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PubMed2006

Bone density spatial patterns in the distal radius reflect habitual hand postures adopted by quadrupedal primates.

Primates adopt diverse hand postures during terrestrial and above-branch quadrupedal locomotion--knuckle-walking, digitigrady, and palmigrady--that incorporate varying degrees of wrist dorsiflexion (i.e., extension). Although relationships between hand postures, wrist joint range of motion, and the external properties of wrist bones (e.g., surface morphology) have been examined, the relationship between hand postures and the internal properties of wrist bones (e.g., bone density) remains largely unexplored. Because articular joint surfaces transmit mechanical loads between conjoining limb bones, measures of density (e.g., magnitudes and patterns) in the subchondral cortical plate of bone of the distal radius can be used to evaluate load regimes experienced by the wrist joint in different hand postures. We assessed apparent (i.e. optical) density patterns in several extant catarrhine primate taxa partitioned into different hand posture groups: knuckle-walking apes, digitigrade monkeys, and palmigrade monkeys. Computed tomography osteoabsorptiometry (CT-OAM) was used to construct maximum intensity projection (MIP) maps of apparent densities. High apparent density areas were characterized relative to a dorsal-volar reference plane and compared across hand posture groups. All groups had large percentage areas of high apparent density in the dorsal region of the distal radial articular surface. Only knuckle-walking apes, however, had a large percentage area of high apparent density in the volar region of the distal radial articular surface. These patterns are consistent with radiocarpal articulations in specific hand postures as evidenced by available radiographic data and suggest that the different habitual hand postures adopted by monkeys and African apes during quadrupedal locomotion have different stereotypic loading patterns. This has implications for understanding the functional morphology and evolution of knuckle-walking and digitigrade hand postures in primates.

Animals↗
PubMed2006

Functional connectivity between cortical hand motor and language areas during recovery from aphasia.

Previous data indicate that in healthy subjects, there is a connectivity between cortical areas for hand movement and language on the left hemisphere. This link is possibly mediated by the so-called mirror neuron system. The present study investigated the functional relationship between linguistic and hand movement processing in patients who were recovering from post-stroke aphasia. The excitability of the right- and left-hand motor cortex during language production in patients who were recovering from post-stroke aphasia and age-matched controls was investigated. As control, phonation was investigated. Hand motor cortex excitability was assessed with Motor Evoked Potentials which were elicited by Transcranial Magnetic Stimulation (TMS). In patients, reading aloud enhanced the excitability of the right hemispheric hand motor cortex, whereas phonation had no effect on hand motor cortex excitability. In the control group, an increased excitability of the left hemispheric hand motor system was found during reading aloud in accordance with previous data. The present data suggest a functional connectivity between regions mediating hand movements and reading. This may indicate that the right hemisphere participates in language processing as far as involved in single word reading in patients recovering from aphasia. The coactivation between cerebral representations of hand movements and language may be used therapeutically for aphasia rehabilitation.

Adult↗
PubMed2006

Correlations between bone mineral density of the hand and other skeletal sites as measured by DXA in Chinese women and men.

This study was aimed at assessing the correlations between the bone mineral density (BMD) of the hand and other skeletal sites in Chinese women and men. We measured the BMD of the total body, the anteroposterior lumbar spine (L2-L4), bilateral proximal femurs (i.e., total hip, femoral neck, and trochanter), and bilateral total hands in 363 Chinese adults (96 males, 267 females) using dual-energy X-ray absorptiometry (DXA). Data were analyzed by descriptive statistics, Student's t tests, and Pearson's correlation coefficients (r). We found that bilateral hand measurements reduced precision error by 36% as compared with a single hand measurement. Dominant hand BMD was significantly higher than nondominant hand BMD. For both the dominant and nondominant sides, hand BMD was significantly higher in males than in females. Hand BMD correlated significantly (p<0.001) with the BMD of all skeletal sites for all subjects (r=0.681-0.848), the male group (r=0.568-0.857), and the female group (r=0.687-0.859). After normal references for the Chinese population have been established, further investigations may determine the clinical usefulness of hand BMD measurement in the diagnosis of osteoporosis and the prediction of fracture risk.

Absorptiometry, Photon↗
PubMed2005

The association between lead contamination on the hand and blood lead concentration: a workplace application of the sodium sulphide (Na2S) test.

