Reliability of speed of contraction and endurance dynamometric measurements of the pelvic floor musculature in stress incontinent parous women.

AIMS: To evaluate the test-retest reliability of dynamometric measurements of the pelvic floor muscles (PFM) during speed and endurance tests. METHODS: Nineteen parous women suffering from stress urinary incontinence (SUI) participated in the study. Two PFM evaluation sessions were conducted using the dynamometric speculum. For the speed test, the women were instructed to contract maximally and relax as quickly as possible during a 15-s test period. The speed of contraction was quantified by the rate of force development of the first contraction and the number of contractions performed. The maximal strength value attained during the speed test was also extracted from the curves. For the endurance test, the subjects were asked to maintain a maximal contraction for 90 s. The normalized area under the force curve was utilized as the endurance parameter. The reliability of the data was evaluated using the generalizability theory. Two reliability estimates were calculated, the dependability indices (Phi) and the standard error of measurement (SEM), for one measurement session involving one trial. RESULTS: The indices of dependability obtained indicate that the reliability of the speed of contraction and endurance parameters are good (Phi=0.79-0.92). The corresponding SEMs were 1.39 N/s, 1 contraction, 1.00 N, and 298%*s for the rate of force development, number of contractions, maximal strength and normalized area, respectively. CONCLUSION: This study indicates that the speed of contraction and endurance parameters possess good test-retest reliability. The inclusion of these parameters in the PFM assessment is therefore highly recommended for assessing changes in PFM in incontinent women.

Interlimb transfer of grasp orientation is asymmetrical.

One the most fundamental aspects of the human motor system is the hemispheric asymmetry seen in behavioral specialization. Hemispheric dominance can be inferred by a contralateral hand preference in grasping. Few studies have considered grasp orientation in the context of manual lateralization and none has looked at grasp orientation with natural prehension. Thirty right-handed adults performed precision grasps of a cylinder using the thumb and index fingers, and the opposition axis (OA) was defined as the line connecting these two contact points on the cylinder. Subjects made ten consecutive grasps with one hand (primary hand movements) followed by ten grasps with the other hand (trailing movements). Differences between primary and trailing grasps revealed that each hemisphere is capable of programming the orientation of the OA and that primary movements with the right hand significantly influenced OA orientation of the trailing left hand. These results extend the hemispheric dominance of the left hemisphere to the final positions of fingers during prehension.

Comparison of strength measurements under single-joint and multi-joint conditions in hemiparetic individuals.

OBJECTIVE: It has been suggested that the measurement of strength is inappropriate in patients with stroke, in large part because of the presence of abnormal synergy patterns. The aim of the present study was to characterize force production during multi-joint maximal exertion involving different combinations of activation between shoulder and elbow flexors and extensors. DESIGN: Cross-sectional study. SETTING: Rehabilitation centre. SUBJECTS: A convenience sample of 16 chronic hemiparetic stroke subjects. MAIN OUTCOME MEASURES: Maximal torques in flexion and extension at the shoulder and the elbow were measured using static dynamometers (single-joint condition). In addition, the maximal forces produced at the wrist were measured in four directions in the sagittal plane requiring different torque combinations between shoulder and elbow flexors and extensors (multi-joint condition). RESULTS: No difference was found across directions for the ratios of maximal forces (paretic/nonparetic) in the multi-joint condition (p = 0.227; mean ratios (+/- SD) for each direction ranging from 0.59+/-0.23 to 0.68+/-0.27), suggesting that the ability to produce force did not change as a function of the required torque combination. In addition, relative torques (% of the maximal torque in the single-joint condition) exerted during the multi-joint exertions were similar on the paretic and the nonparetic side. CONCLUSIONS: These results do not support the assumption that force production is limited by abnormal synergy patterns between flexors and extensors at the shoulder and the elbow in hemiparetic patients.

Quantification of level of effort at the plantarflexors and hip extensors and flexor muscles in healthy subjects walking at different cadences.

