No abstract

Tourette's syndrome and Huntington's disease have long been clinically associated with attentional deficits. In this study, we aimed to determine the nature and quantify the extent of such deficits. A technique was devised to ascertain the efficiency with which Tourette's syndrome and Huntington's disease patients could shift and direct attention away from naturally expected stimulus-response (S-R) linkages. This was done by varying the relationships formed between stimulus and response location. Attentional efficiency was indicated by relative speed of responding to relevant (congruent) and irrelevant (incongruent) stimuli, in a paradigm developed from the Simon effect. There were five conditions progressively increasing in complexity. The stimuli consisted of left and right pointing arrows and, in some cases, various conditionality manipulations were also employed, such that in the presence of a certain symbol (i.e. 'x') the nature of the response had to be reversed, whereas in the presence of an alternative symbol (i.e. '='), the response was compatible with the direction of the arrow. As predicted, Tourette's syndrome and Huntington's disease patients, regardless of medication or depression status and unlike controls, were particularly disadvantaged in responding to various conflicting S-R configurations. Tourette's syndrome and Huntington's disease patients may experience difficulties in making attentional shifts, or in inhibiting inappropriate responses; they may also be more susceptible (than controls) to the conflict that can arise when the spatial code formed for the stimulus is irrelevant for selecting the appropriate response. We conclude that our findings support the notion that cognitive deficits in Tourette's syndrome and Huntington's disease may stem from abnormalities of the major pathways interconnecting the basal ganglia and the frontal lobes.

Recent research has shown that Huntington's disease (HD) causes problems in the initiation and execution of movement (akinesia, bradykinesia): information which is useful in documenting the functional progression of the disease. The present experiment used a sequential movement task to characterize such impairments. Eighteen patients diagnosed as suffering from HD, and a similar number of matched At-Risk (AR) and Normal control subjects, performed sequential button pressing tasks, under varying amounts of visual advance information. Specific dimensions of motor control were examined (hand, direction). Movement initiation and in particular movement duration were useful indicators of the functional progression of the disease, and also detected anomalies of performance in some AR individuals. Impaired motor programming was indicated by patients' difficulty in initiating movements in the absence of external visual cues, and their problems in utilizing advance information to control movement. Patients had specific deficits in initiating movements with the nonpreferred hand, and directional movement asymmetries were accentuated. The results suggest that HD causes difficulties at three discrete levels: in utilizing advance information, in the initiation and in the spatial representation of movement.

Patients with Huntington's disease exhibit poorer-quality handwriting, sometimes clinically exhibiting macrographia, an increase in the size of handwriting. To characterize deficits in handwriting of patients with Huntington's disease, we compared the writing of 12 young, 12 age-matched controls, and 12 patients with Huntington's disease. Subjects were asked to write the letter "l" four times, at a constant length, on a graphics tablet that sampled pen position at 200 Hz. Huntington's disease causes chorea (involuntary movement), akinesia (difficulty in initiating voluntary movement), and bradykinesia (slowness and difficulty in maintaining voluntary movement). To distinguish changes in handwriting quality due to involuntary movement from impairments of voluntary movement, handwriting samples with obvious choreic movements were analyzed separately from other handwriting samples. Several measures of quality of handwriting were considered, based on: the regularity and consistency of handwriting, the efficiency of movement trajectories, and the proportions of movement occurring at specific frequencies. Results suggested that Huntington's disease increases variability of movement parameters, and causes problems in producing smooth movements. Choreic movement was best characterized by the number of zero crossings in the velocity function relative to the prescribed number of writing strokes. We hypothesize that macrographia in Huntington's disease occurs when chorea predominates over bradykinesia. Comparisons were made between the handwriting of patients with Huntington's and Parkinson's diseases.

