The abilities of Parkinson's disease (PD) patients, taking routine medication, and of control subjects, to discriminate bilateral differences in the static angular positions of the two elbow joints were studied during passive (subject relaxed) and active (subject contracting to hold position) conditions. On each trial, one of the subject's elbows served as the reference joint (angle 60°) and the other as the test joint (angular range, 54° to 69°, at 3° intervals). Subjects, with eyes closed, were required to discriminate the relative angles of the two elbows. In Experiments 1 (passive condition) and 2 (active condition), parkinsonians (n = 12) gave significantly fewer correct responses, pooled across sides, than did controls (n = 12), both in total scores across all angles and at individual test angles of 57° and 63°. In Experiment 3 (passive condition), derivation of conventional psychophysical variables indicated that both the difference limen (DL; threshold) and Weber ratio (WR; discriminatory sensitivity, independent of absolute stimulus values; same as DL/PSE) values of patients (n = 6) were significantly larger than those of controls (n = 6), in the absence of a significant difference between groups in the point of subjective equality (PSE). Our results provide clear evidence of a quantitative impairment of joint position sense in PD patients. Ann Neurol 2000;47:218–228

We have compared the ability of patients with idiopathic Parkinson's disease (PD) with that of control subjects to identify unilateral elbow-joint position, in the absence of direct vision of the arm, by visual reference to a graduated angular scale, placed beside the elbow, across a range of test angles of 90-108 degrees. The positioning of the subject's elbow was achieved under either passive (subject relaxed, Experiment 1) or active (subject contracting, Experiment 2) conditions. PD patients' performance (while on L-dopa medication) with the elbows on the sides of "worse" and "better" motor signs was compared with that of controls with, respectively, the left and right elbows. In both experiments, (a) both the individual, overall mean unsigned (with respect to direction) error averaged across all test angles (accuracy), and the SD about this mean (precision), were significantly larger on each side among PD patients than among controls, and (b) the subjective ranges of values employed by PD patients were substantially compressed, on average, by comparison with those of controls. Within-group analyses revealed that (a) among control subjects, but not among PD subjects, individual, overall mean unsigned errors, on each side, averaged across test angles, were significantly smaller under active than under passive conditions, and (b) the subjective ranges employed by PD patients, but not by controls, under active conditions significantly exceeded those under passive conditions. We conclude that these results are generally consistent with the notion that PD impairs unilateral elbow-joint position sense.

We have compared the abilities of patients with idiopathic Parkinson's disease (PD), while on levodopa (L-dopa), and control subjects to discriminate bilateral differences in the loci of tactile stimulation. On each trial, one of a subject's forearms served as the reference arm and the other as the test arm. The two forearms were supinated and placed side-by-side on a table-top in front of the subject. Seven cutaneous test loci, 3 mm apart, were arrayed proximo-distally on the flexor aspect of each forearm, with the fourth (central) serving as a reference point. On each trial, two punctate tactile stimuli (of intensity well above perceptual threshold) were applied simultaneously to 1) one of the seven test loci on the test forearm and 2) the reference (central) locus on the reference arm. Subjects, with eyes closed, stated which forearm (test or reference) was stimulated more distally. Estimates of the difference limen (DL, a measure of discriminatory threshold) and the point of subjective equality (PSE, the test locus perceived to correspond to the reference locus) were derived from psychophysical functions (ogives). For each subject, one arm was defined as 'better' and the other as 'worse.' Among PD patients, this definition was in terms of the relative severity of clinical motor signs (combined scores for bradykinesia, rigidity and tremor) of the two arms, whereas among controls it was according to relative DL magnitudes (sensory/perceptual performance). The mean DL of the patients significantly exceeded that of control subjects on both the 'better' and 'worse' arms as test side, but mean PSE values did not differ significantly between groups. Thus, our PD patients were impaired in discriminating bilateral differences in the locations of tactile stimulation, while perceiving normally the relative locations of the proximo-distal centers of the two stimulus arrays.

The abilities of Parkinson's disease (PD) patients, taking routine medication, and of control subjects, to discriminate bilateral differences in the static angular positions of the two elbow joints were studied during passive (subject relaxed) and active (subject contracting to hold position) conditions. On each trial, one of the subject's elbows served as the reference joint (angle 60 degrees) and the other as the test joint (angular range, 54 degrees to 69 degrees, at 3 degree intervals). Subjects, with eyes closed, were required to discriminate the relative angles of the two elbows. In Experiments 1 (passive condition) and 2 (active condition), parkinsonians (n = 12) gave significantly fewer correct responses, pooled across sides, than did controls (n = 12), both in total scores across all angles and at individual test angles of 57 degrees and 63 degrees. In Experiment 3 (passive condition), derivation of conventional psychophysical variables indicated that both the difference limen (DL; threshold) and Weber ratio (WR; discriminatory sensitivity, independent of absolute stimulus values; same as DL/PSE) values of patients (n = 6) were significantly larger than those of controls (n = 6), in the absence of a significant difference between groups in the point of subjective equality (PSE). Our results provide clear evidence of a quantitative impairment of joint position sense in PD patients.

We describe the use of a new molecular assay for Trichomonas vaginalis (TV), the Gen-Probe Aptima TV (ATV) in female attendees at community clinics, a genitourinary (GU) medicine clinic and a prison GU medicine service. Positivity rates at community clinics and GU medicine were 0/382 (0%) and 3/358 (0.8%, 95% confidence interval [CI] 0-1.7%), respectively. Positivity was significantly higher, 29/269 (10.8%, 95% CI 7.1-14.5%), odds ratio (OR) 14.3 (4.11 < OR < 59.55), in those tested at the prison. A questionnaire survey of English GU medicine clinics and data from the UK Health Protection Agency (HPA) for England both demonstrated the large variation in case rates by region and testing methods employed. Higher rates were seen in women, in prison GU medicine services and in London GU medicine clinics. The ATV assay is now CE-marked (Conformité Européenne) and so a larger prospective study of its potential application is warranted.