A medial to lateral shift in pre-movement cortical activity in hemi-Parkinson's disease

Objective: Recent evidence suggests that cortical activity associated with voluntary movement is relatively shifted from medial to lateral premotor areas in Parkinson's disease. This shift occurs bilaterally even for unilateral responses. It is not clear whether the shift in processing reflects an overall change in movement strategy, thereby involving alternate cortical areas, or reflects a compensatory change whereby, given the appropriate conditions, less impaired cortical areas are able to provide a similar function in compensation for those areas which are more impaired. This issue was examined in patients with hemi-Parkinson's disease, in whom basal ganglia impairment is most pronounced in one hemisphere. Methods: Fourteen patients with hemi-Parkinson's disease and 15 age-matched control subjects performed a Go/NoGo finger movement task and the contingent negative variation (CNV) was recorded from 21 scalp positions. Results and conclusions: Maximal CNV amplitudes were found over central medial regions for control subjects, but were shifted more frontally for Parkinson's disease patients, reduced in amplitude over the midline and lateralized towards the side ipsilateral to the greatest basal ganglia impairment. This shift in cortical activity from medial to lateral areas in Parkinson's disease patients appears to reflect a compensatory mechanism operating predominantly on the side of greatest basal ganglia impairment. (C) 2001 Elsevier Science Ireland Ltd. All rights reserved.

Perturbed upper limb movements cause short-latency postural responses in trunk muscles

Addition of a load to a moving upper limb produces a perturbation of the trunk due to transmission of mechanical forces. This experiment investigated the postural response of the trunk muscles in relation to unexpected limb loading. Subjects performed rapid, bilateral shoulder flexion in response to a stimulus. In one third of trials, an unexpected load was added bilaterally to the upper limbs in the first third of the movement. Trunk muscle electromyography, intra-abdominal pressure and upper limb and trunk motion were measured. A short-latency response of the erector spinae and transversus abdominis muscles occurred similar to 50 ms after the onset of the limb perturbation that resulted from addition of the load early in the movement and was coincident with the onset of the observed perturbation at the trunk. The results provide evidence of initiation of a complex postural response of the trunk muscles that is consistent with mediation by afferent input from a site distant to the lumbar spine, which may include afferents of the upper limb.

Movement-related potentials in Huntington's disease: movement preparation and execution

Movement-related potentials (MRPs) reflect increasing cortical activity related to the preparation and execution of voluntary movement. Execution and preparatory components may be separated by comparing MRPs recorded from actual and imagined movement. Imagined movement initiates preparatory processes, but not motor execution activity. MRPs are maximal over the supplementary motor area (SMA), an area of the cortex involved in the planning and preparation of movement. The SMA receives input from the basal ganglia, which are affected in Huntington's disease (HD), a hyperkinetic movement disorder. In order to further elucidate the effects of the disorder upon the cortical activity relating to movement, MRPs were recorded from ten HD patients, and ten age-matched controls, whilst they performed and imagined performing a sequential button-pressing task. HD patients produced MRPs of significantly reduced size both for performed and imagined movement. The component relating to movement execution was obtained by subtracting the MRP for imagined movement from the MRP for performed movement, and was found to be normal in HD. The movement preparation component was found by subtracting the MRP found for a control condition of watching the visual cues from the MRP for imagined movement. This preparation component in HD was reduced in early slope, peak amplitude, and post-peak slope. This study therefore reported abnormal MRPs in HD. particularly in terms of the components relating to movement preparation, and this finding may further explain the movement deficits reported in the disease.

Contraction of the pelvic floor muscles during abdominal maneuvers

Objective: To determine whether voluntary abdominal muscle contraction is associated with pelvic floor muscle activity. Design: Pelvic floor muscle activity was recorded during contractions of the abdominal muscles at 3 different intensities in supine and standing positions. Setting: Research laboratory. Participants: Six women and 1 man with no histories of lower back pain. Interventions: Not applicable. Main Outcome Measures: Electromyographic activity of the pelvic floor muscles was recorded with surface electrodes inserted into the anus and vagina. These recordings were corroborated by measurements of anal and vaginal pressures. Gastric pressure was recorded in 2 subjects. Results: Pelvic floor muscle electromyography increased with contraction of the abdominal muscles. With strong abdominal contraction, pelvic floor muscle activity did not differ from that recorded during a maximal pelvic floor muscle effort. The pressure recordings confirmed these data. The increase in pressure recorded in the anus and vagina preceded the pressure in the abdomen. Conclusions: In healthy subjects, voluntary activity in the abdominal muscles results in increased pelvic floor muscle activity. The increase in pelvic floor pressure before the increase in the abdomen pressure indicates that this response is preprogrammed. Dysfunction of the pelvic floor muscles can result in urinary and fecal incontinence. Abdominal muscle training to rehabilitate those muscles may be useful in treating these conditions.