OBJECTIVES: Lead is one of the major causes of workplace poisoning and lead contamination on skin is a possible route of lead absorption. Using a colourimetric method with sodium sulphide (Na2S), we examined whether the lead on skin represents longer-term lead exposure. METHODS: This cross-sectional study of 119 lead-handling workers in a battery recycling plant in Japan was conducted in July 2004. The main outcome measure was skin-colour darkening on the workers' hands, visualised by wetting the seemingly clean hands of the workers with 1% Na2S solution (128 mmol/L): the Na2S test. This study then examined the relationships between the Na2S test results and workers' blood lead concentration (BLC) and hygiene activities. RESULTS: The Na2S test produced skin-colour darkening of the hands of 92 (77%) of the lead workers, although 88 of them had washed their hands with soap and 50 had bathed before taking the test. In the bivariate analyses, a positive result in the Na2S test was associated with not washing hands (p=0.009), not bathing (p=0.061), and a higher BLC (p=0.008). The association between the results of the Na2S test and BLC was still significant in the multivariate linear regression analysis adjusted for age and hand washing (p<0.001). CONCLUSIONS: Lead contamination on workers' hands, otherwise unapparent, was clearly demonstrated by the Na2S test. The result of this test was associated with BLC in addition to the hygiene activities after the last work with lead. As the lead contamination on the hand is persistent, simply encouraging hand washing may not be sufficient to reduce lead intake into body.

Cross-Sectional Studies↗
PubMed1995

Hand motor performance and degree of asymmetry in monozygotic twins.

To determine whether the absolute degree of asymmetry of hand motor performance (irrespective of direction of this asymmetry) may have a heritable component we examined 20 pairs of monozygotic (MZ) twins of whom 10 pairs were concordantly right-handed (MZ-RR) and 10 pairs discordant for handedness (MZ-RL). The tests comprised measurements of the maximum left and right hand tapping rate as well as a paper-and-pencil test of left and right hand motor proficiency. Intraclass correlations within MZ-RR and MZ-RL for absolute degree of hand motor asymmetry were not significant. In contrast, significant intrapair correlations emerged for overall hand motor performance, a measure unrelated to laterality. These results demonstrate that at least in MZ twins the degree of hand motor asymmetry is mainly determined by non-genetic factors, whereas overall hand motor skill is more likely to be influenced by the genome. In addition, the lack of a difference in overall hand motor performance between MZ twins and 40 singletons studied as controls would not support hypotheses explaining behavioural asymmetry in twins, or their discordance for asymmetry, by developmental dysfunction.

Adult↗
PubMed2001

Hand-centered attentional and motor asymmetries in unilateral neglect.

On several accounts of "selection for action", acting on a target object among distractors requires that irrelevant inputs and responses to these inputs are inhibited, and relevant inputs and responses selected. In unilateral neglect associated with right-hemisphere lesions, selection processes may be biased toward stimuli on the right, as right is usually defined by head and body hemispace. In normal subjects performing reaching-to-target tasks, selection may be "hand-centered" (Tipper S., Lortie C., Baylis G.C., Journal of Experimental Psychology: Human Perception and Performance 18(4) (1992) 891-905) in that distractor stimuli close to the hand compete strongly with the target for the control of action, causing greater interference than distractors far from the hand. We reasoned that in the context of a reaching task, a left-right asymmetry in unilateral neglect may be defined with respect to the position of the hand. This predicts that target and distractor stimuli to the left of hand (i.e. requiring leftward movements for contact) should compete less strongly for the control of action than stimuli to the right of the hand. We tested this hypothesis by asking eight patients with unilateral neglect (and 12 healthy controls) to reach to central targets presented alone and with surrounding distractors from left or right start positions. Patients with neglect, but not controls, were slower to initiate reaches from right start as compared to left start positions. In this context, patients showed interference from distractors to the right of the hand and facilitation from distractors to the left of the hand. This indicates that a left-right selection asymmetry in neglect may be hand-centered. These data can be explained on a model of damage to the portion of a distributed neuronal population coding movement vectors to stimuli in relatively leftward locations.

Adult↗
PubMed2000

Effectiveness of a hospital-wide programme to improve compliance with hand hygiene. Infection Control Programme.

