Manual Dexterity Test Research Articles

Coin Rotation Task (CRT): A New Test of Motor Dexterity

Coin-rotation task (CRT), a measure of rapid, coordinated finger movements, was devised as a convenient, easily administered bedside test of motor dexterity; however, very little psychometric data exist regarding this task. The current project was undertaken to (a) provide preliminary normative data, (b) examine the convergent and discriminant validity of the task when compared with other standardized motor measures, and (c) examine the diagnostic accuracy of the CRT. The sample of 86 male participants included 60 controls and 26 patients with unilateral lesions of the left (n = 13) and right (n = 13) hemispheres. The CRT was not significantly correlated with age or education; non-adjusted left- and right-hand normative data are provided. The CRT demonstrated good convergent and divergent validity when compared with other standardized motor measures. The CRT was successful in differentiating control and brain damaged groups with mild motor impairment, and demonstrated an overall classification rate of 84.9%. Levels of sensitivity and specificity of the CRT were comparable with or better than other standardized tests of manual dexterity. The CRT offers a valid, quick, and convenient bedside measure of subtle motor impairment.

Decrements Encountered when Wearing Hazardous Materials Gloves

Hazardous materials gloves (HAZMAT) are frequently worn when performing clinical technical skills, but it is unclear how sensory and motor performance is affected in these circumstances. In Experiment 1, two timed standardized manual dexterity tests, and a test of sensory function were administered. Glove use resulted in a decreased ability to ma- nipulate small objects and a decreased sensitivity to light touch. However, the ability to manipulate objects with a tool was unaffected by the glove. In Experiment 2, the objects were instrumented with a force/torque sensor and the coefficient of friction between the digits and the object was estimated. An elevation of grasping forces and an increased slipperiness be- tween the digits and the object were observed. In Experiment 3, fingertip placement was quantified with pressure sensitive sheets and revealed a misalignment of the digits. Collectively these results suggest that impairments to motor performance when wearing a glove might be related to misalignment of the digits, associated with sensory decrement. These results can be used in the formulation of protocols for professionals wearing HAZMAT gloves and in the design of tools and HAZ- MAT garments.

Anti‐Nogo‐A antibody treatment promotes recovery of manual dexterity after unilateral cervical lesion in adult primates – re‐examination and extension of behavioral data

In rodents and nonhuman primates subjected to spinal cord lesion, neutralizing the neurite growth inhibitor Nogo-A has been shown to promote regenerative axonal sprouting and functional recovery. The goal of the present report was to re-examine the data on the recovery of the primate manual dexterity using refined behavioral analyses and further statistical assessments, representing secondary outcome measures from the same manual dexterity test. Thirteen adult monkeys were studied; seven received an anti-Nogo-A antibody whereas a control antibody was infused into the other monkeys. Monkeys were trained to perform the modified Brinkman board task requiring opposition of index finger and thumb to grasp food pellets placed in vertically and horizontally oriented slots. Two parameters were quantified before and following spinal cord injury: (i) the standard ‘score’ as defined by the number of pellets retrieved within 30 s from the two types of slots; (ii) the newly introduced ‘contact time’ as defined by the duration of digit contact with the food pellet before successful retrieval. After lesion the hand was severely impaired in all monkeys; this was followed by progressive functional recovery. Remarkably, anti-Nogo-A antibody-treated monkeys recovered faster and significantly better than control antibody-treated monkeys, considering both the score for vertical and horizontal slots (Mann–Whitney test: P = 0.05 and 0.035, respectively) and the contact time (P = 0.008 and 0.005, respectively). Detailed analysis of the lesions excluded the possibility that this conclusion may have been caused by differences in lesion properties between the two groups of monkeys.

Effects of Waking Time and Breakfast Intake Prior to Evaluation of Psychomotor Performance in the Early Morning

Many studies conducted in the field of chronobiology report diurnal fluctuation in cognitive and physical performance that occurs in phase with the body temperature circadian rhythm. Waking time and whether or not breakfast is consumed are currently considered to influence the diurnal fluctuation in data collected in the morning at 06∶00 h and evening at 18∶00 h. Nineteen male subjects participated in four test sessions to examine if wake‐up time (04∶00 h or 05∶00 h) and eating or not eating breakfast influence psychomotor performance capacity at 06∶00 h. All four sessions were separated by ≥36 h and were completed in a counterbalanced order. Each test session comprised sign cancellation, Epworth Sleepiness Scale, simple reaction time, and manual dexterity tests. Most of the results indicate that psychomotor performance when evaluated at 06∶00 h under each of the four different study situations (two waking times and two breakfast conditions) is not statistically significantly different. Consequently, previous results that documented diurnal fluctuations in morning and evening performance capacities, with test sessions at 06∶00 h, are confirmed. Being less efficient in the early morning than in the afternoon potentially exposes people to elevated risk of accident and injury at this time of the day. Prior waking time and/or consumption of a light meal, plus other countermeasures mentioned in the literature, are insufficient to prevent this risk.

