Evaluation of Executive Functions With Functional Near-Infrared Spectroscopy in Euthymic Bipolar and Borderline Personality Disorders.

Introduction: Bipolar disorder (BD) and borderline personality disorder (BPD) are often indistinguishable, given both the key features of impulsivity and emotional dysregulation. This indicates widespread comorbidity and potential misdiagnosis in both groups. Therefore, this study aimed to differentiate BD and BPD by using alterations of brain hemodynamics under the influence of executive tests. Methods: Twenty patients with the euthymic phase of BD and 20 patients with BPD, and 20 healthy control subjects were included in this study. The prefrontal cortex (PFC) hemodynamic responses were evaluated using functional near-infrared spectroscopy (fNIRS) during the Stroop Test and Wisconsin Card Sorting Test (WCST). Results: Left dorsolateral prefrontal cortex (DLPFC) activation was significantly decreased in BPD during both tests. On the other hand, the BD group showed medial PFC hypoactivation during both tests, and this finding is distinct from BPD (p<0.05). Conclusion: Our results indicate that brain hemodynamics during the executive test can highlight differences between BP and BPD. While medial PFC hypoactivation was more prominent in the BP group, DLPFC hypoactivation was more pronounced in the BPD group.

Electrophysiological and kinesiological analysis of deep tendon reflex responses, importance of angular velocity.

Deep tendon reflexes are one of the main parameters of the neurological examination in many diseases. Reflex responses increase in upper motor neuron diseases due to a lack of suprasegmental control such as spasticity and rigidity. This information provided by the reflex response makes it an indispensable element of neurological examination. However, an important limitation is that this assessment is subjective. In this study, EMG and kinesiology measurements were recorded together during the assessment of the patellar T reflex in healthy control, spasticity, and Parkinson's disease groups. Nine kinesiologic and three electrophysiologic features were extracted. We validated the proposed method with three healthy participants by ten repeated measurements on 6 different days and we observed that angular velocity is the most stable parameter. Clustering of different groups determined with K-clustering and artificial neural network used for classification with kinesiological and EMG inputs. Our findings show that reflex grade can be determined with high accuracy (Acc = 98.6) in a large population for both pathological and healthy groups and angular velocity is sufficient for reflex grading. Therefore, we think that our study will contribute to the literature by providing an approach with high reliability and reproducibility in the quantitative assessment of reflexes.

Amplitude and velocity dependence of patellar pendulum triggered by T reflex in Parkinson's rigidity.

OBJECTIVES: The relation between increase of tonus and joint movement velocity is controversial in Parkinson's rigidity. It is accepted that the increase of tonus in rigidity is constant during joint movement, and does not change within all limits of movement. However, there is thoughtful evidence that the change in tonus in rigidity has a correlation with joint movement velocity and amplitude of movement. The pendulum movement that is formed by triggering of the patellar T reflex allows the examination of phasic stretching reflexes and physiological changes of passive stretching. Therefore, the velocity and amplitude properties of tonus in Parkinson's rigidity can be scanned together. MATERIALS AND METHODS: Patellar T reflex-triggered patellar pendulum was recorded in 40 Parkinson's patients. The velocity and amplitude changes in the pendulum were observed according to the rigidity scale. Muscle action potentials were recorded from the rectus femoris muscle and biceps femoris muscles simultaneously via superficial recording electrodes. Knee joint angle changes were recorded with a goniometer. The kinesiological and electromyographic features were compared with those of the control subjects. RESULTS: The number of pendulums decreased significantly, the angle of joint movement decreased, the peak time decreased and the angular velocity slowed down significantly in the Parkinson's group. While the latency of the patellar T reflex did not change significantly, its amplitude decreased, and the onset time of joint movement measured by accelerometer was prolonged. CONCLUSIONS: Parkinson's rigidity has a velocity-dependent component, and this correlates negatively with the rigidity scale.

Mathematical model of patella T-reflex and clinical evaluation with Ashworth scales.

Spasticity is one of the major problems that arise in different neurological diseases and seriously affect the quality of human life. Research on the understanding of mechanism of spasticity remains as important as the studies on the spasticity therapy and rehabilitation. In this study, the spasticity mechanism which develops concerning the upper motor neuron lesions is investigated by modelling "Patella tendon reflex triggered patella pendulum". The mathematical model based on the pendulum phenomenon is developed by solving the curve-fitting problem as finding the curve that best fits a set of data points. Electrophysiological and dynamic measurement data were taken from 76 spastic subjects and 20 healthy participants. The mathematical model is determined by the morphological properties of the goniometric variations. The results denote that the mathematical model containing two clinically relevant parameters -frequency component of the damped oscillatory motion defined as "f 0 " with the maximum angle of the reflex defined as "a 0 " ensures to distinguish spasticity from healthy subjects.

Modified motor unit number index (MUNIX) algorithm for assessing excitability of alpha motor neuron in spasticity.

OBJECTIVE: The understanding of the spasticity mechanism is still a problem in the literature, as its definition can be made on the basis of more than one parameter. Therefore, we studied alpha motor neuron excitability, dynamic changes based on force production, and patellar tendon (T) reflex in spasticity and healthy control groups. METHODS: Alpha motor neuron excitability, force production, and patellar T reflex were evaluated through three different test protocols. Motor Unit Number Index (MUNIX) measurement was applied for understanding motor neuron pool properties in the first protocol. Voluntary force production and patellar T reflex parameters were evaluated by voluntary force production and triggering patellar T reflex. Twenty spasticity and 20 healthy volunteers participated in the study. RESULTS: In the spasticity group, both MUNIX numbers and Motor Unit Size Index (MUSIX) numbers were lower than those in the control group. The results for the Ideal Case Motor Unit Count (ICMUC) parameter show that there is no significant difference between spasticity and healthy individuals for low-level contractions, whereas there is a significant difference for high-level contractions (p < 0.05). In the spasticity group, an increase was observed in the ratio of maximal voluntary force to the T reflex triggered force production (Tf/Vf). CONCLUSION: Spasticity and healthy subjects can be distinguished easily and clearly by evaluating the changes in both kinesiological and electrophysiological findings and the decreasing threshold in the alpha motor neuron pool. SIGNIFICANCE: This study shows that such combined methods, which allow the evaluation of the alpha motor neuron pool, as well as kinesiological and electrophysiological parameters, are tools that cannot be overlooked in understanding spasticity.