BACKGROUND: Hand hygiene prevents cross infection in hospitals, but compliance with recommended instructions is commonly poor. We attempted to promote hand hygiene by implementing a hospital-wide programme, with special emphasis on bedside, alcohol-based hand disinfection. We measured nosocomial infections in parallel. METHODS: We monitored the overall compliance with hand hygiene during routine patient care in a teaching hospital in Geneva, Switzerland, before and during implementation of a hand-hygiene campaign. Seven hospital-wide observational surveys were done twice yearly from December, 1994, to December, 1997. Secondary outcome measures were nosocomial infection rates, attack rates of methicillin-resistant Staphylococcus aureus (MRSA), and consumption of handrub disinfectant. FINDINGS: We observed more than 20,000 opportunities for hand hygiene. Compliance improved progressively from 48% in 1994, to 66% in 1997 (p<0.001). Although recourse to handwashing with soap and water remained stable, frequency of hand disinfection substantially increased during the study period (p<0.001). This result was unchanged after adjustment for known risk factors of poor adherence. Hand hygiene improved significantly among nurses and nursing assistants, but remained poor among doctors. During the same period, overall nosocomial infection decreased (prevalence of 16.9% in 1994 to 9.9% in 1998; p=0.04), MRSA transmission rates decreased (2.16 to 0.93 episodes per 10,000 patient-days; p<0.001), and the consumption of alcohol-based handrub solution increased from 3.5 to 15.4 L per 1000 patient-days between 1993 and 1998 (p<0.001). INTERPRETATION: The campaign produced a sustained improvement in compliance with hand hygiene, coinciding with a reduction of nosocomial infections and MRSA transmission. The promotion of bedside, antiseptic handrubs largely contributed to the increase in compliance.

Anti-Infective Agents, Local↗
PubMed1993

Hand injuries in children presenting to a pediatric emergency department.

STUDY OBJECTIVE: To study the epidemiology of pediatric hand injuries. DESIGN: Retrospective chart review. SETTING: Emergency department of a children's hospital. PARTICIPANTS: All patients with a final diagnosis of hand injury from July through December 1989. INTERVENTIONS: None. RESULTS: Four hundred sixty-four patients (287 boys and 177 girls; median age, 10 years) with a total of 477 hand injuries were enrolled in the study. The most common types of injuries were lacerations (38.1%), soft tissue injuries (28.7%), and fractures (19.3%) and sprains (8%); most (60.8%) were sustained at home. Children with lacerations and burns were significantly younger than those with other types of hand injuries (P < .0001). Children with fractures, sprains, and sports injuries were significantly older than those with other types of hand injuries (P < .001). The fifth finger was the most commonly fractured digit (37%), and the fifth metacarpal was the most commonly fractured bone (P < .01). Boys were more likely than girls to sustain sports-related injuries (P < .05) and hand injuries resulting from first fights (P < .01). More hand injuries were associated with football than with any other organized sport (P < .01). All but 16 children (3.4%) were managed as outpatients. CONCLUSION: Hand trauma accounts for a significant number of pediatric ED visits. Physicians caring for children in the ED setting must be prepared to manage a wide spectrum of pediatric hand injuries.

Adolescent↗
PubMed2002

Confusing the mind by crossing the hands.

Observers made temporal order judgements (TOJs) regarding which of two tactile stimuli presented to either hand (at stimulus onset asynchronies of up to 200 ms) occurred first. When the observers' hands were placed in an uncrossed posture (i.e., each hand in its own hemispace), performance was accurate, with a just noticeable difference (JND; the smallest interval which produces 75% correct performance) of 34 ms. By contrast, when the hands were crossed over the midline, performance declined such that 124 ms was needed for accurate performance. In a second experiment, we presented visual instead of tactile stimuli to evaluate the relative contribution of motor and perceptual confusions to the effect. While performance with crossed hands was significantly worse than with uncrossed hands (JND=36 vs. 31 ms, respectively), this difference was negligible compared to that with tactile stimuli. In a third experiment, experienced observers showed a robust crossed-hands deficit which was not improved by using different fingers on either hand. We argue that the decline in tactile discrimination performance when the hands are crossed reflects a failure to represent appropriately near simultaneous bimanual tactile stimuli, and stands in marked contrast to many recent observations of efficient remapping of singly-presented tactile stimuli.

Analysis of Variance↗
PubMed1999

Localization of the motor hand area using transcranial magnetic stimulation and functional magnetic resonance imaging.