Manual Performance Deterioration in the Cold Estimated Using the Wind Chill Equivalent Temperature

Manual performance during work in cold and windy climates is severely hampered by decreased dexterity, but valid dexterity decrease predictors based on climatic factors are scarce. Therefore, this study investigated the decrease in finger- and hand dexterity and grip force for nine combinations of ambient temperature (-20, -10 and 0 degrees C) and wind speeds (0.2, 4 and 8 m x s(2)), controlled in a climatic chamber. Finger dexterity was determined by the Purdue pegboard test, hand dexterity by the Minnesota manual dexterity test and grip force by a hand dynamometer. Twelve subjects with average to low fat percentage were exposed to cold air for one hour with and without extra insulation by a parka. The subjects were clothed in standard work clothing of the Royal Netherlands Air Force for cold conditions. Extra insulation did affect cold sensation but not manual performance. The deterioration in manual performance appeared to be strongly dependent upon Wind Chill Equivalent Temperature (WCET) and the square root of exposure time (r=0.93 for group average). These simple models may be valuable to assess problems with work in the cold, but more work should be done to determine critical values in dexterity for a wide variety of operational tasks.

Effects of acute insulin-induced hypoglycaemia on psychomotor function: people with type 1 diabetes are less affected than non-diabetic adults

We examined the effects of acute insulin-induced hypoglycaemia on psychomotor function in non-diabetic volunteers and in adults with type 1 diabetes. Non-diabetic adults (n = 20) and adults with type 1 diabetes mellitus (n = 16) each underwent a euglycaemic-hyperinsulinaemic glucose clamp on two separate occasions. Arterialised blood glucose was maintained for 1 h at either 4.5 mmol/l (euglycaemia) or 2.5 mmol/l (hypoglycaemia). During this time participants underwent neuropsychological tests to assess psychomotor function. During hypoglycaemia the non-diabetic participants showed a significant deterioration in the following: (1) four-choice reaction time (p = 0.008); (2) grooved pegboard (a test of manual dexterity; p = 0.004); (3) hand steadiness (p = 0.003); (4) pursuit rotor (a test of fine motor function, attention and coordination; p = 0.018); and (5) test of total body coordination (p = 0.004). No significant differences were observed between euglycaemia and hypoglycaemia in hand-grip (p = 0.897) and line tracing time (p = 0.480) tests. In type 1 diabetes mellitus patients, only four-choice reaction time (p = 0.023) and pursuit rotor (p = 0.045) were impaired significantly during hypoglycaemia. Although acute hypoglycaemia caused significant impairment of several psychomotor functions in non-diabetic adults, a lower magnitude of impairment was observed in those with type 1 diabetes. The mechanism underlying this discrepant effect of hypoglycaemia on psychomotor function remains unknown, but may be related to the difference in sympathoadrenal activation observed between the groups. People with type 1 diabetes may also have had a behavioural advantage of over non-diabetic participants derived from their previous exposure to hypoglycaemia or potentially the disparate results arose from hypoglycaemia-induced cerebral adaptation.

Effect of Training on Upper-Extremity Prosthetic Performance and Motor Learning: A Single-Case Study