Motor imagery in Parkinson's disease: A PET study

We used positron emission tomography (PET) with O-15-labelled water to record patterns of cerebral activation in six patients with Parkinson's disease (PD), studied when clinically off and after turning on as a result of dopaminergic stimulation. They were asked to imagine a Finger opposition movement performed with their right hand. externally paced at a rate of 1 Hz. Trials alternating between motor imagery and rest were measured. A pilot study of three age-matched controls was also performed. We chose the task as a robust method of activating the supplementary motor area (SMA), defects of which have been reported in PD. The PD patients showed normal de-rees of activation of the SMA (proper) when both off and on. Significant activation with imagining movement also occurred in the ipsilateral inferior parietal cortex (both off and when on) and ipsilateral premotor cortex (when off only). The patients showed significantly greater activation of the rostral anterior cingulate and significantly less activation of the left lingual gyrus and precuneus when performing the task on compared with their performance when off. PD patients when imagining movement and off showed less activation of several sites including the right dorsolateral prefrontal cortex (DLPFC) when compared to the controls performing the same task. No significant differences from controls were present when the patients imagined when on. Our results are consistent with other studies showing deficits of pre-SMA function in PD with preserved function of the SMA proper. In addition to the areas of reduced activation (anterior cingulate, DLPFC), there were also sites of activation (ipsilateral premotor and inferior parietal cortex) previously reported as locations of compensatory overactivity for PD patients performing similar tasks. Both failure of activation and compensatory changes a-re likely to contribute to the motor deficit in PD. (C) 2001 Movement Disorder Society.

The preparation and execution of self-initiated and externally-triggered movement: A study of event-related fMRI

Studies of functional brain imaging in humans and single cell recordings in monkeys have generally shown preferential involvement of the medially located supplementary motor area (SMA) in self-initiated movement and the lateral premotor cortex in externally cued movement. Studies of event-related cortical potentials recorded during movement preparation, however, generally show increased cortical activity prior to self-initiated movements but little activity at early stages prior to movements that are externally cued at unpredictable times. In this study, the spatial location and relative timing of activation for self-initiated and externally triggered movements were examined using rapid event-related functional MRI. Twelve healthy right-handed subjects were imaged while performing a brief finger sequence movement (three rapid alternating button presses: index-middle-index finger) made either in response to an unpredictably timed auditory cue (between 8 to 24 s after the previous movement) or at self-paced irregular intervals. Both movement conditions involved similar strong activation of medial motor areas including the pre-SMA, SMA proper, and rostral cingulate cortex, as well as activation within contralateral primary motor, superior parietal, and insula cortex. Activation within the basal ganglia was found for self-initiated movements only, while externally triggered movements involved additional bilateral activation of primary auditory cortex. Although the level of SMA and cingulate cortex activation did not differ significantly between movement conditions, the timing of the hemodynamic response within the pre-SMA was significantly earlier for self-initiated compared with externally triggered movements. This clearly reflects involvement of the pre-SMA in early processes associated with the preparation for voluntary movement. (C) 2002 Elsevier Science.

A medial to lateral shift in premovement cortical activity in hemi-Parkinson's disease: Studies of event-related potentials and whole-scalp magneto encephalography

Cortical activity associated with voluntary movement is shifted from medial to lateral premotor areas in Parkinson's disease. This occurs bilaterally, even for unilateral movements. We have used both EEG and MEG to further investigate medial and lateral premotor activity in patients with hemi-Parkinson's disease, in whom basal ganglia impairment is most pronounced in one hemisphere. The CNV, recorded from 21 scalp positions in a Go/NoGo task, was maximal over central medial regions in control subjects. For hemi-Parkinson's disease subjects, activity was shifted more frontally, reduced in the midline and lateralised towards the side of greatest basal ganglia impairment. With 143 channel whole-scalp magneto encephalography (MEG) we are further examining asymmetries in supplementary motor/premotor cortical activity prior to self-paced voluntary movement. In preliminary results, one hemi-Parkinson's disease patient with predominantly left-side symptoms showed strong medial activity consistent with a dominant source in the left supplementary motor area (SMA). Three patients showed little medial activity, but early bilateral sources within lateral premotor cortex. Results suggest greater involvement of lateral premotor rather than the SMA prior to movement in Parkinson's disease and provide evidence for asymmetric function of the SMA in hemi- Parkinson's disease, with reduced activity on the side of greatest basal ganglia deficit.

