RPD Group Research Articles

The optimal choice for patients underwent minimally invasive pancreaticoduodenectomy: a systematic review and meta-analysis including patient subgroups.

We searched PubMed, Embase, Web of Science, and the Cochrane Library database systems for studies that compared RPD with laparoscopic pancreaticoduodenectomy (LPD). Meta-analysis was performed for 24 relevant outcomes, including perioperative outcomes and postoperative complications. Subsequently, a subgroup analysis based on geographical regions was conducted to investigate the impact of regional differences on the perioperative outcomes of the RPD group and the LPD group. This review found 19 studies with 12,731 individuals (3539 RPD and 9192 LPD). In comparison to LPD, RPD had lower rates of Conversion (OR = 0.58, P < 0.00001), Blood Transfusion (OR = 0.59, P = 0.02), Length of Stay (MD = - 0.54, P = 0.01), postoperative complications [Pneumonia (OR = 0.31, P < 0.0001), and Wound Disruption (OR = 0.26, P = 0.0007)], and more thorough lymph node harvesting (MD = 1.25, P = 0.001). Subgroup analysis showed that Blood Transfusion (I2 = 55%, P = 0.02), Conversion (I2 = 30%, P < 0.00001), Length of Stay (I2 = 71%, P = 0.01), and Lymph Node Harvested (I2 = 87%, P = 0.001) were statistically significant. Interestingly, compared to China, other countries had lower rates of Conversion and more lymph nodes harvested for RPD surgery. The benefits of RPD surgery over LPD surgery in terms of therapy and an optimistic short-term prognosis are clearly supported by this study. Moreover, subgroup analysis based on regional differences revealed statistically significant results for Conversion, Length of Stay (days), Number of Lymph Nodes Harvested and the rate of Blood Transfusion, indicating significant variability across regions. This study provides a solid theoretical foundation and basis for the advancement of RPD in clinical practice.

The vastus medialis oblique compensates in current patellar dislocation patients with the increased femoral anteversion

PurposeThe purpose of this study was to investigate whether the vastus medialis oblique (VMO) muscle compensates in patellar dislocation (PD) patients with the increased femoral anteversion angle (FAA).MethodsBetween 2021 and 2024, we included 60 patients with recurrent PD (RPD group). Inclusion criteria were at least two episodes of PD, as well as complete CT scans of the knee and hip. Exclusion criteria included traumatic or habitual dislocation, previous knee surgery, etc. Of these patients, 30 with excessive FAA (≥ 30°) were assigned to the A group, and 30 without excessive FAA (< 30°) to the B group. A control group of 120 patients without patellofemoral disorders was also included (C group). The cross-sectional areas of the VMO and vastus lateralis muscle (VLM) were measured 20 mm above the patella on CT scans, and the VMO/VLM area ratio was calculated. The correlation between FAA and the VMO/VLM ratio was analyzed.ResultsThe RPD group had a significantly larger FAA (15.0 ± 1.9° vs. 30.1 ± 9.6°, P = 0.040) and a smaller VMO/VLM ratio (4.2 ± 1.5 vs. 3.5 ± 1.0, P = 0.014) compared to the C group. Within the RPD group, the A group had a higher VMO/VLM ratio than the B group (4.0 ± 1.1 vs. 3.0 ± 0.7, P = 0.029). The B group’s VMO/VLM ratio was lower than that of the C group (3.0 ± 0.7 vs. 4.2 ± 1.5, P = 0.004). However, there was no significant difference in the VMO/VLM ratio between the A group and the C group. The VMO/VLM ratio showed a moderate positive correlation with FAA in the RPD group, with a correlation coefficient of r = 0.4 (P = 0.012), indicating a statistically significant relationship between the two.ConclusionPatients with recurrent PD showed a smaller VMO/VLM ratio compared to controls. Increased FAA was correlated with compensatory thickening of the VMO and a higher VMO/VLM ratio in PD patients. This suggests that increased FAA may drive biomechanical adaptations in the quadriceps, stabilizing the patella. Clinicians should consider changes in FAA when assessing and treating PD.Level of evidenceLevel III.