The plantarflexor, hip extensor and hip flexor muscle groups contribute by their concentric action to generate most of the energy during level gait in healthy subjects. The goal of the present study was to determine, during the main energy generation phases, the relative demand of these three groups in 14 healthy subjects walking at four cadences (self-selected, 60, 80 and 120 steps/min). The muscular utilization ratio (MUR), that compares the net joint moment obtained during gait to the maximal potential moment (MPM) at each percentage of the gait cycle, was used to estimate the mechanical relative demand. The MPM values were obtained by regression equations developed from torque data measured with a Biodex dynamometric system. The results showed that the peak MURs increased with gait cadence. The peak values were not significantly different between sides for all cadences despite mean absolute lateral differences ranging from 7% to 10%. The mean peak MURs of both sides ranged from 51.3% to 62.6%, from 20.7% to 49.9% and from 14.9% to 42.5%, for the plantarflexors, hip flexors and hip extensors, respectively. Highly significant associations were found between the MURs and net moments (numerator of the MUR ratio), with Pearson coefficients (r) superior to 0.80 for all muscles groups. The association between the MURs and the maximal potential moments (denominator of MUR ratio) was lower (0.01

Pelvic floor muscle function in continent and stress urinary incontinent women using dynamometric measurements.

AIMS: To compare the pelvic floor muscle (PFM) function in continent and stress urinary incontinent women using dynamometric measurements. METHODS: Thirty continent women and 59 women suffering from stress urinary incontinence (SUI), aged between 21 and 44 and parous, participated in the study. An instrumented speculum was used to assess the static parameters of the PFM: (1) passive force at 19 and 24 mm of vaginal aperture (antero-posterior diameter), (2) maximal strength in a self-paced effort at both apertures, (3) rate of force development and number of contractions during a protocol of rapidly repeated 15-sec contractions, and lastly (4) absolute endurance recorded over a 90-sec period during a sustained maximal contraction. The parameters described in the two latter conditions were assessed at the aperture of 19 mm. Analyses of covariance were used to control the confounding variables of age and parity when comparing the PFM function in the continent and incontinent women. RESULTS: The continent women demonstrated higher passive force at both openings and a higher absolute endurance as compared to the incontinent women (P < or = 0.01). In the protocol of rapidly repeated contractions, the rate of force development and number of contractions were both lower in the incontinent subjects (P < or = 0.01). The differences between the two groups for maximal strength at the 19- and 24-mm apertures did not reach the statistically significant level. CONCLUSIONS: The PFM function is impaired in incontinent women. The assessment of PFM should not be restricted to maximal strength. Other parameters that discriminate between continent and incontinent women need to be added to the PFM assessment in both clinical and research settings.

Pelvic floor maximal strength using vaginal digital assessment compared to dynamometric measurements.

AIM: To compare vaginal digital assessment with dynamometric measurements for determining the maximal strength of the pelvic floor muscles (PFM). MATERIALS AND METHODS: Eighty-nine women aged between 21 and 44 participated in the study. An experienced physiotherapist evaluated the maximal strength of the PFM of these women using the modified Oxford grading system (six categories, range 0-5) and dynamometric measurements. The mean maximal forces obtained for all women with the instrumented speculum for each category of digital assessment were compared using ANOVAs. Spearman's rho coefficients were calculated to assess the correlation between the dynamometric and the digital assessments. RESULTS: According to their symptoms and pad test results, 30 women were continent and 59 had stress urinary incontinence (SUI). Based on dynamometric measurements, important overlaps were observed between each category of digital assessment. The ANOVAs indicated that force values differ across categories (F = 10.08; P < 0.001), although contrast analyses revealed no differences in the mean maximal forces between adjacent digital-assessment categories (1-2, 2-3, 3-4, 4-5). Mean force values differed significantly only between non-adjacent levels in digital assessment, for example, between 1 and 3; 1 and 4; 1 and 5; 2 and 4; 2 and 5 (P < 0.05). Significant correlations were found between the two measurements with coefficients of r = 0.727, r = 0.450, and r = 0.564 for continent, incontinent, and all women, respectively (P < 0.01). CONCLUSIONS: Even if the dynamometric mean forces of the PFM increased across subsequent categories of digital assessment, the force values between two adjacent categories do not differ. This limitation of digital assessment should be considered by clinicians and researchers when choosing treatment orientation and evaluating treatment outcomes.

