Reassurance seeking and depression in adults with mild intellectual disability.

BACKGROUND: Adults with intellectual disability (ID) experience a high prevalence of depression. Yet, little research has investigated interpersonal processes related to depression in this population. In the general population, depressed persons behave in ways that elicit negative and rejecting reactions from others. In particular, excessive reassurance seeking, defined as excessively and persistently seeking assurance from others that one is lovable and worthy, indirectly contributes to depressive symptoms through evoking negative and rejecting social interactions. We examined the relation between excessive reassurance seeking, negative and rejecting social interactions and depression in adults with mild ID. METHOD: Eighty-seven adults with mild ID and staff completed the Glasgow Depression Scale for people with a Learning Disorder and the Reassurance-Seeking Scale. In addition, adults with mild ID reported on their experience of negative social interactions, and staff rated their relative preference to interact with the adult with mild ID. A meditational model of the indirect effect of excessive reassurance seeking on depressive symptoms via negative and rejecting social interactions was tested. RESULTS: Excessive reassurance seeking was positively related to depressive symptoms. Negative and rejecting interactions partially mediated the relation between excessive reassurance seeking and depressive symptoms. CONCLUSIONS: Findings identify an important interpersonal process in depression. Efforts to educate staff and adults with mild ID about excessive reassurance seeking and ways to alter it may be useful in treating depression.

An implant for chronic selective stimulation of nerves.

An implantable stimulator system has been developed for nerve stimulation. The system is capable of stimulating selectively, either by fibre position, fibre size or by sending action potentials in one direction only, based on the use of nerve cuffs. The stimulator produces either quasi-trapezoidal current pulses, to allow anodal blocking, or conventional rectangular-shaped current pulses, of amplitude 20 microA to 5 mA (in 20 microA steps) with duration of 16 micros to 1 ms (in 8 micros steps). For safety, both active and passive charge balancing is used. The amplitude of the active charge-balancing phase can be varied between 1/7 and 1/47 of the pulse amplitude. During manufacture, each implant is customised so as to drive either 6 quasi-tripolar (dipolar), 4 tripolar or 2 pentapolar cuffs. Possible applications of the device are: improved defaecation and bladder voiding after spinal cord injury, by stimulation of the sacral motor roots; neuromodulation to reduce hyperreflexia without concomitant muscle contractions; in stroke patients, to enable balanced inversion-eversion while dorsiflexing the ankle by stimulating the peroneal nerve. It may also be used in chronic animal experiments.This paper describes the implant system, its hardware and communication protocol, and shows results from in vitro tests of the device and the first acute anodal-blocking experiments in pigs.

Control of FES thumb force using slip information obtained from the cutaneous electroneurogram in quadriplegic man.

A tetraplegic volunteer was implanted with percutaneous intramuscular electrodes in hand and forearm muscles. Furthermore, a sensory nerve cuff electrode was implanted on the volar digital nerve to the radial side of the index finger branching off the median nerve. In laboratory experiments a stimulation system was used to produce a lateral grasp (key grip) while the neural activity was recorded with the cuff electrode. The nerve signal contained information that could be used to detect the occurrence of slips and further to increase stimulation intensity to the thumb flexor/adductor muscles to stop the slip. Thereby the system provided a grasp that could catch an object if it started to slip due to, e.g., decreasing muscle force or changes in load forces tangential to the surface of the object. This method enabled an automatic adjustment of the stimulation intensity to the lowest possible level without loosing the grip and without any prior knowledge about the strength of the muscles and the weight and surface texture of the object.

Restoration of lateral hand grasp using natural sensors.

A closed-loop control system for controlling the key grip of a C6 tetraplegic patient was developed. Natural sensors served as the source of the feedback signal. The neural signals from cutaneous receptors were picked up by an implanted cuff electrode placed around the radial branch of the median nerve innervating the lateral part of the index finger. Mechanical stress applied to the skin, like pressure and slips, resulted in an increase in amplitude of the recorded neural signal. The goal of the study was to determine whether the recorded neural signals were able to indicate the slip of an object during lateral grasp and whether the slip could be stopped by increasing the grasp force through functional electrical stimulation of the thumb adductor and flexor.