Effects of various prosthetic methods for patients with Kennedy Class I partial edentulism on oral hypofunction, subjective symptoms, and oral health-related quality of life

PurposeThis propensity score matching, multicenter, cross-sectional study was performed to examine the effects of various prosthetic methods for dental clinic outpatients with Kennedy Class I partial edentulism (KCIPE) on oral hypofunction, subjective frailty symptoms, and oral health-related quality of life (QOL).MethodsPatients (n = 348) were classified into the following three groups for analysis: NT, patients with natural dentition providing intermaxillary contact in four occlusal supporting zones; RPD, patients with KCIPE who received removable partial dentures; and ISFP, patients with KCIPE who received implant-supported fixed prostheses. Participants' basic characteristics were recorded, and oral function tests were conducted. Subjective symptoms of physical and oral frailty were investigated via questionnaire. Oral health-related QOL was assessed using the Japanese short version of the Oral Health Impact Profile (OHIP-JP16). Propensity score matching was performed to adjust for patient background factors that could influence oral hypofunction in each group.ResultsCompared with the ISFP group, the RPD group had significantly higher rates of poor oral hygiene, reduced occlusal force, decreased masticatory function, and declines in swallowing function and oral hypofunction; the odds ratio for oral hypofunction was 4.67. Compared with the ISFP group, the RPD group had significantly greater subjective symptoms of physical frailty and oral frailty, as well as higher OHIP scores.ConclusionsProsthetic treatment of KCIPE affected oral hypofunction, subjective frailty symptoms, and oral health-related QOL in dental clinic outpatients.

Radiographic Progression at Castration-Resistant Prostate Cancer Diagnosis: A Prognostic Indicator of Metastatic Hormone-Sensitive Prostate Cancer

BackgroundThe critical role of radiographic assessment at the time of castration-resistant prostate cancer (CRPC) diagnosis is underscored by this study. We performed a retrospective analysis of radiographic changes in metastasis from the time of diagnosis of metastatic hormone-sensitive prostate cancer (mHSPC) to CRPC diagnosis. We also explored its impact on prognosis post-CRPC. Materials and MethodsWe retrospectively analyzed 98 men who underwent radiographic examinations (bone scans and computed tomography [CT]) at the time of CRPC diagnosis. When radiographic studies demonstrated progression at CRPC diagnosis, patients were assigned to the radiographic progressive disease (rPD) group. The remaining patients were placed in the "non-rPD" group. The overall survival (OS) post-CRPC was compared between the 2 groups. ResultsThe median OS post-CRPC was significantly shorter in the rPD group (n = 50) compared to the non-rPD group (n = 48) (32 months vs. not reached, P = .0124). Multivariate analysis showed that radiographic progression and shorter time to CRPC were associated with a shorter OS post-CRPC (hazard ratio [HR] = 3.14; 95% confidence interval [CI], 1.21-8.12, P = .019). ConclusionRadiographic progression at the point of CRPC diagnosis independently predicts a shorter OS post-CRPC in patients with mHSPC. Therefore, assessing radiographic changes at the time of CRPC diagnosis could be instrumental in managing CRPC in patients with mHSPC.

Effects of rhubarb peony decoction combined with antibiotics in treating pediatric periappendiceal abscess.