Recruitment of single human low-threshold motor units with increasing loads at different muscle lengths

We investigated the recruitment behaviour of low threshold motor units in flexor digitorum superficialis by altering two biomechanical constraints: the load against which the muscle worked and the initial muscle length. The load was increased using isotonic (low load), loaded dynamic (intermediate load) and isometric (high load) contractions in two studies. The initial muscle position reflected resting muscle length in series A, and a longer length with digit III fully extended in series B. Intramuscular EMG was recorded from 48 single motor units in 10 experiments on five healthy subjects, 21 units in series A and,27 in series B, while subjects performed ramp up, hold and ramp down contractions. Increasing the load on the muscle decreased the force, displacement and firing rate of single motor units at recruitment at shorter muscle lengths (P < 0.001, dependent t-test). At longer muscle lengths this recruitment pattern was observed between loaded dynamic and isotonic contractions, but not between isometric and loaded dynamic contractions. Thus, the recruitment properties of single motor units in human flexor digitorum superficialis are sensitive to changes in both imposed external loads and the initial length of the muscle. (C) 2003 Elsevier Ltd. All rights reserved.

Risk Categories Disclosed in the Administration Reports of Brazilian Companies with ADRs

The study aims to find the categories of risks disclosed in the Administration Reports of Brazilian companies with the issuance of ADR`s. The research is characterized as descriptive, accomplished through doucmentary analysis. The sample includes 28 Brazilian companies with the issuance of American Depository Receipt (ADR`s) in the Stock Exchange of New York (USA). We have tried to identify the categories of risk, presented by the companies surveyed in the Administration Reports (AR) of 2007. Seven categories of corporate risks were considered, identified through COSO (2004) methodology strategic risks, operational risks, legal risks and image risks,. The survey results show that in general there is no standaardization of the types sof risks disclosed by the companies. A total of 14 types of risks havd been identified. The predominant category in the disclosure was the operational risk, with 20.72% of the observations. There was no disclosre of image risk in the AR of the companies surveyed. It was found that 19 companies, 67.86% of the surveyed companies, demonstrate some kind of risk to which they are exposed. On the other hand, nine companies (32.14%) did not show any kind of risk.

Depression in women living with HIV: clinical and psychosocial correlates

The number of Brazilian women living with HIV has increased significantly in past years, rendering studies of their particular care demands including psychiatric issues. This study measures the prevalence of major depression, using the Structured Clinical Interview for DSM-IV Axis I Disorders, in a sample of 120 women living with HIV in treatment at a reference centre in So Paulo. Socio-demographic variables, HIV-related clinical and laboratory data, including CD4+ cell counts and HIV plasma viral loads, as well as psychosocial features (intimate relationships, disclosure of HIV serostatus, partner`s serostatus and patient`s emotional and financial support) were investigated as factors potentially associated with depression. The prevalence of major depression at the time of evaluation was 25.8% (95% CI 18.2-33.4%). Clinical status (p = 0.002), lack of emotional support (p = 0.02), use of antidepressants (p = 0.028) and length of time since HIV diagnosis (p = 0.05) were associated with major depression in univariate analysis. In multivariate multiple-regression model, HIV clinical status, lack of emotional support and higher plasma viral loads were associated with depression. Sixty per cent of the women have a major depression diagnosis during lifetime. We conclude that major depression is highly prevalent among women living with HIV, but it is still underdiagnosed and undertreated.

ACHIEVEMENTS AND CHALLENGES OF ISPRM

This paper describes the history of the International Society of Physical and Rehabilitation Medicine (ISPRM) Past achievements. and current challenges are outlined ISPRM has been successful In setting up a central office. attracting individual and national members,. holding International congresses, and establishing relations with the Journal of Rehabilitation Medicine (JRM) as the organization`s official journal ISPRM is currently; In official relations with the World Health Organization (WHO) and collaborates closely, with WHO`s Disability and Rehabilitation team ISPRM, however also faces challenges with regard to its growth and the realization of its goals These Include boundaries of voluntary leadership. limited economic resources, the need for enhancing the central office. variations in membership. limits of the current congress bidding system and structure, relations with regional societies, and the need to further develop policies within the field of Physical and Rehabilitation Medicine (PRM) and In relation to WHO and the United Nations system is concluded that ISPRM must evolve from an organization, of which the main activities ay-e to hold a biennial congress hosted by a member nation and to provide input to WHO on request. Into a professional non-governmental organization (NGO) ISPRA should embark on assuming, a leadership role at the further development of PRM within the broader area of human functioning and rehabilitation

