Does manual mobilization influence motion coupling patterns in the atlanto-axial joint?

BackgroundA restricted number of publications have reported on the analysis of coupling patterns in the atlanto-axial joint using an in vitro set-up applying pure moments of forces. The aim of this study is to analyze segmental motion coupling patterns during cervical manual mobilization.MethodsThe position and attitudes of sensors mounted on the atlas and axis were traced in nine embalmed and one fresh human spinal specimen using an electromagnetic tracking system. Segmental bony reference points were registered using a 3D-digitizing stylus for the definition of bone embedded coordinate systems.Segmental motion coupling was recorded for the atlanto-axial joints during manual mobilization through the full range of axial rotation and lateral bending.ResultsCoupled motions were described by the direction of the associated motion and by cross-correlation analysis. The results confirm the contra-lateral coupling pattern of axial rotation with lateral bending at C1–C2 observed in previous studies. The cross-correlation analysis offered a more objective interpretation of the coupling pattern for the analysis of the more irregular coupling patterns during lateral bending. Inter-individual differences in coupling patterns were observed.InterpretationsThe presented method provides possibilities for the study of coupled motion during manual diagnostic and therapeutic practice. Practitioners should be aware of the segmental 3D-aspects of manually induced so called planar mobilizations and their possible influence on motion coupling. Motion coupling patterns may be related to specimen specific anatomy.     

Reproducibility of Frankfort Horizontal Plane on 3D Multi-Planar Reconstructed MR Images

Objective

The purpose of this study was to determine the accuracy and reliability of Frankfort horizontal plane identification using displays of multi-planar reconstructed MRI images, and propose it as a sufficiently stable and standardized reference plane for craniofacial structures.

Materials and Methods

MRI images of 43 subjects were obtained from the longitudinal population based cohort study SHIP-2 using a T1-weighted 3D sequence. Five examiners independently identified the three landmarks that form FH plane. Intra-examiner reproducibility and inter-examiner reliability, correlation coefficients (ICC), coefficient of variability and Bland-Altman plots were obtained for all landmarks coordinates to assess reproducibility. Intra-examiner reproducibility and inter-examiner reliability in terms of location and plane angulation were also assessed.

Results

Intra- and inter-examiner reliabilities for X, Y and Z coordinates of all three landmarks were excellent with ICC values ranging from 0.914 to 0.998. Differences among examiners were more in X and Z than in Y dimensions. The Bland–Altman analysis demonstrated excellent intra- as well as inter-examiner agreement between examiners in all coordinates for all landmarks. Intra-examiner reproducibility and inter-examiner reliability of the three landmarks in terms of distance showed mean differences between 1.3 to 2.9 mm, Mean differences in plane angulation were between 1.0° to 1.5° among examiners.

Conclusion

This study revealed excellent intra-examiner reproducibility and inter-examiner reliability of Frankfort Horizontal plane through 3D landmark identification in MRI. Sufficiently stable landmark-based reference plane could be used for different treatments and studies.     

Assessment of renal volume by three-dimensional ultrasonography in pregnant bitches: an experimental study using virtual organ computer-aided analysis

ABSTRACT: BACKGROUND: To assess and to compare the renal volume evolution in bitches during pregnancy by two-dimensional (2D) ultrasonography using the ellipsoid technique (volume?=?length x width x depth x 0.523) and three-dimensional (3D) ultrasonography using the Virtual Organ Computer-aided AnaLysis (VOCAL) method. A longitudinal prospective study was performed with 17 normal Golden Retrievers bitches during pregnancy from heat to the last third of gestation. The ultrasound scans were performed by two veterinarians. The left and right kidneys were assessed in three moments (day 0?=?non-pregnant bitches; days 1st to 20th of pregnancy and days 21st to 40th of pregnancy) by three techniques (ellipsoid; VOCAL 12° and VOCAL 30°). For reproducibility calculations, we used the intraclass correlation coefficient (ICC). RESULTS: The inferential result of the volumes in ANOVA revealed the interaction effect between side and moment (p?=?0.009). The 3D techniques showed, in average, the same renal volumes (p?=?0.137) regardless of the side and moment. Considering the right side, the renal volume in the day 0 was smaller than the day 21st to 40th (p?=?0.029). Considering the left side, the renal volume at day 0 was smaller than the day 1st to 20th (p?=?0.020) and day 21st to 40th (p?=?0.007). It was found good intra observer reproducibility (ICC?>?0.9) and none of the three techniques showed a good inter observer reproducibility (ICC?相似文献   

