven healthy volunteers (six males, mean age 33 years; ranging from 24 to 41 years old) from the general community, phasic visual and oesophageal (non-painful balloon distension) stimuli were presented simultaneously. During the selective attention task, subjects were instructed to press a button either to a change in frequency of oesophageal or visual stimuli. During a divided attention task, subjects received simultaneous visual and oesophageal stimuli and were instructed to press a button in response to a change in frequency of both stimuli. RESULTS: Selectively focussing attention on oesophageal stimuli activated the visceral sensory and cognitive neural networks (primary and secondary sensory cortices and anterior cingulate cortex respectively) while selective attention to visual stimuli primarily activated the visual cortex. When attention was divided between the two sensory modalities, more brain regions in the sensory and cognitive domains were utilised to process oesophageal stimuli in comparison to those employed to process visual stimuli (p=0.003). CONCLUSION: Selective and divided attention to visceral stimuli recruits more neural resources in both the sensory and cognitive domains than attention to visual stimuli. We provide neurobiological evidence that demonstrates the biological importance placed on visceral sensations and demonstrate the influence of cognitive factors such as attention on the cerebral processing of visceral sensation.

The effect of acute hypoglycemia on brain function and activation: a functional magnetic resonance imaging study.

The authors' aim was to examine the regional anatomy of brain activation by cognitive tasks commonly used in hypoglycemia research and to assess the effect of acute hypoglycemia on these in healthy volunteers. Eight right-handed volunteers performed a set of cognitive tasks-finger tapping (FT), simple reaction time (SRT), and four-choice reaction time (4CRT)-twice during blood oxygen level-dependent (BOLD) functional magnetic resonance imaging of the brain on two occasions. In study 1 (n = 6), plasma glucose was maintained at euglycemia (5 mmol/l) throughout. In study 2 (n = 6), plasma glucose was reduced to 2.5 mmol/l for the second set. Performance of the tasks resulted in specific group brain activation maps. During hypoglycemia, FT slowed (P = 0.026), with decreased BOLD activation in right premotor cortex and supplementary motor area and left hippocampus and with increased BOLD activation in left cerebellum and right frontal pole. Although there was no significant change in SRT, BOLD activation was reduced in right cerebellum and visual cortex. The 4CRT deteriorated (P = 0.020), with reduction in BOLD activation in motor and visual systems but increased BOLD signal in a large area of the left parietal association cortex, a region involved in planning. Hypoglycemia impairs simple brain functions and is associated with task-specific localized reductions in brain activation. For a task with greater cognitive load, the increased BOLD signal in planning areas is compatible with recruitment of brain regions in an attempt to limit dysfunction. Further investigation of these mechanisms may help devise rational treatment strategies to limit cortical dysfunction during acute iatrogenic hypoglycemia.

Motor learning by imagery is differentially affected in Parkinson's and Huntington's diseases.

Studies of motor imagery and motor learning have thus far been concerned only with its effects on healthy subjects. Therefore, in order to investigate the possible involvement of the basal ganglia, the effectiveness of motor imagery in the acquisition of motor constants in a graphomotor trajectorial learning task was examined in 11 non-demented mildly affected Huntington's disease (HD) patients and 12 non-demented Parkinson's disease (PD) patients. The patients received, after baseline, 10 min of motor imagery training, followed by a motor practice phase. Additionally, a test battery for visual imagery abilities was administered in order to investigate possible relations between visual and motor imagery. The results showed that imagery training alone enabled the HD patients to achieve a significant approach to movement isochrony, whereas the PD patients showed no marked improvements, either with motor imagery or with motor practice. Furthermore, the PD patients had more difficulties than the HD patients in solving the visual imagery tasks. Subsequent correlational analysis revealed significant relationships between the degree of caudate atrophy in the HD patients and their performance in the visual imagery tasks. However, there were no substantial correlations between the performance on the visual imagery tasks and the improvement of motor performance through motor imagery, which indicates that visual and motor imagery are independent processes. It is suggested that the dopaminergic input to the basal ganglia plays an important role in the translation of motor representations into motor performance, whereas the caudate nucleus atrophy of the HD patients does not seem to affect motor imagery, but only the visual imagery process. Furthermore, the deficits found in PD patients might also be related to their limited attentional resources and difficulties in employing predictive motor strategies.