Reliability of dynamometric measurements of the pelvic floor musculature.

AIMS: The objective of this study was to evaluate the reliability of strength and endurance dynamometric measurements of the pelvic floor musculature (PFM). MATERIALS AND METHODS: Twenty-nine female participants, primipara and multipara, aged between 27 and 42 and presenting different severity levels of stress urinary incontinence (SUI), participated in the study. They were evaluated using a new pelvic floor dynamometer, an instrumented speculum based on strain-gauged technology. Strength and endurance evaluations were repeated in three successive sessions, each followed by a 4-week period. Maximal strength values were recorded at three dynamometer openings (5 mm, 1 cm, and 1.5 cm between the two dynamometer branches). The maximal rate of force development (MRFD) and percentage of strength lost after 10 and 60 sec were computed from the endurance trial. The generalizability theory was applied to estimate the reliability of the PFM measurements. The reliability was quantified by the index of dependability and the corresponding standard error of measurement (SEM) for one and the mean of three trials performed in one session for the strength measurements and one trial completed in one session for the MRFD and endurance measurements. RESULTS: For the maximal strength measurements, the largest coefficient of dependability was obtained at the 1 cm opening, with a value of 0.88. The corresponding SEM reached 1.49 N. The reliability of the MRFD was also very good with a coefficient of 0.86 and an SEM of 0.056 N/sec. The reliability was minimally affected by the number of trials. The strength loss measurements at 10 and 60 sec were unreliable, with coefficient values of 0.38 and 0.10, respectively. CONCLUSIONS: The results of the present study indicate that the reliability of the strength parameters (maximal strength and MRTD measurements) was high enough for future investigations on pelvic floor rehabilitation programs.

Development of a dynamometer for measuring the isometric force of the pelvic floor musculature.

AIMS: The aim of this study was to design and develop a dynamometer providing a direct measurement of pelvic floor muscle (PFM) strength. MATERIALS AND METHODS: Two pairs of strain gauges were mounted on the moveable branch of a dynamometric speculum allowing measurements at different vaginal apertures. Linearity, repeatability, independence of the site of application of the resultant force to the lower branch of the speculum and hysteresis were tested by means of in vitro calibration studies. RESULTS: The linearity proved excellent over a range of 0-15 N with regression coefficients close to unity between imposed loads and voltage outputs. The slopes and intercepts of the regression lines were not significantly different between repeated sessions, indicating the high reliability of these in vitro measurements. The slopes and intercepts of the calibrations, using the same repertoire of loads imposed at three locations on the moving branch of the dynamometer, were not significantly different, confirming that the force measurement is independent of the site of the force application. Hysteresis was considered to be minimal. CONCLUSIONS: This study demonstrates that the dynamometer provides reliable measurements. The new device thus appears to have conceptual and measuring advantages over conventional methods and seems to be a very promising instrument for measuring pelvic floor strength.

Interaction between attention demanding motor and cognitive tasks and static postural stability.