OBJECTIVE: The anatomical location of the motor area of the hand may be revealed using functional magnetic resonance imaging (fMRI). The motor cortex representation of the intrinsic hand muscles consists of a knob-like structure. This is omega- or epsilon-shaped in the axial plane and hook-shaped in the sagittal plane. As this knob lies on the surface of the brain, it can be stimulated non-invasively by transcranial magnetic stimulation (TMS). It was the aim of our study to identify the hand knob using fMRI and to reveal if the anatomical hand knob corresponds to the hand area of the motor cortex, as identified by TMS, by means of a frameless MRI-based neuronavigation system. METHODS: Suprathreshold transcranial magnetic stimuli were applied over a grid on the left side of the scalp of 4 healthy volunteers. The motor evoked potentials (MEPs) were recorded from the contralateral small hand muscles, and the centers of gravity (CoG) of the MEPs were calculated. The exact anatomical localization of each point on the grid was determined using a frameless MRI-based neuronavigation system. In each subject, the hand area of the motor cortex was visualized using fMRI during sensorimotor activation achieved by clenching the right hand. RESULTS: In all 4 subjects, the activated precentral site in the fMRI and the CoG of the MEP of all investigated muscles lay within the predicted anatomical area, the so-called hand knob. This knob had the form of an omega in two subjects and an epsilon in the other two subjects. CONCLUSIONS: TMS is a reliable method for mapping the motor cortex. The CoG calculated from the motor output maps may be used as an accurate estimation of the location of the represented muscle in the motor cortex.

Adult↗
PubMed2001

Microbiologic effectiveness of hand washing with soap in an urban squatter settlement, Karachi, Pakistan.

We conducted a study in a squatter settlement in Karachi, Pakistan where residents report commonly washing their hands to determine if providing soap, encouraging hand washing, and improving wash-water quality would improve hand cleanliness. We allocated interventions to 75 mothers and collected hand-rinse samples on unannounced visits. In the final model compared with mothers who received no hand-washing intervention, mothers who received soap would be expected to have 65% fewer thermotolerant coliform bacteria on their hands (95% CI 40%, 79%) and mothers who received soap, a safe water storage vessel, hypochlorite for water treatment, and instructions to wash their hands with soap and chlorinated water would be expected to have 74% fewer (95% CI 57%, 84%). The difference between those who received soap alone, and those who received soap plus the safe water vessel was not significant (P = 0.26). Providing soap and promoting hand washing measurably improved mothers' hand cleanliness even when used with contaminated water.

Female↗
PubMed2001

Reaching-lifting-placing task during standing after stroke: Coordination among ground forces, ankle muscle activity, and hand movement.

OBJECTIVE: To investigate the coordination among hand movement, ground forces, and muscle activity in standing stroke patients reaching forward and lifting an object from a table. DESIGN: Survey. SETTING: Research laboratory. PATIENTS: Eight stroke patients and 8 persons serving as controls. MAIN OUTCOME MEASURE: Symmetry of percentage of body weight (BW) during initial standing, velocity and hand path trajectory, ankle muscle electromyography. Temporal and spatial parameters in percentage of movement time were recorded by using 2 forceplates, 3-dimensional kinematics, and surface electromyography. Motor function, sensory function, and functional performance were also assessed. RESULTS: Weight distribution during initial standing was significantly higher (57.4% +/- 8.1% BW) on the nonparetic leg. All subjects had preserved the preparatory loading phase, and after onset of hand movement loading shifted to the contralateral leg. Ankle muscle activity onset (lateral gastrocnemius [LG]) occurred after loading. In stroke subjects, LG was consistently activated first in the nonparetic leg, regardless of which arm performed the task. During paretic hand task, the reaching phase was significantly longer and the lifting phase significantly shorter compared with that of the nonparetic hand task and with that of the controls. In the paretic task, the hand path velocity was not bell-shaped; the object lifting was. CONCLUSIONS: Stroke subjects preserve the coordination between ground forces and hand movement. The lack of spontaneous use of the paretic hand is primarily caused by difficulties of planning the hand trajectory in space, as reflected by temporal and spatial parameters during task performance.

Activities of Daily Living↗
PubMed2006

[Optimizing surgical hand disinfection].