Dromerick AW, Schabowsky CN, Holley RJ, Monroe B, Markotic A, Lum P. Effect of training on upper-extremity prosthetic performance and motor learning: a single-case study. Objectives To examine the impact of a new prosthesis on an experienced and highly motivated prosthetic limb user, to evaluate the effects of training and the ability of clinical measures to detect change, and to gain insight into the mechanisms by which improvement occurs. Design A single-case study. Setting An outpatient clinic. Participant A bilateral high-arm amputee (right shoulder disarticulation, left above elbow). Interventions Provision of new prosthesis and occupational therapy. Main Outcome Measures Action Research Arm Test, box and block test of manual dexterity, Jebsen-Taylor Hand Function Test, and speed and accuracy of reaching movements with and without visual guidance. Results In this experienced prosthesis user, provision of a new prosthesis led to an immediate worsening in functional limitation. With training, the subject recovered his baseline status and then exceeded it in both proximal and distal function. All study clinical measures detected change, but the change detected varied as much as 300-fold depending on the measure chosen. The clinical improvements were associated with modest improvements in the speed of reaching but not the accuracy of reaching under visual guidance. Improvements in reaching accuracy without visual guidance were seen after 10 trials, suggesting that some motor learning had occurred. Conclusions Provision of a new prosthesis can cause functional decline even in an experienced user; this decline can be reversed with training. There is wide variability in sensitivity to change among functional limitation measures. Although some training-related improvements may have been due to increased speed and accuracy of reaching without visual guidance, skill in prosthesis use also plays a role.

Correlation of Manual Dexterity With USMLE Scores and Medical Student Class Rank

Surgical programs often rely on objective measures of medical school cognitive performance, including United States Medical Licensing Exams (USMLE) scores and class rank, to predict success of an applicant in their training program. Although job applicants in non-medical fields often undergo dexterity testing prior to being hired, this has not been widely used in the selection process for surgical residency applicants. Thus, successful identification of applicants likely to succeed in surgical fields remains elusive. Given this difficulty, we wondered if performance on tests of manual dexterity would correlate with USMLE board scores and medical school class rank. Fourth year medical students underwent a clinical study of dexterity testing using the Stromberg Dexterity Test (gross motor), the O'Conner Tweezer Test (fine motor), and the MIST-VR laparoscopic simulator (Mentice Corporation, Gothenberg, Sweden). Performance times were compared with USMLE Step I & II scores and class rank, as well as a self-assessment of manual dexterity. A total of 113 medical students participated. Gross motor dexterity was significantly correlated with class rank (P = 0.04) and USMLE Step I score (P = 0.04). Fine motor dexterity and MIST-VR performance did not correlate with class rank or USMLE scores. Self-assessment of good manual dexterity correlated with faster performance times on the MIST-VR laparoscopic simulator (0.0174). Gross motor skill is associated with objective measures of medical school cognitive performance, such as class rank and USMLE scores. Furthermore, self-assessment of dexterity may predict baseline laparoscopic abilities. Further research is necessary to determine whether such dexterity testing could be helpful in identifying applicants who possess the ability to develop into competent surgeons.

Effect of biofeedback accompanying occupational therapy and functional electrical stimulation in hemiplegic patients

The objective of this study was to determine the effect that electromyographic biofeedback (EMG-BFB), used in conjunction with occupational therapy (OT) and functional electrical stimulation (FES), has on spasticity, range of motion, and upper extremity function in hemiplegic patients. A total of 59 patients treated at a university-based rehabilitation centre were studied. Of those 59 patients, 31 received twice-weekly sessions of OT+FES, together with weekly sessions of EMG-BFB, and 28 received only the twice-weekly sessions of OT+FES. The patients were evaluated at baseline, at 6 months, and at 12 months, using the hand function test, the Minnesota manual dexterity test, the joint range of motion scale, and the modified Ashworth scale. At 6 months, the patients receiving EMG-BFB presented significantly greater improvement in upper extremity function than those receiving only OT+FES. Incorporating EMG-BFB into the treatment regimen had a positive effect on the range of motion and on the recovery of upper extremity function in hemiplegic patients. Biofeedback training might represent an important therapeutic tool for the rehabilitation of stroke patients.

QS48. Correlation Between Performance on Tests of Manual Dexterity and Usmle Board Scores and Medical School Class Rank

QS48. Correlation Between Performance on Tests of Manual Dexterity and Usmle Board Scores and Medical School Class Rank

Assessment of Containment Equipment Using a Novel Test to Determine the Effect of Containment on Laboratory Accuracy

A newly developed test of operator manual dexterity in containment equipment more closely replicates standard laboratory techniques than previously used commercial pegboard dexterity tests. The test measures pipetting accuracy and has been developed and fully validated to assess the effect of containment equipment on laboratory techniques. Intra-assay variation had a mean of 1.4%; inter-assay variation had a mean of 3% within day and 3.6% between days. The test retest coefficient, using Pearson's correlation, was 0.898, (p=0.001). The test was then used to measure pipetting accuracy in class II and III biological safety cabinets (BSCs). When experienced users took the tests in the two types of BSCs, their accuracy did not differ significantly. External factors (age, experience, glove size, gender) did not influence technical accuracy within the BSCs. The participants' level of pipetting accuracy is an inherent ability not influenced significantly by the factors measured, including the type of BSC used. Operators did; however, take significantly longer to complete tasks in the class III BSC.