Quantification of the forearm muscles mechanical properties using Myotonometer: Intra- and Inter-Examiner reliability and its relation with hand grip strength

The primary objective of this study was to investigate the reliability of the myotonometer in the mechanical properties of the forearm muscles [m. extensor carpi radialis brevis (ECRB), and m. flexor carpi ulnaris (FCU)] in healthy individuals. The secondary objective was to investigate the relationship between the handgrip strength and mechanical properties of these forearm muscles. The mechanical properties (muscle tone, stiffness, and elasticity) of the ECRB and FCU were measured using the MyotonPRO device. Examiner 1 performed two sets of measurements with a time interval of 30 min to determine intra-examiner reliability. Examiner 2 performed measurements during the interval between the two sets of examiner 1. The intra- and inter-examiner reliabilities were excellent (ICC˃0.82) for muscle tone, stiffness, and elasticity of the FCU. Both intra- and inter-examiner reliability in the evaluation of ECRB muscle tone, elasticity, and stiffness was moderate to excellent (ICCs = 0.56–0.98). The muscle tone and stiffness properties of the FCU were positively correlated with the handgrip strength (p <.05). The study findings indicate that the MyotonPRO device is a reliable tool to quantify ECRB, and FCU muscles mechanical properties in healthy individuals.     

Reliability of Three-Dimensional Pseudo-Continuous Arterial Spin Labeling MR Imaging for Measuring Visual Cortex Perfusion on Two 3T Scanners

Cerebral blood flow (CBF) in the human primary visual cortex is correlated with the loss of visual function in neuro-ophthalmological diseases. Advanced three-dimensional pseudo-continuous arterial spin labeling (3D pCASL), as a non-invasive method to access the CBF, can be a novel measurement to detect the visual cortex. The objective of the study was to assess the intra- and inter-scanner reliability of 3D pCASL of the visual cortex in healthy adults and suggest the selection of different post-labeling delay times (PLDs). For this reason, 3D pCASL was conducted in two 3.0T MR three times with twelve healthy volunteers at an interval of 10–15 days. The 1st and 3rd tests were performed on scanner-1, and the 2nd test was performed on scanner-2. The value of the CBF was abstracted from the visual cortex with two PLDs. The intra- and inter-scanner reliability and reproducibility were evaluated with the intraclass correlation coefficient (ICC) and Bland-Altman plots. By estimating the mean value of the CBF in the visual cortex, the intra-scanner results demonstrated the higher reliability (ICC for PLD = 1.5 second presented at 0.743 compared with 0.829 for PLD = 2.5 seconds), and the Bland-Altman plots showed the reproducibility at a longer PLD. We conclude that the calibrated 3D pCASL approach provides a highly reproducible measurement of the CBF of the visual cortex that can serve as a useful quantitative probe for research conducted at multiple centers and for the long-term observation of the clinical effects of neuro-opthalmological diseases.     

Reproducibility of electronic tooth colour measurements

Clinical methods of investigation, such as tooth colour determination, should be simple, quick and reproducible. The determination of tooth colours usually relies upon manual comparison of a patient's tooth colour with a colour ring. After some days, however, measurement results frequently lack unequivocal reproducibility. This study aimed to examine an electronic method for reliable colour measurement. The colours of the teeth 14 to 24 were determined by three different examiners in 10 subjects using the colour measuring device Shade Inspector. In total, 12 measurements per tooth were taken. Two measurement time points were scheduled to be taken, namely at study onset (T(1)) and after 6 months (T(2)). At either time point, two measurement series per subject were taken by the different examiners at 2-week intervals. The inter-examiner and intra-examiner agreement of the measurement results was assessed. The concordance for lightness and colour intensity (saturation) was represented by the intra-class correlation coefficient. The categorical variable colour shade (hue) was assessed using the kappa statistic. The study results show that tooth colour can be measured independently of the examiner. Good agreement was found between the examiners.     