For more than 110 years hands of surgeons have been treated before a surgical procedure in order to reduce the bacterial density. The kind and duration of treatment, however, has changed significantly over time. Recent scientific evidence suggests a few changes with the aim to optimize both the efficacy and the dermal tolerance. Aim of this article is the presentation and discussion of new insights in surgical hand disinfection. A hand wash should be performed before the first disinfection of a day, ideally at least 10 min before the beginning of the disinfection as it has been shown that a 1 min hand wash significantly increases skin hydration for up to 10 min. The application time may be as short as 1.5 min depending on the type of hand rub. Hands and forearms should be kept wet with the hand rub for the recommended application time in any case. A specific rub-in procedure according to EN 12791 has been found to be suitable in order to avoid untreated skin areas. The alcohol-based hand rub should have a proven excellent dermal tolerance in order to ensure appropriate compliance. Considering these elements in clinical practice can have a significant impact to optimize the high quality of surgical hand disinfection for prevention of surgical site infections.

Disinfectants↗
PubMed2003

Use of alcohol hand sanitizer as an infection control strategy in an acute care facility.

BACKGROUND: Nosocomial infections are a major problem in health care facilities, resulting in extended durations of care, substantial morbidity and mortality, and excess costs. Since alcohol gel hand sanitizers combine high immediate antimicrobial efficacy with ease of use, this study was carried out to determine the effect of the use of an alcohol gel hand sanitizer by caregivers on infection types and rates in an acute care facility. Patients were educated about the study through a poster on the unit, and teachable patients were given portable bottles of the alcohol hand gel for bedside use, along with an educational brochure explaining how and why to practice good hand hygiene. METHODS: Infection rate and type data were collected in 1 unit of a 498-bed acute care facility for 16 months (February 2000 to May 2001). An alcohol gel hand sanitizer was provided and used by caregivers in the orthopedic surgical unit of the facility during this period. RESULTS: The primary infection types (more than 80%) found were urinary tract (UTI) and surgical site (SSI) infections. Infection types and rates for the unit during the period the alcohol hand sanitizer (intervention) was used were compared with the infection types and rates for the same unit when the alcohol hand sanitizer was not used (baseline); the results demonstrated a 36.1% decrease in infection rates for the 10-month period that the hand sanitizer was used. CONCLUSION: This study indicates that use of an alcohol gel hand sanitizer can decrease infection rates and provide an additional tool for an effective infection control program in acute care facilities.

Analysis of Variance↗
PubMed2003

Rates of hand disinfection associated with glove use, patient isolation, and changes between exposure to various body sites.

BACKGROUND: Handwashing is the most effective and economic intervention shown to reduce nosocomial infection rates. However, studies have consistently documented low hand disinfection compliance. Literature regarding the roles that concomitant glove use and isolation precautions play in health care worker compliance with hand disinfection is limited. It is unclear whether workers change gloves and disinfect hands adequately between exposures to different body sites/secretions while caring for a patient. METHODS: This was an observational study in which hand disinfection compliance and glove use among workers was evaluated in 2 intensive care units at a tertiary care hospital. RESULTS: Five hundred eighty-nine opportunities for hand disinfection were recorded in 40 hours of observation. Overall compliance was 22.1%. We found a statistically significant, positive association between glove use and subsequent hand disinfection (relative risk [RR], 3.9 [95% CI, 2.5-6.0]; P <.0001). Isolation precautions did not significantly increase disinfection compliance. Only 4.8% (3/63) of workers appropriately complied with disinfection when hands were exposed to multiple body sites/secretions while caring for a patient. CONCLUSIONS: Glove use increases compliance with hand disinfection. Isolation precautions do not increase compliance. Workers do not appropriately comply with disinfection guidelines when attending to multiple body sites/secretions on the same patient. Compliance with hand disinfection remains low.

Attitude of Health Personnel↗
PubMed2000

Effects of preferred hand and sex on the perception of tactile simultaneity.

The effects of handedness, sex and the influence of hand placement in extrapersonal space on temporal information processing was investigated by measuring thresholds for perceiving the simultaneity of pairs of tactile stimuli. Simultaneity thresholds of preferred right handed and left handed university students with left hemisphere speech representation were compared using unimanual and bimanual stimulation at three hand placements (midline, lateral and crossed). In unimanual conditions two fingers of one hand were stimulated (single hemisphere), whereas in the bimanual conditions one finger of each hand was stimulated (cross hemispheres). Bimanual minus unimanual thresholds provided an estimate of interhemisphere transmission time (IHTT) regardless of hand placement. The effects of hemispace varied with the type of stimulation. With unimanual stimulation, overall thresholds were longer at the midline placement, however, with bimanual stimulation, thresholds were longer when the hands were spatially separated (crossed and/or uncrossed). Left handers' IHTTs were 8 ms faster than those of right handers. IHTTs in males were faster than females with hands placed in lateral (by 10.8 ms) or crossed (by 9.8 ms) but not midline positions. It was concluded that the cerebral hemispheres are equally capable of discriminating temporal intervals, but that the left hemisphere predominates when there is uncertainty about location of stimulation.