Effect of finger tracking combined with electrical stimulation on brain reorganization and hand function in subjects with stroke

Synergism of rehabilitative interventions could maximize recovery following stroke. We examined whether the combination of peripherally initiated electrical stimulation of finger extensors and centrally operating finger tracking training could accentuate brain reorganization and its relationship to recovery, beyond the effects of either treatment alone. Twenty subjects with stroke were randomly assigned to an electrical stimulation (ES), tracking training (TR) or combination (CM) group. Each group was trained for ten 1-h sessions over 2-3 weeks. Pretest and posttest measurements consisted of the Box and Block and Jebsen Taylor tests of manual dexterity and a finger tracking test that was performed during functional magnetic resonance imaging (fMRI). fMRI variables included laterality index and BOLD signal intensity of primary motor (M1), primary sensory (S1), sensorimotor (SMC) and premotor (PMC) cortices as well as, supplementary motor area (SMA). ES and CM groups improved on dexterity, whereas the TR group did not. Improvement in the CM group was not greater than the other two groups. Subjects who had an intact M1 showed greater functional improvement than those who had direct involvement of M1. fMRI analysis did not yield significant changes from pretest to posttest. In the CM group only, functional improvement was positively correlated with laterality index change in M1, S1, SMC and PMC, indicating greater ipsilesional control and was negatively correlated with BOLD Signal Intensity change in ipsilesional S1 and SMA, indicating neurophysiological trimming of irrelevant neurons. The correlational results suggest that the combined intervention may be more influential on brain reorganization than either treatment alone but a larger sample size, longer duration of training, or a restricted inclusion of stroke location and volume may be needed to demonstrate a difference in efficacy for producing behavioral changes.

New targets for established proteins: exploring G-CSF for the treatment of stroke

Several recent reports describe the efficacy of the hematopoietic factor granulocyte-colony-stimulating factor (G-CSF) in models of stroke and neurodegeneration. Here, we discuss the role of G-CSF as a novel type of multifactorial drug with which to treat stroke, and describe aspects of its modes of action in stroke, in addition to the relationship between clinical trials and the preclinical dataset. Neuroprotective activity in stroke models seems to be based on a direct anti-apoptotic activity in neurons that is mediated by the neuronally expressed G-CSF receptor. Explanations for the long-term effects that improve recovery in different experimental models of stroke include the enhancement of neurogenesis in the adult brain and the stimulation of blood vessel formation. Additional beneficial effects might be based on systemic influences on immunocompetence and inflammation parameters, and the activation of bone-marrow-derived stem cells. Several clinical trials have been initiated in stroke patients, mainly to demonstrate the safety of G-CSF in this setting.

Testosterone levels and cognitive functioning in women with polycystic ovary syndrome and in healthy young women

We investigated the possible influence of testosterone (T) on cognitive functioning in women with polycystic ovary syndrome (PCOS), an endocrine disorder associated with elevated levels of free testosterone (free T). Performance on a battery of neuropsychological tests in 29 women with elevated free T levels due to PCOS was compared to the performance of 22 age- and education-matched, healthy control women with free T levels in the normal female range. Women with PCOS had significantly higher levels of free T (estimated by the free androgen index) and demonstrated significantly worse performance on tests of verbal fluency, verbal memory, manual dexterity, and visuospatial working memory than the healthy control women. No differences between the groups were found on tests of mental rotation, spatial visualization, spatial perception, or perceptual speed. These results suggest that, in women, elevations in free T may be associated with poorer performance on cognitive tasks that tend to show a female advantage.