ISPRM`S WAY FORWARD

This paper outlines approaches to developing the International Society of Physical and Rehabilitation Medicine (ISPRM) and addresses many current challenges Most importantly, these approaches provide the basis for ISPRM to develop its leadership role within the field of Physical and Rehabilitation Medicine (PRM) and in relation to the World Health Organization (WHO) and the United Nations (UN) system at large. They also address a number of specific critiques of the current situation. A positioning of ISPRM within the world architecture of the UN and WHO systems, as well as the consideration and fostering of respective emerging regional PRM societies, is central to establishing networking connections at different levels of the world society. Yearly congresses, possibly in co-operation with a regional society, based on a defined regional rotation, are suggested. Thus, frustration with the current bidding system for a biennial congress and an intermediate meeting could be overcome. Yearly congresses are also an important step towards increasing the organization`s funding base, and hence the possibility to expand the functions of ISPRM`s central office. ISPRM`s envisioned leadership role in the context of an international web of PRM journals complementing the formally defined official journal of ISPRM, regional societies and so forth, is an inclusive rather than exclusive approach that contributes to the development of PRM journals worldwide. An important prerequisite for the further development of ISPRM is the expansion and bureaucratization of its Central Office, adding professionalism and systematic allocation of resources to the strengths of the voluntary engagement of individual PRM doctors.

Premovement activity of the pre-supplementary motor area and the readiness for action: Studies of time-resolved event-related functional MRI

The supplementary motor area (SMA) is thought to play in important role in the preparation and organisation of voluntary movement. It has long been known that cortical activity begins to increase up to 2 s prior to voluntary self-initiated movement. This increasing premovement activity measured in EEG is known as the Bereitschaftspotential or readiness potential. Modern functional brain imaging methods, using event-related and time-resolved functional MRI techniques, are beginning to reveal the role of the SMA, and in particular the more anterior pre-SMA, in premovement activity associated with the readiness for action. In this paper we review recent studies using event-related time-resolved fMRI methods to examine the time-course of activation changes within the SMA throughout the preparation, readiness and execution of action. These studies suggest that the preSMA plays a common role in encoding or representing actions prior to our own voluntary self-initiated movements, during motor imagery, and from the observation of others' actions. We suggest that the pre-SMA generates and encodes motor representations which are then maintained in readiness for action. (c) 2005 Elsevier B.V. All rights reserved.

The selection of intended actions and the observation of others' actions: A time-resolved fMRI study

Whenever we plan, imagine, or observe an action, the motor systems that would be involved in preparing and executing that action are similarly engaged. The way in which such common motor activation is formed, however, is likely to differ depending on whether it arises from our own intentional selection of action or from the observation of another's action. In this study, we use time-resolved event-related functional MRI to tease apart neural processes specifically related to the processing of observed actions, the selection of our own intended actions, the preparation for movement, and motor response execution. Participants observed a finger gesture movement or a cue indicating they should select their own finger gesture to perform, followed by a 5-s delay period; participants then performed the observed or self-selected action. During the preparation and readiness for action, prior to initiation, we found activation in a common network of higher motor areas, including dorsal and ventral premotor areas and the pre-supplementary motor area (pre-SMA); the more caudal SMA showed greater activation during movement execution. Importantly, the route to this common motor activation differed depending on whether participants freely selected the actions to perform or whether they observed the actions performed by another person. Observation of action specifically involved activation of inferior and superior parietal regions, reflecting involvement of the dorsal visual pathway in visuomotor processing required for planning the action. In contrast, the selection of action specifically involved the dorsal lateral prefrontal and anterior cingulate cortex, reflecting the role of these prefrontal areas in attentional selection and guiding the selection of responses. (c) 2005 Elsevier Inc. All rights reserved.

Lateralized deficit of response inhibition in early-onset schizophrenia

Background. The ability to inhibit inappropriate or unwanted actions is a key element of executive control. The existence OF executive function deficits in schizophrenia is consistent with frontal lobe theories of the disorder. Relatively few Studies have examined response inhibition in schizophrenia, and none in adolescent patients with early-onset schizophrenia (EOS). Methods. Twenty-one adolescents with (lie onset of clinically impairing psychosis before 19 years of age and 16 matched controls performed a stop-signal task to assess response inhibition. The patients with EOS were categorized Lis paranoid (n= 10) and Undifferentiated subtypes (n= 11). The undifferentiated group had higher levels of negative symptomatology. Stop-signal reaction time (SSRT) and go-signal reaction time (Go-RT) were analysed with respect to hand of response. Results. The Undifferentiated early-onset patients had significantly longer SSRTs, indicative of poor response inhibition, for the left hand compared to the paranoid early-onset patients and control participants. No differences existed for inhibitory control with the right hand. The three groups did not differ in Go-RT. Conclusions. Our results indicate a specific lateralized impairment of response inhibition in patients With Undifferentiated, but not paranoid, EOS. These findings are consistent with reports of immature frontostriatal networks in EOS and implicate areas such as the pre-motor cortex and Supplementary motor area (SMA) that are thought to play a role in both voluntary initiation and inhibition of movement.