Repeatability and reproducibility of decisions by latent fingerprint examiners

The interpretation of forensic fingerprint evidence relies on the expertise of latent print examiners. We tested latent print examiners on the extent to which they reached consistent decisions. This study assessed intra-examiner repeatability by retesting 72 examiners on comparisons of latent and exemplar fingerprints, after an interval of approximately seven months; each examiner was reassigned 25 image pairs for comparison, out of total pool of 744 image pairs. We compare these repeatability results with reproducibility (inter-examiner) results derived from our previous study. Examiners repeated 89.1% of their individualization decisions, and 90.1% of their exclusion decisions; most of the changed decisions resulted in inconclusive decisions. Repeatability of comparison decisions (individualization, exclusion, inconclusive) was 90.0% for mated pairs, and 85.9% for nonmated pairs. Repeatability and reproducibility were notably lower for comparisons assessed by the examiners as "difficult" than for "easy" or "moderate" comparisons, indicating that examiners' assessments of difficulty may be useful for quality assurance. No false positive errors were repeated (n = 4); 30% of false negative errors were repeated. One percent of latent value decisions were completely reversed (no value even for exclusion vs. of value for individualization). Most of the inter- and intra-examiner variability concerned whether the examiners considered the information available to be sufficient to reach a conclusion; this variability was concentrated on specific image pairs such that repeatability and reproducibility were very high on some comparisons and very low on others. Much of the variability appears to be due to making categorical decisions in borderline cases.     

Cerebral Blood Volume Analysis in Glioblastomas Using Dynamic Susceptibility Contrast-Enhanced Perfusion MRI: A Comparison of Manual and Semiautomatic Segmentation Methods

Purpose

To compare the reproducibilities of manual and semiautomatic segmentation method for the measurement of normalized cerebral blood volume (nCBV) using dynamic susceptibility contrast-enhanced (DSC) perfusion MR imaging in glioblastomas.

Materials and Methods

Twenty-two patients (11 male, 11 female; 27 tumors) with histologically confirmed glioblastoma (WHO grade IV) were examined with conventional MR imaging and DSC imaging at 3T before surgery or biopsy. Then nCBV (means and standard deviations) in each mass was measured using two DSC MR perfusion analysis methods including manual and semiautomatic segmentation method, in which contrast-enhanced (CE)-T1WI and T2WI were used as structural imaging. Intraobserver and interobserver reproducibility were assessed according to each perfusion analysis method or each structural imaging. Interclass correlation coefficient (ICC), Bland-Altman plot, and coefficient of variation (CV) were used to evaluate reproducibility.

Results

Intraobserver reproducibilities on CE-T1WI and T2WI were ICC of 0.74–0.89 and CV of 20.39–36.83% in manual segmentation method, and ICC of 0.95–0.99 and CV of 8.53–16.19% in semiautomatic segmentation method, repectively. Interobserver reproducibilites on CE-T1WI and T2WI were ICC of 0.86–0.94 and CV of 19.67–35.15% in manual segmentation method, and ICC of 0.74–1.0 and CV of 5.48–49.38% in semiautomatic segmentation method, respectively. Bland-Altman plots showed a good correlation with ICC or CV in each method. The semiautomatic segmentation method showed higher intraobserver and interobserver reproducibilities at CE-T1WI-based study than other methods.

Conclusion

The best reproducibility was found using the semiautomatic segmentation method based on CE-T1WI for structural imaging in the measurement of the nCBV of glioblastomas.     

Tactile spatial resolution measured manually: a validation study

The purpose of this study was to investigate the validity of manual application of the grating orientation task (GOT), as currently used in fundamental and clinical research. Six examiners tested 12 subjects following recommendations of the literature. The results show that the normal force applied with the domes on the skin varied from one examiner to the next. Nevertheless, it did not affect the performance of the subjects, whose thresholds were consistent with those reported in the literature. This study highlights the inter-examiner reliability in the manual application of this test and validates this procedure.     

Tactile spatial resolution measured manually: A validation study

The purpose of this study was to investigate the validity of manual application of the grating orientation task (GOT), as currently used in fundamental and clinical research. Six examiners tested 12 subjects following recommendations of the literature. The results show that the normal force applied with the domes on the skin varied from one examiner to the next. Nevertheless, it did not affect the performance of the subjects, whose thresholds were consistent with those reported in the literature. This study highlights the inter-examiner reliability in the manual application of this test and validates this procedure.     