Neuropsychological dysfunction related to earlier occupational exposure to mercury vapor

We assessed the neuropsychological test performances of 26 patients (mean age = 41.5 +/- 6.1 years; mean years of education = 9.8 +/- 1.8; 20 males) diagnosed with chronic occupational mercurialism who were former workers at a fluorescent lamp factory. They had been exposed to elemental mercury for an average of 10.2 +/- 3.8 years and had been away from this work for 6 +/- 4.7 years. Mean urinary mercury concentrations 1 year after cessation of work were 1.8 +/- 0.9 microg/g creatinine. Twenty control subjects matched for age, gender, and education (18 males) were used for comparison. Neuropsychological assessment included attention, inhibitory control, verbal and visual memory, verbal fluency, manual dexterity, visual-spatial function, executive function, and semantic knowledge tests. The Beck Depression Inventory and the State and Trait Inventory were used to assess depression and anxiety symptoms, respectively. The raw score for the group exposed to mercury indicated slower information processing speed, inferior performance in psychomotor speed, verbal spontaneous recall memory, and manual dexterity of the dominant hand and non-dominant hand (P < 0.05). In addition, the patients showed increased depression and anxiety symptoms (P < 0.001). A statistically significant correlation (Pearson) was demonstrable between mean urinary mercury and anxiety trait (r = 0.75, P = 0.03). The neuropsychological performances of the former workers suggest that occupational exposure to elemental mercury has long-term effects on information processing and psychomotor function, with increased depression and anxiety also possibly reflecting the psychosocial context.

The Effect of Microbiological Containment Systems on Dexterity

Microbiology laboratories use containment equipment such as safety cabinets and isolators or respiratory protective equipment to protect workers against aerosol infection hazards. There is a perception among microbiologists that the use of containment equipment reduces dexterity to a point where the risks associated with using sharps are increased. Thus, in a situation where it is essential to use sharps, the use of respiratory protection is frequently the favored method of operator protection. Using three methods of manual dexterity testing, the effect of latex gloves, a positive pressure respirator, and three forms of containment equipment, (a Class II safety cabinet, a half suit, and a flexible film isolator) were tested against performance in these tests using bare hands in 10 subjects. The study was extended to additionally assess Class III cabinets using 20 subjects. With the exception of latex gloves, the personal protective equipment and containment equipment all had a statistically significant detrimental effect on manual dexterity compared with working solely with bare hands. The use of containment systems, especially barrier containment systems such as Class III cabinets and isolators, significantly reduces dexterity and may increase the chance of accidents. The use of positive pressure respirators with double gloves also affects dexterity but to a lesser extent. The use of sharps should be minimized within containment equipment. Risk assessment may be required to address the comparative risk of aerosol and needlestick infection with different agents to choose the most appropriate containment systems.

Effects of the pharmacologic manipulation of testosterone on cognitive functioning in women with polycystic ovary syndrome: A randomized, placebo-controlled treatment study

In a previous study, we found that women with polycystic ovary syndrome (PCOS), an endocrine disorder characterized by chronic hyperandrogenism, performed more poorly than healthy, matched controls on a number of neuropsychological tests, in particular tests of verbal fluency, verbal memory, manual dexterity, and visuospatial working memory. This randomized, placebo-controlled trial was undertaken to investigate whether pharmacologic manipulation of free testosterone (free T) levels in women with PCOS might affect their performance on cognitive tests. Nineteen women with PCOS completed a battery of neuropsychological tests before and after 3 months of treatment with either an anti-androgen (cyproterone acetate) plus estrogen or with a placebo. Hormone treatment of women with PCOS caused a significant reduction in their free T levels but did not affect performance on tests visuospatial ability, verbal memory, manual dexterity, or perceptual speed. Women treated with hormone therapy did, however, demonstrate an improvement in their performance on a test of verbal fluency compared to their pre-treatment scores. These findings suggest that changes in free T levels do not have a significant impact on cognitive performance in women with PCOS, although reductions in free T may be beneficial for verbal fluency.

Assessment of fine motor control in patients with occupation-related lateral epicondylitis

Lateral epicondylitis (LE) is a common overuse injury related to a mechanical overload of the wrist extensors’ origin; however, some patients also complain of clumsiness suggesting a possible motor control problem. The purpose of this study was to examine for differences in fine motor control ability between subjects with LE and matched control subjects. Subtests of the Purdue Pegboard Test (PPT) and the Complete Manual Dexterity Test (CMDT) were administered to 28 subjects with LE, and 28 age, gender, and hand dominance-matched control subjects. The LE group demonstrated a significant decrease in fine motor control ability on both measures, compared with the control group on both the PPT, F(1,52)=9.98, P=0.003, and the CMDT, F(1,52)=18.11, P=0.001. There appeared to be no effect for the length of time since injury. There were significant differences in fine motor control ability between individuals with LE and a matched control group for both measures used. These results suggest that tests of fine motor control should be considered in the assessment of clients with LE. The mechanism related to the deficit is unknown and warrants further research.