Rhubarb peony decoction (RPD) is a formula of traditional Chinese medicine that has been widely used to treat intra-abdominal inflammatory diseases. To investigate the therapeutic efficacy of RPD in pediatric periappendiceal abscess, patients who received intravenous antibiotics alone were compared with those treated with intravenous antibiotics combined with RPD. A retrospective review of children with periappendiceal abscess who received conservative treatment in our hospital between January 2013 and April 2022 was performed. The patients were divided into an intravenous antibiotic group (the control group) and an intravenous antibiotic combined with RPD group (the intervention group). Interval appendectomy (IA) was generally performed 10-12 weeks after conservative treatment. The primary outcome was the cure rate of conservative treatment, while the secondary outcomes included the recurrence rate, days of total intravenous antibiotic use, length of hospital stay (LOS), postoperative complications, and liver injury caused by RPD. A total of 142 patients (77 girls and 65 boys) were included, 52 in the control group and 90 in the intervention group. The two groups were similar in demographic data and clinical characteristics (P > 0.05). The mean total course of RPD in the intervention group was 11.82 days. The intervention group had a significantly higher cure rate than the control group (93.33% vs. 80.77%, P = 0.029), and the length of total intravenous antibiotic use (P = 0.150), LOS (P = 0.077), recurrence rate (9.52% vs. 4.76%, P = 0.439), as well as the operation time (P = 0.101), LOS (P = 0.572), and postoperative complications (P = 0.549) were not significantly different between the two groups when the patients received IA. No patient had a liver injury caused by RPD during the treatment. Intravenous antibiotics combined with RPD demonstrated high effectiveness and safety for treating pediatric periappendiceal abscess.

Robotic-assisted pancreaticoduodenectomy with vascular resection. Description of the surgical technique and analysis of early outcomes

BackgroundDespite the potential benefits, the adoption of the minimally invasive surgery for the treatment of borderline resectable pancreatic cancer is still in the initial phase. We investigated the safety and feasibility of the robotic pancreaticoduodenectomy with venous resection/reconstruction (RPD SMV/PV). MethodsSince March 2013 to October 2019, a total of 73 RPD and 10 RPD SMV/PV were performed. The two groups were case-matched according to the preoperative characteristics. ResultsMean operative times and estimated blood loss were less in the RPD group in comparison to that in the RPD with SMV-PV group (525 vs 642 min, p = 0.003 and 290 vs 620 ml, p = 0.002, respectively). The mean length of hospital stay was similar in the RPD group in comparison to that in the RPD with SMV-PV group (10 days vs 13 days, p = 0.313). The two groups had similar overall postoperative morbidity rate (57.5% vs 60%, p = 0.686), although the severe complication rate was lower in the RPD group (11% vs 40%, p = 0.004). ConclusionsRPD with SMV-PV is associated with increased operative time, estimated blood loss, higher major complication rate compared with RPD.

Comparison of Robot and open pancreaticodenectomy for the treatment primary duodenal adenocarcinoma

Introduction: Robot surgery is a new method that maintains advantages and overcomes disadvantages of conventional methods, a surgical option for primary duodenal adenocarcinoma (PDA), is a complex procedure that has become increasing popular. However, there is no consensus as to whether this technique should be performed routinely. Our aim was to evaluate the outcomes of RPD compared with open pancreaticoduodenectomy (OPD). Method: Retrospective analysis of all pancreaticoduodenectomies at a single quaternary cancer referral center was performed, From January 2013 to March 2018, 50 RPDs were performed to treat PDA and were compared with 43 OPDs. Patients were also matched based on their demographic data and pathologic diagnosis. Demographic information, intraoperative and postoperative data, pathologic data, and follow-up evaluation data were collected at our center. And then compared using standard statistical methods. Result: The average follow-up time of all patients was 26.86 months (range 1.67 to 70.80 months). There were no significant differences in demography, short-term complications, pathological results or TNM staging between the two groups. The survival time of RPD group was slightly longer than that of OPD group (P=0.036). There were significant differences in oral time, blood loss time and hospital stay between the two groups (P < 0.05). However, there were no differences between the robotic group and the open group in terms of operation time, pancreatic texture, pancreatic anastomosis, vascular reconstruction, reoperation, 30-day readmission, chemotherapy, recurrence or R0 resection. Conclusion: This study found that RPD is a feasible, safe, and effective method for the treatment of PDA compared with OPD , may be a better preferred method for surgeons to choose for he treatment of PDA.