Tridimensional dose evaluation of the respiratory motion influence on breast radiotherapy treatments using conformal radiotherapy,forward IMRT,and inverse IMRT planning techniques

PurposeTo evaluate the respiratory motion influence on the tridimensional (3D) dose delivery to breast-shaped phantoms using conformal radiotherapy (3D-RT), Field-in Field (FiF), and IMRT planning techniques.MethodsThis study used breast-shaped phantoms filled with MAGIC-f gel dosimeter to simulate the breast, and an oscillation platform to simulate the respiratory motion. The platform allowed motion in the anterior-posterior direction with oscillation amplitudes of 0.34 cm, 0.88 cm, and 1.22 cm. CT images of the static phantom were used for the 3D-RT, FiF, and IMRT treatment planning. Five phantoms were prepared and irradiated for each planning technique evaluated. Phantom 1 was irradiated static, phantoms 2–4 were irradiated moving with the three different motion amplitudes, and phantom 5 was used as a reference. The 3D dose distributions were obtained by relaxometry of magnetic resonance imaging, and the respiratory motion influence in the doses distribution was accessed by gamma evaluations (3%/3mm/15% threshold) comparing the measurements of the phantoms irradiated under movement with the static ones.ResultsThe mean gamma approvals for three oscillatory amplitudes were 96.44%, 93.23%, and 91.65%; 98.42%, 95.66%, and 94.31%; and 94.49%, 93.51%, and 86.62% respectively for 3D-RT, FiF and IMRT treatments. A gamma results profile per slice along the phantom showed that for FiF and IMRT irradiations, most of the failures occurred in the central region of the phantom.ConclusionsBy increasing the respiratory motion movement, the dose distribution variations for the three planning techniques were more pronounced, being the FiF technique variations the smallest one.     

Interobserver Reproducibility of Diffusion-Weighted MRI in Monitoring Tumor Response to Neoadjuvant Therapy in Esophageal Cancer

Objective

To investigate the reproducibility of diffusion-weighted magnetic resonance imaging (DW-MRI) in assessing tumor response early in the course of neoadjuvant chemoradiotherapy in patients with operable esophageal cancer.

Methods

Eleven male patients (mean age 54.8 years) with newly diagnosed esophageal cancer underwent DW-MRI before and 10 days after start of chemoradiotherapy. Reproducibility of apparent diffusion coefficient (ADC) measurements by manual (freehand) and semi-automated volumetric methods was assessed.

Results

Interobserver reproducibility for the assessment of mean tumor ADC by the manual measurement method was good, with an ICC of 0.69 (95% CI, 0.36 to 0.85; P = 0.001). Interobserver reproducibility for the assessment of mean tumor ADC by the semi-automated volumetric measurement method was very good, with an ICC of 0.96 (95% CI, 0.91 to 0.98; P<0.001).

Conclusion

Semi-automated volumetric ADC measurements have higher reproducibility than manual ADC measurements in assessing tumor response to chemoradiotherapy in patients with esophageal adenocarcinoma.     

Comparative Validity and Reproducibility Study of Various Landmark-Oriented Reference Planes in 3-Dimensional Computed Tomographic Analysis for Patients Receiving Orthognathic Surgery

BackgroundThree-dimensional computed tomographic imaging has become popular in clinical evaluation, treatment planning, surgical simulation, and outcome assessment for maxillofacial intervention. The purposes of this study were to investigate whether there is any correlation among landmark-based horizontal reference planes and to validate the reproducibility and reliability of landmark identification.ResultsA total of 30 patients with facial deformity and malocclusion—10 patients with facial symmetry, 10 patients with facial asymmetry, and 10 patients with cleft lip and palate—were recruited. Comparing the differences among the 5 reference planes showed no statistically significant difference among all patient groups. Regarding intraobserver reproducibility, the mean differences in the 3 coordinates varied from 0 to 0.35 mm, with correlation coefficients between 0.96 and 1.0, showing high correlation between repeated tests. Regarding interobserver reliability, the mean differences among the 3 coordinates varied from 0 to 0.47 mm, with correlation coefficients between 0.88 and 1.0, exhibiting high correlation between the different examiners.ConclusionsThe 5 horizontal reference planes were reliable and comparable for 3D craniomaxillofacial analysis. These reference planes were useful in standardizing the orientation of 3D skull models.     

Intersession reliability of a posturo-stabilometric test,using a force platform

Aim of the studyTo evaluate the intersession reliability of a posturo-stabilometric examination.MethodsSingle blind clinical trial conducted in two sessions over two weeks.44 healthy volunteers free from postural and temporomandibular disorders. All the subjects complied with the criteria for completing the study.All the subjects underwent two sessions of posturo-stabilometric examinations in different visual and mandibular conditions.Sway area, sway length and the coordinates of the center of pressure were evaluated and statistically analyzed using the Intraclass correlation coefficient (ICC).ResultsAll the posturo-stabilometric parameters seemed to have an excellent reproducibility with overall ICCs higher than 70% and good confidence intervals except for the sway area (ICC 0.422 with CI 0.283–0.560 with open eyes and ICC 0.554 with CI 0.424–0.683 with closed eyes).ConclusionsThe posturo-stabilometric examination carried out using a force platform has a good intrasession and intersession reliability, especially considering sway velocity, COP X and COP Y parameters. The force platform usefulness in analyzing static posture is confirmed in any medical field.     