BACKGROUND: Due to the often-reported decrease in postural stability in the elderly, it is important to understand factors that may contribute to reduced postural stability. It is possible that attention-demanding focal tasks performed concurrent with postural regulation influence postural stability. OBJECTIVE: This study utilized dual-task methodology to determine if motor or cognitive focal tasks interact with center of pressure (COP) excursion during static bipedal stance in healthy young and healthy elderly subjects (n = 18). METHODS: The cognitive task involved silently solving an orally-presented multi-step arithmetic problem over a 30-second period. The motor task was a 30-second bilateral static finger-thumb pinch task performed at 10% of maximal voluntary contraction with a pair of pinch-force transducers. Each focal task was performed separately, and in a condition in which both tasks were performed simultaneously. COP excursion was compared in quiet standing (no focal task) and during performance of the focal tasks with full vision and with vision occluded. RESULTS: Performance on the focal tasks was unaffected by increased postural demands during stance as compared to a seated baseline condition. This was the case for both age groups, and for the full vision and occluded vision conditions. Medio-lateral COP excursion was reduced over the quiet standing pretest condition when attentional focus was on the cognitive task, suggesting that COP was influenced centrally during cognition. In contrast, COP excursion increased over the quiet standing pretest condition when performing the motor focal task, suggesting a reduced ability to suppress sway when the motor system was concurrently occupied with a voluntary task that shared the same input-output resources. CONCLUSION: The ability to share attentional resources among focal and postural tasks was similar in healthy young and elderly subjects.

Effects of upper limb unilateral isometric efforts on postural stabilization in subjects with hemiparesis.

OBJECTIVE: To characterize postural stabilization during a progressive unilateral isometric abduction of the upper limb in a seated position in healthy subjects and subjects with hemiparesis. DESIGN: Convenience sample. SETTING: University secondary care rehabilitation center. PATIENTS: Twelve patients with hemiparesis and 12 subjects without neurologic disorder. INTERVENTIONS: Subjects were seated on a forceplate, with forearms fixed in cuffs mounted on a force transducer. Two trials per side of isometric abduction of arm were conducted. The orthogonal force and torque exerted was measured for each arm. MAIN OUTCOME MEASURES: Forces at the upper limbs and at the seat, global motor performance, spasticity of upper limb, grip force, and dexterity. RESULTS: Results of analyses of variance showed differences in the magnitude of the contralateral limb forces generated by subjects with hemiparesis and healthy subjects (p <.05). Normalized contralateral forces in the nonparetic upper limb associated with paretic isometric efforts were higher than those associated with nonparetic efforts and higher than those associated with efforts in healthy subjects. CONCLUSION: These results suggest that postural stabilization during isometric efforts is impaired in subjects with hemiparesis.

Effect of seat cushion on dynamic stability in sitting during a reaching task in wheelchair users with paraplegia.

OBJECTIVES: To examine the effects of seat cushions on dynamic stability in sitting during a controlled reaching task by wheelchair users with paraplegia. DESIGN: A randomized, controlled test. SETTING: Rehabilitation center. PARTICIPANTS: Nine wheelchair users with paraplegia. INTERVENTIONS: Three types of cushions--an air flotation, a generic contoured, and a flat polyurethane foam--were tested during a controlled reaching task in ipsilateral and contralateral directions, at 45 degrees from the sagittal plane in the anterolateral direction. Center of pressure (COP) coordinates were monitored by using a pressure measurement system as well as a force platform under seat. MAIN OUTCOME MEASURES: Trajectory of COP, maximal distance covered by COP, maximal velocity of COP; and the index of asymmetry between right and left maximal pressure under ischial tuberosities. RESULTS: The generic contoured cushion allowed the COP to cover significantly (p <.02) a larger distance (81 +/- 28mm) when compared with the air flotation (63 +/- 25mm) or the flat foam (61 +/- 29mm) cushions. The COP velocity was significant (p <.05) for the generic contoured cushion (.14 +/-.05m/s) versus the air flotation (.10 +/-.04m/s) or the flat-foam (.10 +/-.03m/s) cushions. The index of asymmetry was higher for the generic contoured and the flat foam cushions. During reaching, maximal pressure under ipsilateral ischial tuberosity was significantly higher for the flat foam (275 +/- 70mmHg) and the generic contoured (235 +/- 81mmHg) cushions, when compared with the air flotation cushion (143 +/- 51mmHg). CONCLUSION: Seat cushions can significantly affect sitting balance during reaching tasks. This study provided an objective method to assess the dynamic stability of wheelchair users when they perform activities of daily living requiring reaching. These findings have implications for wheelchair seating recommendations, especially seat cushion selection.