ORAL HEALTH

Objective: To compare the percentage decrease in score of Oral healthrelated quality of life in patients provided with removable and fixed partial dentures. Evaluationof Prosthodontic treatment is made on the basis of clinical observations or from the patientsatisfaction1.tooth loss deteriorates the psychological, functional and social status of anindividual. OHRQoL has been considered as a tool for measurement of consequences of toothloss and available treatment options. Quality of life is influenced by use of removable partialdentures or fixed partial dentures which may also deteriorate oral functions. Setting: Departmentof Prosthodontic, de’Montmorency College of Dentistry/Punjab Dental Hospital, Lahore. StudyDesign: Randomized Controlled Trial. Period: 07th May 2011 to 07th November 2011. Method:Total 60 partially dentate subjects with two teeth missing in either dental arch recruited fromOPD of department of Prosthodontic, de’Montmorency College of Dentistry/Punjab DentalHospital, Lahore. They were divided equally into two groups (Group 1=30 subjects for RPR,Group 2=30 subjects for FPD). All the subjects were given OHIP-14 questionnaire to measurethe OHRQoL before treatment and one month after the provision of prosthesis. Before and aftertreatment scores were recorded on 5 points Lickert scale and coded as +0=never,1=hardlyever,3=occasionally,4=fairly often,5=very often. The scores on Lickert scale were inverselyproportional to the improvement in OHRQoL. Results: Subject with FPD group showed markeddecrease in percentage of OHRQoL after the provision of prosthesis. In comparison with FPDpercentage decrease in OHRQoL was less pronounced in RPD group. There was 62.84%reduction in OHRQoL score who were randomized in removable partial dentures while 90.53%reduction was observed in OHRQoL score who were randomized in fixed partial dentures. Thisshowed that fixed partial dentures are more effective in improving quality of life of patients withpartial dentations. Conclusion: Subjects with FPD showed marked decrease in percentageof OHRQoL; suggest that FPD influenced their social, psychological and functional status in amore positive way as compared to the subjects provided with RPD.

Shortened dental arch concept shown to be cost effective

Randomised controlled trial. All patients received treatment to render them dentally fit. Patients were randomly allocated to either the removable dental prostheses (RPD) or the shortened dental arch (SDA) group. Patients in the RDP group were restored to complete arches with RDP using cobalt-chromium frameworks according to a standardised protocol. For the SDA group, patients were restored to a shortened arch of ten occluding pairs of natural and replacement teeth using resin-bonded bridgework (RBB). Treatment effect was measured using the change in oral health-related quality of life (OHrQOL). For each patient the costs of delivering treatment were recorded by a research nurse during the intervention period. Laboratory costs were recorded as part of normal hospital policy for all patients. All of the dental materials used were recorded and given a unit price. The cost of professional time per patient was estimated using the highest point of the salary scale for the Community Dental Service in Ireland. One hundred and thirty-two patients were randomised; 65 to the RPD group and 67 to the SDA group. Ninety-two patients (69.7%) completed the study (46 in RPD group; 46in SDA group). There was no difference in the success rates of the two treatments over the period. Five pieces of resin-bonded bridgework (RBB) debonded and were recemented over the 12-month period giving a success rate of 95.5% for the RBB. Four patients discontinued wearing their RPDs; all four RPDS were fitted in the lower arch and included bilateral free end saddles, a success rate of 95.9%. Both RPD and SDA groups demonstrated statistically significant improvements in OHrQoL scores after 12 months.The total cost of achieving the minimally important clinical difference (MID) in OHrQOL for an average patient in the RDP group was [euro ]464.64. For the SDA group, the cost of achieving the MID for an average patient was [euro ]252.00. The cost-effectiveness ratio was therefore 1:1.84 in favour of SDA treatment. With an increasingly ageing population, many patients will continue to benefit from removable prostheses to replace their missing natural teeth. From a purely economic standpoint, the results from this analysis suggest that the treatment of partially dentate older adults should be focused on functionally orientated treatment because it is simply more cost-effective.

Topographic pattern of cortical thinning with consideration of motor laterality in Parkinson disease.