In the last years the studies regarding the biocompatibility of dental materials investigate, in addition to the classic cytotoxic tests, the interactions between the materials and the host cells to better explain the causes of the adverse effects observed sometimes in the clinical practice. In the present study the ability of diurethane dimethacrylate (DUDMA) and 1,4‐butanediol dimethacrylate (BDDMA) methacrylic monomers present in dental composite resins to alter the functionality of peripheral blood monocytes (PBMs) and polymorphonucleate cells (PMNs) was examined. These cells are involve in the biological response to materials and in the host ability to respond to bacteria. The results obtained suggest that the examined methacrylates induce a relevant decrease of PBMs oxidative burst whereas the basal ROS production is only slightly decreased. In PMNs DUDMA induces a decrease of both basal and stimulated ROS production. BDDMA, on the contrary, it does not alter total oxidative burst in presence of stimulus while induces a statistically significant decrease of basal ROS production. Moreover this monomer alters the reaction kinetics of stimulated ROS production. The reported finding seems to indicate that this molecule could be able to stabilize PMNs in resting state and maximize their stimulated activity. Copyright © 2008 John Wiley & Sons, Ltd.

Tourette's syndrome is a chronic neurological disorder manifested by involuntary motor tics and vocalisations.

Current symptomatic treatments for dementia have only modest efficacy. Assessing meaningful benefits in this variably progressive syndrome is complex and difficult. This consensus statement was generated by an international group representing caregivers, organizations and professionals with expertise in dementia. We recommend the statement of clear, pre-defined diagnostic and severity criteria and outcome measures, which include functional and executive capacity, in treatment trials. Outcomes can include effects on people with dementia (PWD) with regard to cognition, behavioral and psychological symptoms, quality of life, global assessments, and activities of daily living, and must be tailored to the education and culture of the participants. Outcomes can also appropriately encompass effects on caregivers. New instruments may be needed, as validation of many existing measures has been in relatively homogenous populations. Treatment goals can be to prevent dementia emerging, or in those with established dementia to slow deterioration, and to postpone, stabilize or improve symptoms. Comparisons between treatment groups should be on the basis of clinically relevant measures with both risk and benefit reported for all participants regardless of whether or not they continue to receive treatment throughout the trial. Characterization of any groups that respond well to treatment has been unsuccessful to date, but may be facilitated in the future by measurement of putative biomarkers. Despite considerable recent progress and several 'candidate' biomarkers, none is yet satisfactory for determining diagnosis, severity, progression or prediction of response. To provide meaningful data, economic analyses should use up-to-date, country-specific data. Health economic measures should be incorporated as secondary outcomes in all Phase 3 trials since health systems are concerned with cost-effectiveness as well as clinical outcome. Health utility measures are not, however, validated satisfactorily in dementia, thus calling into question previous health economic analyses. While current drugs appear to reduce the amount of family caregiver time required by PWD, these costs fall in the main on older individuals who often exert little political leverage, rather than on society at large. Traditionally, elderly people have been marginalized in the political process. The growth in the older population across the world, and their potential for increasing political empowerment may lead to a radical re-evaluation of the economics of treatment in dementia.

To identify the focus of impairment in the performance of sequential movements in Huntington's disease (HD) patients, the extent of their reliance on external advance information was examined. Twelve patients with HD and their age-matched controls performed a series of button-presses at sequential choice points along a response board. A sequential pathway was designated, and with each successive button press, advance visual information was systematically reduced to various extents in advance of each move. HD patients, like previously studied parkinsonian patients, were particularly disadvantaged with high levels of reduction in advance information, and as a consequence, both their initiation and execution of movements progressively slowed with each successive element in the response sequence. The pattern of results was not affected whether or not patients were taking neuroleptic medication, nor did performance on a variety of cognitive measures correlate with motor performance. Control subjects' performance, on the other hand, remained constant in terms of both initiation and execution with each of the three levels of reduction in advance information. We conclude that HD patients, like parkinsonian patients, who also suffer from a basal ganglia (BG) disorder, require external visual cues to sequence motor programs effectively. Our findings suggest that with HD there may be abnormalities in a central mechanism that controls switching between movement segments within an overall motor plan. The BG, which provide internal cues necessary for component sequencing, may be disrupted, thereby impairing the ability to use such internally generated cues to guide movement.