Effects of upper and lower limb static exertions on global synkineses in hemiparetic subjects.

OBJECTIVES: Global synkineses are nonpurposive pathological involuntary muscle activities or movements elicited at several or all of the joints of the affected limb or limbs during voluntary forceful resisted contractions. The purpose of this study was to assess the effect of upper and lower limb exertions on manifestations of upper limb global synkineses in hemiparetic subjects. DESIGN: Involuntary muscle activities on the affected upper limb of 11 hemiparetic subjects and on the left or right upper limb of 10 control subjects were recorded using surface electromyography during successive bilateral maximal ankle exertions and during contralateral grips. RESULTS: Significant differences in the level of involuntary electromyography (EMG) activities were observed between experimental conditions (ANOVAs, p < 0.05). EMG levels in hemiparetic subjects were significantly higher during contralateral grip tasks than during the ankle exertions. CONCLUSION: These results suggest that upper limb global synkinases are more prevalent in specific tasks and that this task specificity may reflect the neurophysiological mechanisms involved in the generation of global synkinases.

Maximal grip force in chronic stroke subjects and its relationship to global upper extremity function.

OBJECTIVES: Previous studies have shown that recovery of recordable grip strength in acute stroke subjects is one of the most sensitive assessments of initial upper limb recovery and a good prognostic factor for latter recovery. The objectives of this study were to test the reliability of maximal voluntary grip force (MVGF) measures and evaluate the relationship between paretic grip strength deficit and paretic upper extremity function in chronic stroke subjects. DESIGN: Over a three-week period, bilateral MVGF was assessed three times with a modified strain gauge dynamometer in 15 chronic stroke subjects and 10 control subjects. The paretic MVGF deficit was expressed in relation to the MVGF of the nonaffected hand. OUTCOME MEASURES: Upper extremity function in stroke subjects was measured using the Fugl-Meyer, the upper extremity performance test for the elderly (TEMPA), Box and Block and finger-to-nose tests. RESULTS: MVGF measures in both groups of subjects demonstrated good reliability (intraclass correlation, ICC >0.86) and low standard error measurements (SEM). The paretic MVGF of the stroke subjects was greatly impaired in comparison to the control subjects. Results of linear and quadratic regressions analyses show that this impairment was significantly correlated (p <0.01) with the performance of the stroke subjects on the four upper extremity function tests. The percentages of variances explained by the MVGF deficit on all four upper extremity tests varied from 62% to 78% for the linear regressions and from 72% to 93% for the quadratic regressions. CONCLUSIONS: These results suggest that the paretic maximal grip strength, normalized with the maximal grip strength on the nonaffected side, appears to be a valuable outcome measure of upper extremity function in chronic stroke subjects.

Description of a new motor re-education programme for the paretic lower limb aimed at improving the mobility of stroke patients.

