Transcranial Direct Current Stimulation of Primary Motor Cortex over Multiple Days Improves Motor Learning of a Complex Overhand Throwing Task

Transcranial direct current stimulation (tDCS) applied to the primary motor cortex (M1) improves motor learning in relatively simple motor tasks performed with the hand and arm. However, it is unknown if tDCS can improve motor learning in complex motor tasks involving whole-body coordination with significant endpoint accuracy requirements. The primary purpose was to determine the influence of tDCS on motor learning over multiple days in a complex over-hand throwing task. This study utilized a double-blind, randomized, SHAM-controlled, between-subjects experimental design. Forty-six young adults were allocated to either a tDCS group or a SHAM group and completed three experimental sessions on three consecutive days at the same time of day. Each experimental session was identical and consisted of overhand throwing trials to a target in a pre-test block, five practice blocks performed simultaneously with 20 min of tDCS, and a post-test block. Overhand throwing performance was quantified as the endpoint error. Transcranial magnetic stimulation was used to obtain motor-evoked potentials (MEPs) from the first dorsal interosseus muscle to quantify changes in M1 excitability due to tDCS. Endpoint error significantly decreased over the three days of practice in the tDCS group but not in the SHAM group. MEP amplitude significantly increased in the tDCS group, but the MEP increases were not associated with increases in motor learning. These findings indicate that tDCS applied over multiple days can improve motor learning in a complex motor tasks in healthy young adults.

Resolution of depressive symptoms in medical inpatients after discharge

OBJECTIVE

Most studies to date demonstrate a high prevalence of depressive symptoms and depressive disorders in general medical inpatients. In order to determine whether these symptoms represent a self limited epiphenomenon of medical illness or evidence of psychiatric comorbidity, assessment of the natural history of such symptoms in this population is necessary. In this study we focused on resolution versus persistence of depressive symptoms in hospitalized medical patients following medical, but not psychiatric, treatment.

METHOD

Every second admission to the acute care medical ward of a VA teaching hospital was assessed for inclusion in the study. Fifty-seven were screened, fifty participated initially, forty-two remained in the study for the one-week post-discharge follow-up, and thirty-three remained at the one-month follow-up. Depressive symptomatology was measured with the Beck Depression Inventory at each time point. Subjects whose scores at follow-ups were above threshold were considered to have persistent symptoms and those whose scores fell below threshold were considered to have resolved. No patients were treated with antidepressants prior to or during the study.

RESULTS

With a conventionally accepted threshold score (14) on the BDI as representing clinically significant depression, roughly half of those patients identified as depressed at the time of admission were nondepressed at both follow-ups. The BDI predicted persistence of depression with a sensitivity of .64 and specificity of .74 at one week and .71 and .73 at one month. Raising the threshold score to 20 raised the sensitivity to 1.00 and the specificity to .95 at one week and 1.00 and .93 at one month.

CONCLUSIONS

Depressive symptoms seen in acutely-ill medical patients can be expected to resolve without potentially-hazardous antidepressant treatment in a significant number of patients. Persistence of depressive symptoms may be better predicted by raising the threshold on commonly used self-report scales.

Informed consent, competency, and the illusion of rationality

Since the advent of informed consent, patients have become more involved in treatment decisions than ever before. To give an informed consent or refusal a patient must be competent to understand the information being presented. Although most authors agree on the need for a structured format for assessing competency, in practice this step is often omitted if the patient's decision "makes sense." In this paper we present two cases in which acutely ill patients gave apparently rational refusals of potentially life-prolonging treatment. Following their recovery, both viewed their earlier decisions as irrational. These cases demonstrate some of the difficulties in assessing competency and rationality in gravely ill patients, and the need for careful evaluation regardless of the apparent rationality of expressed desires.

MMPI profiles of obese men and women

MMPI profiles of 20 male and 20 female patients were chosen at random from the entire patient population (250) of a weight reduction program. Mean scores of both groups were computed for the 10 clinical scales. On the masculinity-femininity scale, female patients scored significantly lower than a normal population, while the male patients had a marginally significant higher mean score. Scores in the respective directions for men and women indicated passivity and non-assertiveness in both groups. Assertiveness training is suggested as an integral part of the behavior modification program in the treatment of obesity