The asymmetry of Parkinson's disease (PD) may contribute to the unilateral appearance of parkinsonism, as well as its cerebral morphological changes. However, previous studies have not considered that cerebral involvement would probably be asymmetric. Our study aimed to identify whether one-sided symptom dominance has an influence on cortical thinning patterns in early-stage, non-demented PD patients from cortical thickness analyses and cortical thinning patterns are associated with motor functions. We used cortical thickness analysis in 64 non-demented right-handed subjects: 21 PD patients with left-sided disease onset (LPD), 21 PD patients with right-sided disease onset (RPD) and 22 control subjects. We modeled local cortical thickness as a linear association with each motor symptom. We identified three clusters exhibiting significant cortical thinning (p<0.01 RFT corrected) in the LPD group compared with the control group: a cluster including the right primary sensory, motor cortex and paracentral lobule, as well as another two clusters in bilateral parahippocampal gyri. In the RPD group, there was only one cluster that exhibited significant cortical thinning compared with the control group, located in the left lingual gyrus. There were no significant correlations between cortical thinning clusters and motor severity, any of the motor subscales including tremor, rigidity, bradykinesia and axial impairment. Our right-handed PD population revealed that significant thinning of motor-related cortical areas in contralateral hemisphere to symptomatic side in LPD, but not in RPD group. Our results support that neuroprotective effect of enhanced physical activity by handedness on contralateral motor cortex.

Interhemispheric functional connectivity changes in early Parkinson disease with the symptom asymmetry

Objective To investigate changes of the interhemispheric coordination integrity in patients with hemi-parkinsonism using resting-state functional magnetic resonance imaging(rs-fMRI) homotopy technique called voxel-mirrored homotopic connectivity(VMHC).Methods Sixteen Parkinson disease(PD) patients with right body side motor symptom onset(RPD),15 patients with left side onset(LPD),and 19 age-,gender-,and education-matched healthy controls(HC) were included in this study.rs-fMRI scanning and pre-processed the raw data were performed.Then by using analysis of variance(ANOVA) and two sample t tset,we performed VMHC analyses on rs-fMRI data of these participants(P＜0.05,corrected with AlphaSim,clusters≥16 voxels).Exploratory linear correlations analyses were performed between the VMHC of regions showing significant group differences and the clinical features of LPD or RPD patients.Results Compared with HCs,patients with LPD had significantly reduced VMHC in visual regions,sensorimotor regions,and the cerebellar cortex(voxels size of 17-77,t=-5.06--3.42,P＜0.05).Patients with RPD exhibited decreased VMHC in the prefrontal cortex and sensorimotor regions.Both LPD and RPD groups had increased VMHC in subcortical regions.When compared with the RPD group,the LPD group displayed decreased VMHC in the visual regions,sensorimotor regions(voxels=16 and 18; t=-3.68and-3.87,respectively,both P＜0.05) and increased VMHC in the supramarginal gyrus(voxels=4,t=4.72,P＜0.05);ROI-based correlation analyses indicated that the VMHC in the inferior occipital gyrus and the postcentral gyrus was negatively correlated with the BDI-Ⅱ scores in the LPD group(r=-0.58 and-0.59,respectively; both P＜0.05),and positively correlated with the MMSE scores(r=0.56 and 0.52,respectively;both P＜0.05).In the RPD group,a positive correlation was found for the VMHC in the supramarginal gyrus and the illness duration(r=0.56,P＜0.05) and for the VMHC in the postcentral gyrus and the(mini-mental state exam) MMSE(r=0.53,P＜0.05).Conclusions The differential pattern of deficits in the interhemispheric coordination integrity in hemi-parkinsonism reflected by VMHC may provide insights into the neurological pathophysiology underlying the asymmetry of symptom appearance in PD. Key words: Parkinson disease; Magnetic resonance imaging; Neural networks(computer)

CLINICAL STUDY OF THE EFFECTS OF LOW-PROTEIN DIET AND SUPPLEMENTED WITH α-KETOACIDS THERAPY ON NUTRITION STATUS AND RESIDUAL RENAL FUNCTION IN CONTINUOUS AMBULATORY PERITONEAL DIALYSIS(CAPD) PATIENTS