Motor Incoordination Response to Methylphenidate in Children with ADHD

Source: Flapper BCT, Houwen S, Schoemaker MM. Fine motor skills and effects of methylphenidate in children with attention-deficit hyperactivity disorder and developmental coordination disorder. Dev Med Child Neurol. 2006;48:165–169; doi:10.1017/S0012162206000375The manual dexterity subtests of the Movement Assessment Battery for Children and handwriting and computerized graphomotor tasks were used to compare motor skills in a group of 12 children (11 males) with attention-deficit hyperactivity disorder (ADHD) and developmental coordination disorder (DCD) to those in 12 controls at University Medical Centre Groningen, the Netherlands. ADHD-DCD children had more severely impaired fine motor abilities than control children: they made more errors and were slower in completing manual dexterity tests (P=.001), their handwriting was poorer (P=.002), and on a flower trail graphomotor task, they drew more rapidly and fluently but were less accurate than controls (P=.002). When treated with methylphenidate, manual dexterity in the ADHD-DCD group was improved (P=.003), handwriting quality improved (P=.042), and lines on the graphomotor task were less fluent (P=.028) but more accurate (P=.01). It is estimated that 50% of children with ADHD have comorbid DCD.Dr. Millichap has disclosed no financial relationship relevant to this commentary. This commentary does not contain a discussion of a commercial product/device. This commentary does not contain a discussion of an unapproved/investigative use of a commercial product/device.The prevalence of incoordination and other ”subtle” or ”soft” neurologic abnormalities in children with ADHD was recognized by a National Institutes of Health task force in 1966, when the term “minimal brain dysfunction” (MBD) was coined for the syndrome.1 Subtle abnormal neurological signs include motor impersistence (inability to maintain a motor behavior such as closing the eyes on request), response inhibition deficit (inability to look at an object without picking it up (“he cannot keep his hands to himself”), dyspraxia (loss of dexterity in purposeful moments, as in using scissors), dysgraphia (inability to write or print words and numbers despite normal hand muscle power, essentially a dyspraxia of the hands), synkinesia (mirror movements), incoordination (clumsiness), and graphanesthesia (inability to recognize traced numerals, a cortical sensory deficit). Some of these neurologic signs are now described as part of DCD. These signs were used as outcomes in early controlled trials of methylphenidate in the treatment of ADHD (MBD).2 Improvements in coordination, handwriting, and visual perception, in addition to attention and activity, were documented that were similar to the results obtained in the current report. In the DSM criteria3 for the diagnosis of ADHD, reference to impaired motor performance, clumsiness, and incoordination has been omitted, despite the frequency of these findings. The early concept of an organic or neuro-biologic syndrome4 has been rejected in favor of a symptom diagnosis for ADHD.In Scandinavia, the syndrome of DAMP (deficits in attention, motor control and perception) emphasizes the association of neurologic signs of motor dysfunction, perceptual dysfunction, and attention deficits.5 An overlap of ADHD and DAMP, and the presence of DAMP among children with neurodevelopmental disorders, are also recognized. ADHD, when complicated by incoordination and other symptoms of DCD, may increase the risk of learning and especially language and reading problems.6 The inclusion of questions and tests for incoordination and perceptual dysfunction in the criteria for ADHD would allow a more objective diagnosis and lead to earlier recognition and effective treatment. Perhaps the term “attention deficit hyperactivity & coordination disorder (ADH&CD)” would be more appropriate.ADHD, DCD, ADHD-DCD, DAMP, MND, ADH & CD – this article tested our ability to attend to multiple acronyms! Nonetheless, it did not dampen our interest in monitoring for fine motor improvement in children with ADHD, which may well be a good marker of response to therapy.

Comparison of Patella Lead With Blood Lead and Tibia Lead and Their Associations With Neurobehavioral Test Scores

Lead exposure in adults is associated with worse cognitive function in cross-sectional and longitudinal studies. Previous studies have mainly examined relations with blood lead or cortical bone lead; few have examined trabecular bone lead. We performed a cross-sectional analysis of the relations of patella lead and other lead biomarkers with measures of neurobehavioral and peripheral nervous system function in 652 lead workers. Patella lead was found to be associated with worse performance on seven of 19 tests of manual dexterity, sensory vibration threshold, and depressive symptoms. The associations of patella lead with cognitive function were essentially similar to those with blood lead or tibia lead but of somewhat lower magnitude. In this study, measurement of patella lead did not aid causal inference regarding cognitive effects when compared with blood lead and tibia lead.