Symptom severity is associated with leftward lateralization upon contextual modulation of visual vertical in patients with schizophrenia

BackgroundContextual processing dysfunction in patients with schizophrenia (SCZ) is not uniform and task-dependent. In SCZ, studies on the rod and frame test (RFT), which evaluates contextual modulation of verticality perception, are sparse. A main study that utilized a two-alternative forced choice design for judging rod verticality reported equivalent strength of RFT contextual modulation in healthy controls and SCZ. The current study aims to uncover any potential differences in contextual modulation between controls and SCZ with an adjustment method on a computerized RFT.Materials and methodsA total of 17 healthy controls and 15 SCZ aligned an oriented rod to their perceived vertical with a computer mouse under four randomized frame presentations: absent frame, non-tilted (Frame0°), or tilted by 18 degrees leftward (Frame–18°) or rightward (Frame+18°). Rod deviation error was assigned a negative or positive value when aligned leftward or rightward, respectively, of 0°. Signed and absolute errors, the rod and frame effect (RFE), and intra-individual variability (inconsistency) were used for analysis.ResultsThere was no group difference in rod alignment errors or derived measures, except that SCZ displayed greater inconsistency in rod alignment, compared to controls. The negative symptom scale (PANSS-N) scores correlated positively with the variability measure and with unsigned Frame–18° error.ConclusionsOnly the variability measure was sensitive enough to distinguish between controls and SCZ. SCZ with more severe negative symptoms had larger variability in rod alignment, probably reflecting a state of indifference. The larger deviation errors only with a leftward tilted frame, as PANSS-N scores increased, may indicate a lateralized attentional abnormality that is correlated with severity of symptoms in SCZ

High-normal blood glucose levels may be associated with decreased spatial perception in young healthy adults.

The negative effects of high normal glucose on cognitive function were previously reported in euglycemic individuals of middle age and the elderly population. This study aimed at examining the effect of baseline blood glucose levels on spatial ability, specifically verticality perception on the computerized rod and frame test (CRFT) in young healthy adults. 63 healthy male medical students (age range from 18-23 years), of whom 30 were non-fasting outside the month of Ramadan and 33 fasting during Ramadan of the year 2016, were recruited in order to create varying degrees of glycemia during which verticality perception was carried out. Baseline blood glucose reading was obtained prior to commencing the CRFT test. Blood glucose levels at the time of testing decreased as the duration between the last meal and testing increased. A blood glucose range of 62-117 mg/dl was achieved among participants for this study. Linear regression analysis showed that blood glucose level at testing correlated positively with all alignment spatial error parameters, indicating a probable reduction of spatial perception ability with higher blood glucose levels. These results are consistent with other cognitive studies in older healthy humans and emphasize the critical impact of early glucose dys-homeostasis on cognitive function. They also indicate that elevated blood glucose may affect cognitive functioning outside of the usual complications of diabetes

Postnatal development of electrical activity in the hamster spinal cord studied in an in vitro preparation

The dorsal root reflex (DRR) is a volley of antidromic action potentials that can be recorded emerging from dorsal roots on stimulation of an adjacent dorsal root. In addition to the evoked DRR, the hamster isolated spinal cord maintained in Mg-freeACSF at 25-27o C exhibits characteristic bursts of spontaneous action potentials emerging from the cord along the dorsal roots or in the dorsal horn. It was shown that in barbiturate anaesthetized cats, the DRR does not appear before day 4 postnatal and increases to a maximum within the fourth week of life, before declining to lower adult values (Bawa, 1988). The aim of this project is to study the developmental changes in the frequency and pattern of spontaneous activity, and in the pharmacological sensitivity during the first 7 weeks of life. The study revealed that the pattern of spontaneous firing in animals younger than two weeks, was principally single action potentials, giving a single mode on Inter-Spike Interval plots. Above the age of three weeks, dorsal root/horn spontaneous activity was dominated by bursts of action potentials shown as bimodal ISI plots. Cross correlation studies on dorsal horn spontaneous activity between two sites of recording showed that the indices of cross correlation increase with age, suggesting that intersegmental links mature postnatally in the cord. Lumbar and sacral dorsal roots were stimulated at twice threshold, and the evoked responses in the dorsal horn were used to construct Peri-Stimulus Time Histograms. Responses were evoked at all ages, and appeared as a peak on the PSTH. In animals older than 3 weeks, this was followed by a depression of spontaneous activity between 200 and 400 ms after stimulation, whereas in younger animals, the number of action potentials recorded during this period was increased above the spontaneous level. This indicates that excitatory processes responsible for generation of the DRR are active within 1 week of birth, whereas inhibitory events develop later in life. The pharmacological studies show that the adult pattern of spontaneous activity in dorsal roots and dorsal horn are insensitive to addition of 1 mM Mg2+ or 5&mu;M D-AP5. Incords from young animals, this activity was depressed by both Mg^2+and AP5, indicating an involvement of NMDA receptors in the generation of spontaneous activity in the young, but not in the mature animals. Studies of the effects of addition of NMDA for 10 mins on the frequency of spontaneous activity revealed that in 5-6 week old animals, the frequency was depressed to 66.4&#37; of the control value. In the second week of life, NMDA produced a complex sequence of changes in the firing frequency. The predominant pattern was a short latency excitation (1-5 mins) followed by a decrease in the firing rate which persisted for the remainder of the 10 minute period. These results suggest that NMDA receptors may be more numerous or more functional in young animals.</p

