Structural white matter abnormalities in patients with idiopathic dystonia

We investigated whether structural white matter abnormalities, in the form of disruption of axonal coherence and integrity as measured with diffusion tensor imaging (DTI), constitute an underlying pathological mechanism of idiopathic dystonia (ID), independent of genotype status. We studied seven subjects with ID: all had cervical dystonia as their main symptom (one patient also had spasmodic dysphonia and two patients had concurrent generalized dystonia, both DYT1‐negative). We compared DTI MR images of patients with 10 controls, evaluating differences in mean diffusivity (MD) and fractional anisotropy (FA). ID was associated with increased FA values in the thalamus and adjacent white matter, and in the white matter underlying the middle frontal gyrus. ID was also associated with increase in MD in adjacent white matter to the pallidum and putamen bilaterally, left caudate, and in subcortical hemispheric regions, including the postcentral gyrus. Abnormal FA and MD in patients with ID indicate that abnormal axonal coherence and integrity contribute to the pathophysiology of dystonia. These findings suggest that ID is not only a functional disorder, but also associated with structural brain changes. Impaired connectivity and disrupted flow of information may contribute to the impairment of motor planning and regulation in dystonia. © 2006 Movement Disorder Society     

Effect of bite tray impression technique on relocation accuracy in frameless stereotactic radiotherapy.

A previously developed method for achieving patient relocation in fractionated stereotactic radiotherapy (attachment of an infrared fiducial system to a bite tray) relies on the integrity of a bite tray system that incorporates moulding to the patient's upper dentition. Reproducible and accurate patient positioning requires stability of the bite tray and mould during the full treatment process, both during the time the bite tray is inserted in the patient's mouth, and between separate bite tray insertions. The optimum construction method for a stable reproducible tray has not been sufficiently investigated. We undertook a study to identify factors which might influence the integrity of the hard palate bite tray system. Reprosil Fast Set Putty was used to construct 3 impression conditions; teeth only; teeth and alveolar sulcus; and teeth, alveolar sulcus, and the hard palate. Reproducibility was assessed by volunteers inserting the impressions multiple times and recording the locations of 8 standard reference points. Our results showed the optimal impression technique (i.e., the one that led to the smallest ranges in positional and rotational errors) was that which incorporated the teeth, alveolar sulcus, and hard palate.     

Children: Rights, education and equal opportunity

The point of departure in this paper is the concept of RIGHTS. Whereas most countries accept that children have rights as is evidenced in the UNO Declaration of Rights of the Child (1959), such rights are statements, not laws. Statements advocating benefits, care, love, education etc. are goals or beliefs. Few countries have legalised rights; consequently, children may be at risk. In countries where there is discrimination of some degree in respect of race, colour, sex, religion, national or social origin, financial standing in society, level of education and so on, the right to “rights” as stated in the UNO Declaration is further jeopardised. The implications for educational provision from early childhood and onwards in countries where “rights” are not entrenched in statutes or where child advocacy is not forceful enough for all people are examined in this paper. Consequently, the chances for equal opportunity in life are reduced in situations where the child did not receive the benefit of education. Such a child may not perish as he might as a result of being deprived of food, but “the deprivation and injustice, the degradation of an individual and the setting of his vital interests at naught would at least approach in gravity the act of allowing him to die for the want of food” (1981, Wringe). In this paper, the author argues for the Rights of the Child, particularly where discrimination and inequalities exist and where provision for early education has to contend with excessive population growth.     

L/M speed-matching ratio predicts reading in children.

PURPOSE: Many behavioral studies have found impaired perception of dynamic visual stimuli in dyslexia and several neuroimaging studies have found reduced activation of the human motion area MT+ in dyslexia. These results are often interpreted as a magnocellular (MC) deficit in dyslexia. It has also been claimed that colored filters can help dyslexics to read. One defining feature of the MC-pathway is a greater weight for L-cone input than M-cone input, and at most very weak S-cone input. We measured the subjective speed matches between L-, M-, and S-cone isolating stimuli in good and poor readers. METHODS: Subjects performed a speed-matching task with drifting cone-isolating stimuli to find the point of subjective equality between two drifting patterns. Such a task is known to activate cortical area MT+, presumably via the MC-pathway. RESULTS: L- to M-cone speed-match ratios were negatively correlated with single-word (r=-0.46) and irregular-word reading (r=-0.56) but not with non-word reading. CONCLUSIONS: Results suggest that relative L-cone sensitivity within the MC-pathway may limit orthographic reading performance.     

Local anaesthesia in elective inguinal hernia repair: a randomised, double-blind study comparing the efficacy of levobupivacaine with racemic bupivacaine.

OBJECTIVE: To assess the use of infiltration with local anaesthetics levobupivacaine and bupivacaine, during inguinal hernia repair. DESIGN: Double-blind, randomised study. SETTING: Postgraduate medical school, United Kingdom. SUBJECTS: 69 male patients aged 18 years or older. INTERVENTIONS: Wound infiltration with 0.25% levobupivacaine and 0.25% racemic bupivacaine. MAIN OUTCOME MEASURES: Area under the curve (AUC) of visual analogue scale (VAS) scores for postoperative pain at rest in the supine position, rising from the supine to the sitting position, and walking, against time for both treatment groups. RESULTS: There were no significant differences between treatment groups for the AUC of VAS scores for postoperative pain, global verbal pain rating or time to first dose of analgesic medication. CONCLUSIONS: Levobupivacaine exerts a similar anaesthetic and analgesic effect to racemic bupivacaine when infiltrated both intraoperatively and during the early postoperative period for elective inguinal hernia repair.