It is critical to preserve residual renal function (RRF) in CAPD, as RRF is associated with lower morbidity and mortality. low- protein diet supplemented with α-keto acids was reported to have an important roles in delaying in follow-up period progression of renal failure and relieving malnutritional status in non-dialysis patients with chronic renal failure. We evaluate the effects on the nutritional status and RRF of a low-protein diet supplemented with α-keto acids on CAPD patients prospectively. Seventy eight CAPD patients who were randomly assigned to a low-protein diet supplemented with α-keto acid group(keto acid group,31 patients),low-protein diet group(LPD group,26 patients)and routine protein diet group(RPD group,21 patients)were investigated and followed up for one year. The nutritional parameters were measured, and examinations of residual renal function (RRF), Kt/v, clearance of creatinine (Ccr) and levels of serum amino acids, mean arterial pressure (MAP), peritoneal ultrafiltration(UF),residual urine volume(RUV) and the status of water-sodium retentio were performed. Compared to LPD group, serum levels of prealbumin(PA), transferrin (TRF) retinal binding protein (RBP) had a significant increment both in keto acid group and RPD group(P〈0.01),but there was no significance between these two groups(p〉0.05)□Compared to RPD group, There was an incremental tendency in albumin(Alb), total cholesterol(TC), triglyceride (TG), Triceps skinfoles (TSF),midarm riuscle circumference(MAMC),body mass index(BMI) in keto acid group, but no significance(p〉0.05)□The serum concentrations of Valine(Val),Leucine(Leu), Isoleucine (Ile) were significantly increased in keto acid group(p〈0.01),compared to the other groups. Levels of RRF, Kt/V, Ccr, RUV were significantly higher both in keto acid group and LPD group than in RPD group(p〈0.01)□There were no significant differences in MAP, UF and peritoneal dialysate albumin loss between these groups, However, the trend of peritoneal dialysate albumin loss in keto acid group and LPD group was descendent□ Proteinuria decreased most significantly in keto acid group (P〈0.01).In conclusion, Low-protein diet supplemented with α-keto acids therapy has a tendency of protecting RRF in CAPD patients while relieving malnutritional status and improving the 1evels of branched chain amino acids.

Mood, side of motor symptom onset and pain complaints in Parkinson's disease

Patients with Parkinson's disease (PD) present with a variety of non-motor symptoms including sensory complaints and mood disturbances. In the current pilot study, we aimed to explore pain complaints and the association between mood and pain in PD. We hypothesized that pain ratings would be elevated in patients with PD relative to controls. As PD is lateralized at onset and studies have found lateralization of some non-motor symptoms in PD, we also hypothesized that PD patients would exhibit differing pain profiles depending on side of onset of the disease. Twenty-three PD patients (11 right-onset (RPD), 12 left-onset (LPD) disease), and 11 control participants (CS) completed a mood questionnaire (Depression Anxiety Stress Scale; DASS) as well as the short form of the McGill Pain Questionnaire. Both PD groups reported higher present pain intensity scores (p = 0.001), more evaluative pain intensity (p = 0.02), and more overall pain (p = 0.02) than control participants. There was a significant association between mood and all of the McGill pain ratings in the LPD patients, with those reporting more mood symptoms rating higher on all pain scales (all p-values < 0.001). This association was not found in the RPD group. Our results suggest an association between mood and pain in patients with PD that may be related to the differential contribution of right-hemispheric neural networks in processing of mood and pain states. These findings merit further investigation into the relation between mood and pain in patients with PD.