A Simplified Method to Measure Choroidal Thickness Using Adaptive Compensation in Enhanced Depth Imaging Optical Coherence Tomography

Purpose

To evaluate a simplified method to measure choroidal thickness (CT) using commercially available enhanced depth imaging (EDI) spectral domain optical coherence tomography (SD-OCT).

Methods

We measured CT in 31 subjects without ocular diseases using Spectralis EDI SD-OCT. The choroid-scleral interface of the acquired images was first enhanced using a post-processing compensation algorithm. The enhanced images were then analysed using Photoshop. Two graders independently graded the images to assess inter-grader reliability. One grader re-graded the images after 2 weeks to determine intra-grader reliability. Statistical analysis was performed using intra-class correlation coefficient (ICC) and Bland-Altman plot analyses.

Results

Using adaptive compensation both the intra-grader reliability (ICC: 0.95 to 0.97) and inter-grader reliability (ICC: 0.93 to 0.97) were perfect for all five locations of CT. However, with the conventional technique of manual CT measurements using built-in callipers provided with the Heidelberg explorer software, the intra- (ICC: 0.87 to 0.94) and inter-grader reliability (ICC: 0.90 to 0.93) for all the measured locations is lower. Using adaptive compensation, the mean differences (95% limits of agreement) for intra- and inter-grader sub-foveal CT measurements were −1.3 (−3.33 to 30.8) µm and −1.2 (−36.6 to 34.2) µm, respectively.

Conclusions

The measurement of CT obtained from EDI SD-OCT using our simplified method was highly reliable and efficient. Our method is an easy and practical approach to improve the quality of choroidal images and the precision of CT measurement.     

Neurophysiological evaluation of healthy human anorectal sensation

Patients with functional gastrointestinal disorders often demonstrate abnormal visceral sensation. Currently, rectal sensation is assessed by manual balloon distension or barostat. However, neither test is adaptable for use in the neurophysiological characterization of visceral afferent pathways by sensory evoked potentials. The aim of this study was to assess the reproducibility and quality of sensation evoked by electrical stimulation (ES) and rapid balloon distension (RBD) in the anorectum and to apply the optimum stimulus to examine the visceral afferent pathway with rectal evoked potentials. Healthy subjects (n = 8, median age 33 yr) were studied on three separate occasions. Variability, tolerance, and stimulus characteristics were assessed with each technique. Overall ES consistently invoked pain and was chosen for measuring rectal evoked potential whereas RBD in all cases induced the strong urge to defecate. Rectal intraclass correlation coefficient (ICC) for ES and RBD (0.82 and 0.72, respectively) demonstrated good reproducibility at pain/maximum tolerated volume but not at sensory threshold. Only sphincter ICC for ES at pain showed acceptable between-study reproducibility (ICC 0.79). Within studies ICC was good (>0.6) for anorectal ES and RBD at both levels of sensation. All subjects reported significantly more unpleasantness during RBD than ES (P < 0.01). This study demonstrates that ES and RBD are similarly reproducible. However, the sensations experienced with each technique differed markedly, probably reflecting differences in peripheral and/or central processing of the sensory input. This is of relevance in interpreting findings of neuroimaging studies of anorectal sensation and may provide insight into the physiological characteristics of visceral afferent pathways in health and disease.     

Reliability of medial-longitudinal-arch measures for skin-markers based kinematic analysis

The medial-longitudinal arch (MLA) is perhaps the most important feature characterizing foot morphology. While current skin-markers based models of the MLA angle used in stereophotogrammetry allow to estimate foot arch shape and deformation, these do not always appear consistent with foot anatomy and with standard clinical definitions. The aim of this study was to propose novel skin-markers based measures of MLA angle and investigate their reliability during common motor tasks.Markers on the calcaneus, navicular tuberosity, first metatarsal head and base, and on the two malleoli were exploited to test eight definitions of MLA angle consistent with foot anatomy, both as angles between two 3-dimensional vectors and as corresponding projections on the sagittal plane of the foot. The inter-trial, inter-session and inter-examiner reliability of each definition was assessed in multiple walking and running trials of two volunteers, tested by four examiners in three sessions.Inter-trial variability in walking was in the range 0.7–1.2 deg, the inter-session 2.8–7.5 deg, and the inter-examiner in the range 3.7–9.3 deg across all MLA definitions. The Rizzoli Foot Model definition showed the lowest inter-session and inter-examiner variability. MLA measures presented similar variability in walking and running.This study provides preliminary information on the reliability of MLA measurements based on skin-markers. According to the present study, angles between 3-dimensional vectors and minimal marker sets should be preferred over sagittal-plane projections. Further studies should be sought to investigate which definition is more accurate with respect to the real MLA deformation in different loading conditions.     