OBJECTIVE: To describe and examine the feasibility of a new treatment approach for the paretic lower limb and to explore its effectiveness in one chronic hemiparetic stroke subject. DESIGN: Case report. The treatment was conducted three times per week over a period of six weeks. The mobility of the patient was assessed prior to the treatment, at the end of the treatment and at a six-week follow-up. SETTINGS: The study was carried out at the research centre of the Institut de réadaptation de Montréal. The treating therapist was an experienced rehabilitation professional as was the assessor, who worked at a different rehabilitation centre. INTERVENTIONS: The motor re-education programme was based on the use of a static dynamometer that measures the linear external forces produced at the ankle level. A computer program provided the subject with constant feedback on the direction and intensity of the applied force. In each treatment session, the subject was asked to produce several submaximal efforts in 16 specific directions. Both the intensity and the number of repetitions were gradually increased. OUTCOME MEASURES: In addition to force production measurements, three clinical assessments of mobility were used: the Timed 'Up and Go', the comfortable gait speed and a 2-minute walk test. RESULTS: The maximal static linear forces produced by the subject increased through the treatment for all directions of effort, but differences were observed amongst directions. During the treatment programme, the subject improved his performance at the three clinical assessments. Even if some of the functional gain was lost at the follow-up, the mobility was still considerably improved as compared to baseline values. CONCLUSION: This study demonstrated the applicability of the treatment programme to a stroke subject. The results seem very promising and encourage further investigation in order to assess more rigorously the effectiveness of this new approach.

Analysis of the clinical factors determining natural and maximal gait speeds in adults with a stroke.

The objective of this study was to identify the most important clinical variables determining gait speed in persons with stroke. Sixteen chronic stroke subjects (mean age, 47.9 (+/-15.6) yr; mean time post-stroke, 43.9 (+/-36.5) mo) able to walk independently without a brace participated in the study. The impairments in motor function, sensation of the paretic lower limb, and balance were evaluated with the Fugl-Meyer Assessment. A spasticity index was used to assess the muscle tone of the plantarflexors. The maximal strengths in plantarflexion and hip flexion were measured with a Biodex dynamometric system. Cinematography and foot-contact data collected on the paretic side were used to determine the comfortable and maximal gait speeds. The level of association between gait speeds and the clinical variables were first examined with Pearson's correlation coefficients and, then, with multiple linear regression analyses using the stepwise method. Results revealed that the motor function of the lower limb, balance, and hip flexion strength were significantly related to comfortable and maximal gait speeds (0.5 < r < 0.88; P < 0.05). For the comfortable gait speed, the regression analysis selected only the hip flexor strength as a significant variable (R2 = 0.69). For maximal gait speed, the variables retained were hip flexor strength, sensation at the lower limb, and plantarflexor strength (R2 = 0.85). The present results suggest that strength and sensation at the lower limb are important factors to consider in determining the gait capacity of chronic stroke subjects.

Plantarflexor weakness as a limiting factor of gait speed in stroke subjects and the compensating role of hip flexors.

OBJECTIVE: To determine, using the Muscular Utilization Ratio (MUR) method, whether plantarflexor weakness is among the factors preventing stroke subjects from walking at faster speeds. Potential compensations by the hip flexors were also examined. DESIGN: A convenience sample of 17 chronic stroke subjects in a context of a descriptive study. BACKGROUND: Gait speed is correlated with the residual strength of the muscles involved in gait in stroke subjects. However, it has not been established if this residual strength limits gait speed. METHODS: Kinetic and kinematic data for comfortable and maximal gait speeds were collected on the paretic side, and were used to determine the moments in plantarflexion (mechanical demand: MUR numerator) during the push-off phase. The maximal potential moment (MUR denominator) of the plantarflexors during gait was predicted using an equation derived from dynamometric data collected with a Biodex system. The MURs of the plantarflexors were then calculated at every 1% interval of the push-off phase. The pull-off phase of gait and the hip flexor strength were also examined. RESULTS: Ten subjects of the sample had a MUR value between 80 and 150% at maximal gait speed. These subjects produced the lowest peak torques in plantarflexion. Each of the four fastest subjects of this group had a large hip flexion moment during the pull-off phase of gait and produced high hip flexion torque values on the dynamometer. Each of the seven remaining subjects had a MUR value under 70% when they walked at maximal speed. CONCLUSIONS: Weakness of the plantarflexors should be considered as one factor limiting gait speed in 10 hemiparetic subjects. Some subjects with weak plantarflexors could walk rapidly because they compensated with the hip flexors. For the remaining stroke subjects, factors other than weakness of the plantarflexors have to be considered in order to explain the reduction in their gait speed.