A mental route to motor learning: improving trajectorial kinematics through imagery training.

There are contrasting reports upon the level of effectiveness of motor imagery in learning new motor skills, but there is general consensus that motor imagery can lead to improvements in performance, especially in combination with physical practice. In the present study we examined the effectiveness of motor imagery in the acquisition of movement invariants in two grapho-motor trajectorial learning tasks with differing visuospatial components: 'Ideogram drawing' and 'connecting circles'. Two subject groups were studied: An imagery group, which underwent 10 min of motor imagery training and a control group, which practised a control visuomotor task over the same period of time. The results showed that imagery training alone enabled the subjects to achieve a significant approach to movement isochrony as well as a significant shifting of peak velocity toward the target. After a practice phase, both groups improved their performance, but the imagery group was still significantly faster than the control group. Furthermore, a series of tests measuring visual imagery abilities was administered to the subjects. There were however no significant relationships between the motor performance and the visual imagery ability levels of the subjects. It is concluded that motor imagery can improve the acquisition of the spatio-temporal patterns of grapho-motor trajectories and that there are different processes involved in visual and motor imagery.

Representations of graphomotor trajectories in the human parietal cortex: evidence for controlled processing and automatic performance.

The aim of this study was to identify the cerebral areas activated during kinematic processing of movement trajectories. We measured regional cerebral blood flow (rCBF) during learning, performance and imagery of right-hand writing in eight right-handed volunteers. Compared with viewing the writing space, increases in rCBF were observed in the left motor, premotor and frontomesial cortex, and in the right anterior cerebellum in all movement conditions, and the increases were related to mean tangential writing velocity. No rCBF increases occurred in these areas during imagery. Early learning of new ideomotor trajectories and deliberately exact writing of letters both induced rCBF increases in the cortex lining the right intraparietal sulcus. In contrast, during fast writing of overlearned trajectories and in the later phase of learning new ideograms the rCBF increased bilaterally in the posterior parietal cortex. Imagery of ideograms that had not been practised previously activated the anterior and posterior parietal areas simultaneously. Our results provide evidence suggesting that the kinematic representations of graphomotor trajectories are multiply represented in the human parietal cortex. It is concluded that different parietal subsystems may subserve attentive sensory movement control and whole-field visuospatial processing during automatic performance.

Successive roles of the cerebellum and premotor cortices in trajectorial learning.

The structures of the human brain engaged during learning of unilateral trajectorial hand movements were mapped by measurements of regional cerebral blood flow. Trajectorial movement velocity accelerated moderately after short-term training p < 0.025 and increased further after long-term training p < 0.01. During the early phase of learning there was a significant activation p < 0.001 of the ipsilateral dentate nucleus. By contrast, after overlearning the premotor cortical areas in both cerebral hemispheres were maximally activated p < 0.001, while the dentate nucleus was no longer activated. It is suggested that learning of new movement trajectories involves the cerebellum, while overlearned trajectorial movements engage the premotor cortex.

[Prospective follow-up of neuropsychological deficits after cervicocephalic acceleration trauma]. / Prospektiver Verlauf neuropsychologischer Defizite nach zervikozephalem Akzelerationstrauma.

30 patients with acute cervico-cephalic syndrome following whiplash injury (neck and head pain, vegetative symptoms and subjective complaints of impaired mental functions) without neurological deficits were investigated in a prospective follow-up of 3 months with neuropsychological examination in the acute phase (x = 5.7 days) and again 6 and 12 weeks after the accident. Attention, concentration, cognition and verbal and visual memory functions were quantified by neuropsychological tests, and changes over the observation period were analysed. In the acute phase all neuropsychological functions were below the individual's normal level. Deficits in attention and concentration recovered within the first 6 weeks. Further recovery within the following 6 weeks were observed in visual memory, imagination and analytic capacity. The capability of verbal memory and abstraction, cognitive selectivity and information processing speed was impaired for a longer time and first recovered after 12 weeks. In conclusion, intraindividual neuropsychological deficits following whiplash injury can be quantified and monitored to show the time course of recovery. Thus in clinical and forensic practice the diagnosis of a pseudoneurasthenic or even "neurotic" syndrome in acute whiplash injury should be made with caution.