Comparisons between a mixing ability test and masticatory performance tests using a brittle or an elastic test food

A variety of chewing tests and test items have been utilized to evaluate masticatory function. The purpose of this study was to compare a mixing ability test with masticatory performance tests using peanuts or gummy jelly as test foods. Thirty-two completely dentate subjects (Dentate group, mean age: 25.1 years) and 40 removable partial denture wearers (RPD group, mean age: 65.5 years) participated in this study. The subjects were asked to chew a two-coloured paraffin wax cube as a test item for 10 strokes. Mixing Ability Index (MAI) was determined from the colour mixture and shape of the chewed cube. Subjects were asked to chew 3 g portions of peanuts and a piece of gummy jelly for 20 strokes, respectively. Median particle size of chewed peanuts was determined using a multiple-sieving method. Concentration of dissolved glucose from the surface of the chewed gummy jelly was measured using a blood glucose meter. Pearson's correlation coefficient was used to test the relationships between the MAI, median particle size and the concentration of dissolved glucose. Mixing Ability Index was significantly related to median particle size (Dentate group: r = -0.56, P < 0.001, RPD group: r = -0.70, P < 0.001), but not significantly related to glucose concentration (Dentate group: r = 0.12, RPD group: r = 0.21, P > 0.05). It seems that ability of mixing the bolus is more strongly related to the ability of comminuting brittle food than elastic food.

Body side of motor symptom onset in Parkinson's disease is associated with memory performance

The relation of body side of motor symptom onset in Parkinson's disease (PD) to memory measures associated with hemispheric dominance was examined. Fourteen patients with right body side motor symptom onset (RPD, inferred left hemisphere dysfunction) and 16 patients with left side onset (LPD, right hemisphere dysfunction) were administered measures of verbal (Hopkins Verbal Learning Test-Revised) and visual memory (Brief Visual Memory Test-Revised), that require similar task demands and are associated with left or right hemisphere dominance, respectively. The LPD group demonstrated poorer visual than verbal memory, both within group and in comparison to the RPD group. By contrast, the RPD group showed poorer verbal than visual memory within group. These findings suggest that side of motor symptom onset is associated with asymmetrical memory dysfunction.

Hemispace differences in the visual perception of size in left hemiParkinson’s disease

The visual perception of size in different regions of external space was studied in Parkinson’s disease (PD). A group of patients with worse left-sided symptoms (LPD) was compared with a group with worse right-sided symptoms (RPD) and with a group of age-matched controls on judgements of the relative height or width of two rectangles presented in different regions of external space. The relevant dimension of one rectangle (the ‘standard’) was held constant, while that of the other (the ‘variable’) was varied in a method of constant stimuli. The point of subjective equality (PSE) of rectangle width or height was obtained by probit analysis as the mean of the resulting psychometric function. When the standard was in left space, the PSE of the LPD group occurred when the variable was smaller, and when the standard was in right space, when the variable was larger. Similarly, when the standard rectangle was presented in upper space, and the variable in lower space, the PSE occurred when the variable was smaller, an effect which was similar in both left and right spaces. In all these experiments, the PSEs for both the controls and the RPD group did not differ significantly, and were close to a physical match, and the slopes of the psychometric functions were steeper in the controls than the patients, though not significantly so. The data suggest that objects appear smaller in the left and upper visual spaces in LPD, probably because of right hemisphere impairment.

Dopamine and the representation of the upper visual field: evidence from vertical bisection errors in unilateral Parkinson’s disease

It has been suggested that dopamine is an important neurotransmitter in the brain mechanisms which represent the upper visual field. This idea was tested with a vertical line bisection task in unilateral Parkinson’s disease. Stimuli of a range of lengths were presented on a large screen in three positions (left, centre and right) and at two viewing distances (0.6 and 1.5 m). The patients, who were compared with a group of normal age-matched controls, comprised 16 sufferers from predominantly unilateral disease, 8 with more severe left-sided symptoms (LPD) and 8 with more severe right-sided symptoms (RPD). The LPD group consistently set the bisecting cursor below the midpoint of the stimulus lines, and their bisection error became larger as the length of the line increased. In contrast, the controls set the cursor above the midpoint of the line, an error which also increased with line length. The settings of the RPD group were similar to those of the controls. The results suggest altitudinal neglect in left unilateral PD, and support the hypothesis of dopaminergic involvement in the coding of upper visual space, with the proviso that the perceptual component of this involves the right hemisphere in humans.

