The threshold tracking nerve conduction study technique: Experience of clinical users unfamiliar with a research-grade neuronal excitability system.

Objective: To 1) explore if clinical electrophysiologists with different degrees of experience performing standard nerve conduction studies could run a threshold tracking nerve conduction study (TTNCS) protocol and 2) learn how clinical users view a research-grade TTNCSs neuronal excitability system. Methods: Five clinical electrophysiologists conducted a TTNCS session using QTracS and then completed a questionnaire describing their impressions. Results: All of the electrophysiologists completed the QTracS protocol on an initial attempt. Perceived strengths comprised the ease of preparatory steps and quick protocol speed. Identified drawbacks included an unwieldly user-interface. The electrophysiologists indicated that knowledge of TTNCS principles and applications would be critical for incorporation of the method into clinical use. Conclusions: This pilot study suggests that clinical electrophysiologists can carry out TTNCSs with a research-grade system. The development of a more user-friendly program, along with dedicated education and training, could lead to wider application of the TTNCS technique. Significance: Considered together with clinical presentation and other biomarkers, increased use of TTNCSs could provide improved assessment of neuromuscular disease and treatment response.

Noninvasive beat-to-beat finger arterial pressure monitoring during orthostasis: a comprehensive review of normal and abnormal responses at different ages.

Over the past 30 years, noninvasive beat-to-beat blood pressure (BP) monitoring has provided great insight into cardiovascular autonomic regulation during standing. Although traditional sphygmomanometric measurement of BP may be sufficient for detection of sustained orthostatic hypotension, it fails to capture the complexity of the underlying dynamic BP and heart rate responses. With the emerging use of noninvasive beat-to-beat BP monitoring for the assessment of orthostatic BP control in clinical and population studies, various definitions for abnormal orthostatic BP patterns have been used. Here, age-related changes in cardiovascular control in healthy subjects will be reviewed to define the spectrum of the most important abnormal orthostatic BP patterns within the first 180 s of standing. Abnormal orthostatic BP responses can be defined as initial orthostatic hypotension (a transient systolic BP fall of >40 mmHg within 15 s of standing), delayed BP recovery (an inability of systolic BP to recover to a value of >20 mmHg below baseline at 30 s after standing) and sustained orthostatic hypotension (a sustained decline in systolic BP of ≥20 mmHg occurring 60-180 s after standing). In the evaluation of patients with light-headedness, pre(syncope), (unexplained) falls or suspected autonomic dysfunction, it is essential to distinguish between normal cardiovascular autonomic regulation and these abnormal orthostatic BP responses. The prevalence, clinical relevance and underlying pathophysiological mechanisms of these patterns differ significantly across the lifespan. Initial orthostatic hypotension is important for identifying causes of syncope in younger adults, whereas delayed BP recovery and sustained orthostatic hypotension are essential for evaluating the risk of falls in older adults.

Relation between heart rate and problem behaviors.

A new methodological approach for understanding self-injury, aggression, and property destruction exhibited by individuals with severe developmental disabilities was evaluated in this descriptive study. Measures of heart-rate changes before, during, and after episodes of problem behavior were obtained in real time. Unique patterns of heart rate and problem behavior were documented for each participant. Heart rate, identified as an indicator of negative arousal, was reliably associated with higher scores of perceived distress. These results indicate that further research is needed to examine the link between problem behavior and physiology. The study also suggests that physiological measurement can be included in the functional assessment process to further our understanding of the mechanisms underlying problem behavior.

The neurology of depression. Cognitive and behavioral deficits with focal findings in depression and resolution after electroconvulsive therapy.

Deficits in cognition and behavior have frequently been described in severely depressed patients. Recent reports have drawn attention to focal left-sided neurologic findings occurring in depression. We describe a depressed patient with marked cognitive and behavioral impairment and focal left-sided signs. The depression, mental status deficits, and physical findings all resolved after electroconvulsive therapy.

Syndrome of opsoclonus-myoclonus caused by Coxsackie B3 infection.

Coxsackie B3 was cultured from 2 children who presented within two weeks of each other from the Cape Cod, Massachusetts, area showing opsoclonus and myoclonus. The organism was recovered from the cerebrospinal fluid of 1 patient and from the stools of both. Both children had cerebrospinal fluid pleocytosis and gradual, spontaneous resolution of their symptoms.