Symptom severity is associated with leftward lateralization upon contextual modulation of visual vertical in patients with schizophrenia.

Background: Contextual processing dysfunction in patients with schizophrenia (SCZ) is not uniform and task-dependent. In SCZ, studies on the rod and frame test (RFT), which evaluates contextual modulation of verticality perception, are sparse. A main study that utilized a two-alternative forced choice design for judging rod verticality reported equivalent strength of RFT contextual modulation in healthy controls and SCZ. The current study aims to uncover any potential differences in contextual modulation between controls and SCZ with an adjustment method on a computerized RFT. Materials and methods: A total of 17 healthy controls and 15 SCZ aligned an oriented rod to their perceived vertical with a computer mouse under four randomized frame presentations: absent frame, non-tilted (Frame0°), or tilted by 18 degrees leftward (Frame-18°) or rightward (Frame+18°). Rod deviation error was assigned a negative or positive value when aligned leftward or rightward, respectively, of 0°. Signed and absolute errors, the rod and frame effect (RFE), and intra-individual variability (inconsistency) were used for analysis. Results: There was no group difference in rod alignment errors or derived measures, except that SCZ displayed greater inconsistency in rod alignment, compared to controls. The negative symptom scale (PANSS-N) scores correlated positively with the variability measure and with unsigned Frame-18° error. Conclusions: Only the variability measure was sensitive enough to distinguish between controls and SCZ. SCZ with more severe negative symptoms had larger variability in rod alignment, probably reflecting a state of indifference. The larger deviation errors only with a leftward tilted frame, as PANSS-N scores increased, may indicate a lateralized attentional abnormality that is correlated with severity of symptoms in SCZ

Preliminary Blood Pressure Screening in a Representative Sample of Extremely Obese Kuwaiti Adolescents

A relationship between blood pressure (BP) and obesity has been found in young adults, but no data are available for adolescents in Kuwait. 257 adolescent (11–19 years) participants were categorized into two groups according to their BMI; 48 nonobese (21 males: 43.7% and 27 females: 56.3%) with mean age of years and 209 obese (128 males: 61.25% and 81 females: 38.75%) with mean age of years. The mean BMI was  kg/m2 for the nonobese group and  kg/m3 for the obese group. Most BP measures based on a single screening were significantly higher in the obese group. The prevalence of elevated BP was significantly higher in the obese subjects (nonobese: 13%; obese: 63%; ). In the obese group, there was a significant positive correlation between total sample BMI and all BP measures except the pulse pressure. There was a similar rate of elevated blood pressure between males and females (64% versus 60%; ). For both isolated systolic elevated BP and isolated diastolic elevated BP, the prevalences were comparable between the males (systolic: 42%; diastolic: 5%) and females (systolic: 34%; diastolic: 14%). Only systolic BP was positively correlated with BMI in obese adolescent males (Spearman ; ), with a significant correlation between BMI with diastolic (Spearman ; ) and mean BP (Spearman ; ) in females

Blood glucose levels and verticality perception.

<p>Relationship between baseline glucose level and unsigned spatial measures of verticality on CRFT in non-fasting and Ramadan fasting participants pooled together (n = 63).</p

Duration of food omission and glucose levels.

<p>Effect of time spent without food on blood glucose level in both non-fasting (n = 30) and Ramadan fasting (n = 33) participants.</p

Measures of glucose and CRFT unsigned spatial errors under different frame conditions.

<p>Measures of glucose and CRFT unsigned spatial errors under different frame conditions.</p

Computer set up for SVV recording.

<p>Concealment of the vertical edges of the laptop to obscure from participants any cues of verticality in the laptop frame.</p

Presentations of “rod” and frame during testing.

<p>The order of presentation was randomly assigned by the computer.</p