Adolescent↗
PubMed2005

Attitudes and perceptions toward hand hygiene among healthcare workers caring for critically ill neonates.

BACKGROUND: Infectious complications are frequent among critically ill neonates. Hand hygiene is the leading measure to prevent healthcare-associated infections, but poor compliance has been repeatedly documented, including in the neonatal setting. Hand hygiene promotion requires a complex approach that should consider personal factors affecting healthcare workers' attitudes. OBJECTIVE: To identify beliefs and perceptions associated with intention to comply with hand hygiene among neonatal healthcare workers. METHODS: An anonymous, self-administered questionnaire (74 items) based on the theory of planned behavior was distributed to 80 neonatal healthcare workers to assess intention to comply, attitude toward hand hygiene, behavioral and subjective norm perceptions, and perception of difficulty to comply. Variables were assessed using multi-item measures and answers to 7-point bipolar scales. All multi-item scales had satisfactory internal consistency (alpha > 0.7). Multivariate logistic regression identified independent perceptions or beliefs associated with a positive intention to comply. RESULTS: The response rate was 76% (61 of 80). Of the 49 nurses and 12 physicians responding, 75% believed that they could improve their compliance with hand hygiene. Intention to comply was associated with perceived control over the difficulty to perform hand hygiene (OR, 3.12; CI95, 1.12 to 8.70; P = .030) and a positive perception of how superiors valued hand hygiene (OR, 2.89; CI95, 1.08 to 7.77; P = .035). CONCLUSION: Our data highlight the importance of the opinions of superiors and a strong perceived controllability over the difficulty to perform hand hygiene as possible internal factors that may influence hand hygiene compliance.

Adult↗
PubMed2002

Functional brain reorganization for hand movement in patients with multiple sclerosis: defining distinct effects of injury and disability.

Previous work has demonstrated potentially adaptive cortical plasticity that increases with brain injury in patients with multiple sclerosis. However, animal studies showing use-dependent changes in motor cortex organization suggest that functional changes also may occur in response to disability. We therefore wished to test whether brain injury and disability lead to distinguishable patterns of activation with hand movement in patients with multiple sclerosis. By employing a passive as well as an active movement task, we also wished to test whether these changes were independent of voluntary recruitment and thus more likely to reflect true functional reorganization. Fourteen patients [Extended Disability Status Score (EDSS) 0-7.5] with relapsing-remitting multiple sclerosis were selected on the basis of pathology load and hand functional impairment for three study groups: group 1, low diffuse central brain injury (DCBI) as assessed from relative N-acetylaspartate concentration (a marker of axonal integrity) and normal hand function (n = 6); group 2, greater DCBI and normal hand function (n = 4); and group 3, greater DCBI and impaired hand function (n = 4). Functional MRI (fMRI) was used to map brain activation with a four-finger and both one-finger passive and active flexion-extension movement tasks for the three groups. Considering all the patients, we found increased activity in ipsilateral premotor and ipsilateral motor cortex (IMC) and in the ipsilateral inferior parietal lobule with increasing global disability (as assessed from the EDSS score). These changes appear to define true functional reorganization, as fMRI activations in IMC (r = 0.87, P < 0.001) and in the contralateral motor cortex (r = 0.67, P < 0.007) were highly correlated between active and passive single finger movements. We attempted to disambiguate any distinct effects of disability and brain injury by direct contrasts between patients differing predominantly in one or the other. To make these contrasts as powerful as possible, we used impairment of finger tapping as a measure of disability specific to the hand tested. A direct contrast of patients matched for DCBI, but differing in hand disability (group 3 - group 2) showed greater bilateral primary and secondary somatosensory cortex activation with greater disability alone. A contrast matched for hand disability, but differing in DCBI (group 2 - group 1) showed a different pattern of changes with relative ipsilateral premotor cortex and bilateral supplementary motor area activity. We conclude that the pattern of brain activity with finger movements changes both with increasing DCBI and with hand disability in patients with multiple sclerosis, and that these changes are distinct. Those related directly to disability may reflect responses to altered patterns of use. As injury- and disability-related activation changes are found even with passive finger movements, they may reflect true brain reorganization.

Analysis of Variance↗