Evidence from a line bisection task for visuospatial neglect in Left Hemiparkinson's disease

The perception of extrapersonal space in Parkinson's disease was examined with two line bisection tasks. One was a conventional pencil and paper test, the line bisection section of the Behavioural Inattention Test. In the other, the stimuli were displayed on a large (2×2.4 m) screen and varied in length (48–480 mm) and also in location on the screen (left, centre and right). They were presented at two viewing distances (0.6 and 1.5 m). Subjects remotely adjusted the position of a cursor until it appeared to bisect the stimulus line, using two push-buttons, one in each hand. The PD participants ( n=18) had a marked asymmetry of motor symptoms. They were divided into two groups, those with predominantly left-sided motor symptoms (LPD, n=9), and those with predominantly right-sided motor symptoms (RPD, n=9). The control group ( n=9) were all right-handed. No significant differences between the groups were found on the BIT bisection task. In contrast, when the stimuli were presented on the screen, LPD subjects showed a significant rightward bias in their settings of the cursor, particularly for lines on the left and centre of the screen, which was greater, the longer the stimulus line. The RPD group bisected lines slightly to the left, in common with the control group (pseudo-neglect). In a second experiment, Parkinsonian subjects repeated this task, but with the buttons reversed between the hands, so that the cursor was moved to the left by the right hand, and vice versa, but the pattern of results was the same as in the first experiment. The data suggest a small but reliable neglect in left hemiparkinson's disease, which is contralateral to the non-dominant (and probably worse affected) hemisphere. The dissociation between the response and the bisection error suggests a visuospatial impairment in LPD.

Disruption of estimation of body-scaled aperture width in Hemiparkinson's disease

A group of patients with left-sided symptoms of Parkinson's disease (LPD) was compared with a group of patients with right-sided symptoms (RPD) and with a group of healthy age-matched controls on body-scaled judgements of aperture width. Participants judged whether or not they would fit through a life-sized schematic doorway shown on a large screen. A staircase technique was used to find the door width for which 50% of the judgements were positive. The ratio between this measure and the width of the participant's body at the shoulders (the aperture to shoulder — A/S ratio) was calculated. The A/S ratio was approximately 1.5 in the LPD group, approximately 0.9 in the RPD group, and approximately 1.1 in the control group, suggesting that the visual representation of the doorway (or that of its relationship to perceived body-size) is compressed in LPD (and perhaps expanded in RPD). The A/S ratios were invariant with viewing distance (0.6 or 1.5 m), the contrast polarity of the display (white on dark, or vice versa) and the doorway surround (blank, or vertical or horizontal stripes). The findings are discussed with reference to the neural representation of external space and of the body, and to the motor problems of Parkinson's disease.

Shortened dental arches and periodontal support*

The periodontal support of subjects with shortened dental arches (SDA, n = 74), and of subjects with SDA and free-end removable partial dentures in the lower jaw (SDA and RPD, n = 25) was compared with that of subjects with complete dental arches (CDA, n = 72). The periodontal support was determined by tooth mobility and alveolar bone height, measured on a radiograph, of the distal alveolar bone of the premolars. Significant differences in tooth mobility were found between the three groups of subjects. The relative bone height showed a trend towards lower values for the SDA group and the SDA and RPD group. For some teeth these differences were significant. Premolars that are the most posteriorly located occluding teeth in the dental arch tend to have a lower relative alveolar bone height than premolars in an intermediate location. This effect is more marked in the upper jaw than in the lower jaw. Premolars in the lower jaw, that serve as abutment teeth for free-end RPDs, tend to show lower values for the relative bone height. It is concluded that the differences between the three groups with regard to the periodontal support are small. The large amount of crowns and bridges in both the SDA and SDA and RPD groups, and the dental history of these subjects, resulting in SDA, should be taken into account. However, as indicated by the periodontal breakdown of premolars in some subjects with SDA, the combination of an existing severe periodontal involvement and a SDA is considered to be an unfavourable situation.