Reproducibility of Middle Cerebral Artery Stenosis Measurements by DSA: Comparison of the NASCET and WASID Methods

Purpose

To evaluate the intra- and inter-observer variability of the North American Symptomatic Carotid Endarterectomy Trial (NASCET) and Warfarin-Aspirin Symptomatic Intracranial Disease (WASID) criteria for the evaluation of middle cerebral artery (MCA) stenosis using digital subtraction angiography (DSA).

Materials and Methods

DSA images of 114 cases with 131 stenotic MCAs were retrospectively analyzed. Two radiologists and a researcher measured the degree of MCA stenosis independently using both NASCET and WASID methods. To determine intra-observer agreement, all the observers reevaluated the degree of MCA stenosis 4 weeks later. The linear relation and coefficient of variation (CV) between the measurements made by the two methods were assessed by correlation coefficient and multi-factor analysis of variance (ANOVA), respectively. Intra- and inter-observer variability of the two methods was evaluated by intraclass correlation coefficient (ICC), Spearman’s R value, Pearson correlation coefficient and Bland-Altman plots.

Results

Despite the fact that the degree of MCA stenosis measured by NASCET was lower than measured using the WASID method, there was good linear correlation between the measurements made by the two methods (for the mean measurements of the 3 observers, NASCET% = 0.891 × WASID% - 1.89%; ICC, Spearman’s R value and Pearson correlation were 0.874, 0.855, and 0.874, respectively). The CVs of both intra- and inter-observer measurements of MCA stenosis using WASID were significantly lower than that using NASCET confirmed by the multi-factor ANOVA results, which showed only the measurement methods of MCA stenosis had significant effects on the CVs both in intra- and inter-observer measurements (both P values < 0.001). Intra-observer measurements showed good or excellent agreement with respect to WASID and NASCET evaluation (ICC, 0.656 to 0.817 and 0.635 to 0.761, respectively). Good agreement for the WASID evaluation (ICC, 0.592 to 0.628) and for the NASCET evaluation (ICC, 0.529 to 0.568) was observed for inter-observer measurements. Bland-Altman plots demonstrated that the WASID method had better reproducibility and intra-observer agreement than NASCET method for evaluating MCA stenosis.

Conclusion

Both NASCET and WASID methods have an acceptable level of agreement; however, the WASID method had better reproducibility for the evaluation of MCA stenosis, and thus the WASID method may serve as a standard for measuring the degree of MCA stenosis.     

Examiner agreement on caries detection and plaque accumulation during dental surveys of elders

Indices used to evaluate plaque accumulation and coronal caries have been widely accepted in epidemiological studies, yet their reliability cannot be guaranteed. The aim of this study was to evaluate the reliability of clinical criteria used in coronal and root caries diagnosis and oral hygiene evaluation as applied in elders. Nineteen elderly subjects, 73 years old on average, were examined at a first appointment by two independent examiners. They were re-examined two weeks later. Plaque accumulation was evaluated using the Plaque Index (PI) and coronal and root caries were detected according to the WHO criteria and Fejerskov et al (1991), respectively. Recurrent caries was recorded as recommended by WHO and by probing at the interface tooth-restoration. Inter- and intra-examiner agreement was evaluated using kappa statistics. The PI score showed good reliability except for examiner b, for whom a simplification of the 4-point scale in 3-point scale improved significantly the reliability. The prevalence of coronal caries was very low and intra- and inter-examiner agreement was poor. Most of the root caries lesions were covered by plaque and the kappa values indicated only poor agreement. Recurrent caries were found with good agreement using WHO criteria but the detection with the probe was not reliable. In conclusion, it seems that examiners should be trained carefully to maximise their reliability and that plaque should be removed to obtain reliable diagnoses of caries. Retraining and calibration may be necessary for surveys continuing over a long period.