Biomedical subjects

Colleen K Loo

Publications and source records attributed to Colleen K Loo.

6 recordsLinked to original sources

PubMed2006

A sham-controlled trial of the efficacy and safety of twice-daily rTMS in major depression.

BACKGROUND: Studies of repetitive transcranial magnetic stimulation (rTMS) in depression have mostly involved once-daily treatment, with positive but modest clinical results. This study tested the efficacy and safety of twice-daily rTMS over 2 weeks. METHOD: Thirty-eight depressed subjects enrolled in a double-blind, sham-controlled trial of twice-daily rTMS (left prefrontal cortex, 10 Hz, 110% intensity, 1500 stimuli per session) over 2 weeks. Mood and neuropsychological functioning were assessed weekly by blind raters, using the Montgomery-Asberg Depression Rating Scale (MADRS) as the primary outcome measure, plus the Hamilton Rating Scale for Depression (HRSD) and self-report measures. After the blind period, 22 subjects continued with once-daily rTMS to receive a total of 6 weeks of active rTMS. RESULTS: Subjects were moderately treatment resistant. Active treatment resulted in significantly greater improvement than sham over the 2-week blind period on one outcome measure only (MADRS p<0.05). Subjects showed further improvement over the 6 weeks of active rTMS. Neuropsychological test scores did not change significantly. CONCLUSIONS: rTMS given twice daily was effective and safe, with no adverse neuropsychological effects.

Adult↗

PubMed2006

Stimulus waveform influences the efficacy of repetitive transcranial magnetic stimulation.

BACKGROUND: Optimising stimulus parameters is important in maximising the efficacy of repetitive transcranial magnetic stimulation (rTMS) in treatment applications. RTMS over motor cortex has been reported as more effective in producing corticospinal inhibition when a monophasic rather than a biphasic stimulus waveform is used. However, non-optimal coil orientation and high intensities of monophasic rTMS may have influenced previous results. METHODS: In eight healthy subjects, we measured motor evoked potentials (MEPs) in a hand muscle after monophasic and biphasic rTMS (1 Hz for 15 min) over the motor cortex with the coil always in the optimal orientation. MEPs were evoked by both monophasic and biphasic stimuli. RESULTS: MEPs were initially significantly reduced after monophasic but not biphasic rTMS. However, a late reduction was seen after biphasic rTMS. LIMITATIONS: These motor cortical findings may not be directly applicable to prefrontal rTMS. CONCLUSIONS: This study confirms that low frequency rTMS with monophasic pulses produces more corticospinal inhibition than with biphasic pulses, even when the direction of current and intensity are as well-matched as possible.

Adult↗

PubMed2006

Transcranial magnetic stimulation for depression.

OBJECTIVE: To review the accumulated literature on the efficacy, safety and predictors of response for repetitive transcranial magnetic stimulation (rTMS) in the treatment of depression. METHODS: A descriptive review of the more than 25 published sham-controlled rTMS studies in depression was undertaken, focusing on reported meta-analyses as well as individual trial reports. Potential determinants of efficacy were examined, including the form of shams employed, stimulation parameters and clinical features. RESULTS: There is now clear evidence for the statistical superiority of left-prefrontal high frequency rTMS compared with sham therapy. However, the clinical benefits are marginal in the majority of reports. There is also still considerable uncertainty concerning the optimal stimulation parameters. Those clinical features which appear to be associated with greater response include younger age, lack of refractoriness to antidepressants and no psychotic features. CONCLUSIONS: Current studies confirm statistical efficacy, but insubstantive clinical benefit. Large multicentre studies currently underway should clarify if rTMS should be approved by regulatory agencies for widespread clinical availability. Furthermore, there is a need to clarify the preferred parameters for administering this treatment.

Major Depressive Disorder↗

PubMed2006

Recent advances in optimizing electroconvulsive therapy.

This review aims to summarize and critically evaluate the evidence for recent advances and alternative approaches in electroconvulsive therapy (ECT) technique. Novel developments in ECT research are also mentioned. An EMBASE literature search was undertaken of clinical trials, case reports and research updates on novel and alternative approaches in ECT practice and research, including alternative electrode placements, variations in stimulus configuration, and novel developments (magnetic seizure therapy, focal electrical stimulation). The evidence for these approaches is reviewed, and implications for the optimizing of ECT in clinical practice are discussed. Evidence from studies suggests that unilateral ECT be given at substantially suprathreshold doses (at least 6 times seizure threshold) for maximizing efficacy, while bilateral ECT is likely to be effective at doses of 1.5-2.5 times seizure threshold. There is some evidence to support the use of bifrontal ECT, although further research is required to establish its efficacy and side-effects relative to standard unilateral and bilateral electrode placements. Other alternative electrode placements have been minimally studied. More advantageous efficacy side-effect outcomes may be achieved by reducing the pulse width and/or frequency of the ECT stimulus. Lastly, novel developments using alternative means of seizure induction (magnetic fields, focal electrical stimulation) may hold promise for the future. Clinical practice should be guided by a careful appraisal of the available evidence for alternative approaches in ECT technique.

Electroconvulsive Therapy↗

PubMed2005

A review of the efficacy of transcranial magnetic stimulation (TMS) treatment for depression, and current and future strategies to optimize efficacy.

BACKGROUND: There is a growing interest in extending the use of repetitive transcranial magnetic stimulation (rTMS) beyond research centres to the widespread clinical treatment of depression. Thus it is timely to critically review the evidence for the efficacy of rTMS as an antidepressant treatment. Factors relevant to the efficacy of rTMS are discussed along with the implications of these for the further optimization of rTMS. METHOD: Clinical trials of the efficacy of rTMS in depressed subjects are summarized and reviewed, focusing mainly on sham-controlled studies and meta-analyses published to date. RESULTS: There is a fairly consistent statistical evidence for the superiority of rTMS over a sham control, though the degree of clinical improvement is not large. However, this data is derived mainly from two-week comparisons of rTMS versus sham, and evidence suggests greater efficacy with longer treatment courses. Studies so far have also varied greatly in approaches to rTMS stimulation (with respect to stimulation site, stimulus parameters etc) with little empirical evidence to inform on the relative merits of these approaches. LIMITATIONS: Only studies published in English were reviewed. Many of the studies in the literature had small sample sizes and different methodologies, making comparisons between studies difficult. CONCLUSIONS: Current published studies and meta-analyses have evaluated the efficacy of rTMS as given in treatment paradigms that are almost certainly suboptimal (e.g of two weeks' duration). While the data nevertheless supports positive outcomes for rTMS, there is much scope for the further refinement and development of rTMS as an antidepressant treatment. Ongoing research is critical for optimizing the efficacy of rTMS.

Depressive Disorder↗

PubMed2005

Supraorbital edema induced by electroconvulsive therapy.

This is a case report of an unusual side effect-unilateral supraorbital edema occurring immediately after electroconvulsive therapy ECT during each treatment occasion-in a depressed patient who was otherwise well. The affected upper eyelid appeared normal before ECT with no history of injury or abnormality. Trauma during ECT, allergic reaction to anesthetic agents, and complications of manual ventilation were found to be unlikely causes. The supraorbital edema occurred as an isolated, benign, complication of ECT and resolved spontaneously.

Major Depressive Disorder↗