The interrater reliability of force measurements using a modified sphygmomanometer in elderly subjects.

BACKGROUND AND PURPOSE: Physical therapists working with elderly people require an instrument that provides reliable force measurements and can be used in a clinical setting. The modified sphygmomanometer has been identified as potentially fulfilling these requirements, yet there is an absence of research on the reliability of measurements taken with this instrument on elderly patients. This study was undertaken to investigate the interrater reliability of force measurements, in a group of elderly subjects, using a modified sphygmomanometer. SUBJECTS: Thirty-six hospitalized subjects (mean age=75.28 years, SD=9.43, range=62-95) participated in the study. METHODS: With the modified sphygmomanometer, 3 examiners evaluated the isometric force of the elbow extensors and hip extensors using a break test and a make test, respectively. RESULTS: Intraclass correlation coefficients (2,1) reflecting reliability were .87 for the elbow extensors and .65 for the hip extensors. The estimation of the components of variance for hip extensors revealed that these results were due in part to the raters but that random error contributed to a much larger extent. CONCLUSION AND DISCUSSION: The modified sphygmomanometer appears to be practical to use, and the high correlations found in this study for the elbow extensors suggest that reliable measurements can be obtained with this instrument. Further research is needed, however, to specify the manner in which the modified sphygmomanometer can be used when assessing different muscle groups.

A static dynamometer measuring simultaneous torques exerted at the upper limb.

The majority of available dynamometers are designed to measure force or torque in one specific direction, one joint at a time. For the quantification of motor incoordination in neurological patient populations, these dynamometers provide limited information about the global behavior of the limb under investigation. This report describes the potential use and function of a static dynamometer measuring torques exerted simultaneously at the shoulder (flexion-extension, abduction-adduction, internal-external rotation), elbow (flexion-extension), and forearm (pronation-supination). Orthogonal forces were measured at the arm and wrist using strain gauge transducers interfaced with a laboratory computer. The lever arms were specified to a software program and the joint torques were calculated in real time according to static equilibrium equations. The use of the dynamometer is illustrated by characterizing for one hemiparetic subject, the joints torques recorded at the shoulder, elbow, and forearm during isolated submaximal grip exertions at different force levels on both sides. The torques generated at the shoulder, elbow and forearm during the hand grip tasks on the affected side were significantly higher than those obtained on the nonaffected side and increased with the grip force level. These differences probably reflect the loss of movement selectivity observed following a lesion in the central nervous system. Further studies are currently being undertaken in neurological patient populations to characterize and quantify motor deficits using this dynamometer. As a long term goal, we hope that the method and technologies described here will contribute to the evaluation and rehabilitation of these populations.

Microsomal enzyme activity, glutathione S-transferase-placental form expression, cell proliferation, and vitamin A stores in livers of rats consuming Great Lakes salmon.

Male and female Sprague-Dawley rats were fed diets incorporating lyophilized chinook salmon obtained from Lake Ontario and Lake Huron. After 70 days, females were bred and the progeny (F1) were reared on the same fish-based diets as the adults (F0). After 78-133 days on the diets, males and females of both generations were sacrificed and hepatic microsomal enzyme activities determined, along with glutathione S-transferase-placental form (GSTP) expression and hepatic cellular proliferation. Hepatic P450 enzyme activities (MROD, EROD, PROD, BROD, and aminopyrine) were increased significantly by fish diets from both sources. Increases in hepatic enzyme activity were greatest for fish caught from Lake Ontario and reflected the total levels of organochlorine contaminants in the fish. GSTP and cell proliferation rates did not show any diet-related or dose-related changes. Vitamin A stores were analyzed as the concentration of liver retinyl palmitate. In rats receiving the highest TEQ dose (i.e., 20% Lake Ontario fish diet), vitamin A stores were significantly lower in F0 adults, F1 weanlings, and F1 adult females.