Opposite effects of high and low frequency rTMS on mood in depressed patients: relationship to baseline cerebral activity on PET.

BACKGROUND: Optimal parameters of rTMS for antidepressant efficacy in general, or within patients, have not been adequately delineated. METHODS: Using a double-blind, sham-controlled, cross-over design, 22 adult patients with treatment refractory major depression (n=9; bipolar disorder, depressed phase) were randomized to active rTMS (20-Hz or 1-Hz) or sham rTMS conditions and given 5 rTMS treatments per week for two weeks. Repetitive TMS was administered at 100% of motor threshold for 1600 pulses over the left prefrontal cortex using a figure-eight coil. Patients initially randomized to sham rTMS were then exposed to two weeks of active rTMS with each frequency under blinded conditions. Those who received active 20-Hz and 1-Hz rTMS were crossed over to the opposite frequency for two weeks. Improvement in Hamilton Depression ratings were assessed after each two-week treatment phase. PET imaging was used to evaluate the patient's baseline absolute regional cerebral activity (blood flow and metabolism) as potential predictor of clinical response. RESULTS: Changes in depression severity on 1-Hz and 20-Hz rTMS were inversely correlated. PET scans with baseline hypoperfusion (but not hypometabolism) were associated with better improvement on 20-Hz rTMS as predicted. LIMITATIONS: The magnitude of the clinical change with either frequency at 100% motor threshold was not robust, and larger studies with higher intensities of rTMS for longer durations of time should be explored. CONCLUSIONS: High and low frequency rTMS exerts differential effects on depressed mood within individual subjects. The brain activity predictors and correlates of an optimal antidepressant response to rTMS remain to be better defined.

Brain effects of TMS delivered over prefrontal cortex in depressed adults: role of stimulation frequency and coil-cortex distance.

Relative regional brain blood flow was measured in 23 clinically depressed adults by using ECD SPECT at baseline and again during actual prefrontal transcranial magnetic stimulation (TMS) following 5 daily sessions of TMS. TMS over prefrontal cortex caused increased activity in cortex directly under the stimulation (inversely correlated with distance from scalp to cortex) and decreased activity in remote regions (anterior cingulate and anterior temporal poles). High-frequency rTMS (20 Hz) caused more relative flow immediately below the TMS coil than did low-frequency rTMS (5 Hz). Confirming the hypotheses tested, repeated daily TMS over the prefrontal cortex in medication-free depressed adults appears to change both local and remote blood flow in a manner that may also depend on the frequency of stimulation and coil to outer cortex distance.

Lack of adverse cognitive effects of 1 Hz and 20 Hz repetitive transcranial magnetic stimulation at 100% of motor threshold over left prefrontal cortex in depression.

OBJECTIVE: The potential therapeutic effects of repetative transcranial magnetic stimulation (rTMS) are being examined in various neuropsychiatric illnesses. This study assesses the cognitive performance of depressed patients receiving high or low frequency rTMS for 10 days. METHODS: 18 depressed patients participated in a randomized double-blind cross-over study exploring the antidepressant effects of 2 weeks (10 daily) of sham, 1 Hz, or 20 Hz rTMS administered over the left dorsolateral prefrontal cortex at 100% of motor threshold (MT). A subgroup completed a battery of cognitive tests at baseline and following each 2-week phase of treatment, and differences in performance were assessed using paired t -tests and were correlated with the degree of clinical improvement using Hamilton Depression Rating Scale scores. RESULTS: There were no major changes in cognitive test scores as a result of 10 days of either 1 Hz or 20 Hz rTMS. Moreover, any minor attenuations in cognition were not related to the degree of clinical improvement. CONCLUSIONS: Cognitive functioning in many domains following 2 weeks of 1 Hz or 20 Hz rTMS at 100% MT over the left dorsolateral prefrontal cortex in depressed patients is not disrupted.

Effects of mood and subtype on cerebral glucose metabolism in treatment-resistant bipolar disorder.

BACKGROUND: Functional brain imaging studies in unipolar and secondary depression have generally found decreased prefrontal cortical activity, but in bipolar disorders findings have been more variable. METHODS: Forty-three medication-free, treatment-resistant, predominantly rapid-cycling bipolar disorder patients and 43 age- and gender-matched healthy control subjects had cerebral glucose metabolism assessed using positron emission tomography and fluorine-18-deoxyglucose. RESULTS: Depressed bipolar disorder patients compared to control subjects had decreased global, absolute prefrontal and anterior paralimbic cortical, and increased normalized subcortical (ventral striatum, thalamus, right amygdala) metabolism. Degree of depression correlated negatively with absolute prefrontal and paralimbic cortical, and positively with normalized anterior paralimbic subcortical metabolism. Increased normalized cerebello-posterior cortical metabolism was seen in all patient subgroups compared to control subjects, independent of mood state, disorder subtype, or cycle frequency. CONCLUSIONS: In bipolar depression, we observed a pattern of prefrontal hypometabolism, consistent with observations in primary unipolar and secondary depression, suggesting this is part of a common neural substrate for depression independent of etiology. In contrast, the cerebello-posterior cortical normalized hypermetabolism seen in all bipolar subgroups (including euthymic) suggests a possible congenital or acquired trait abnormality. The degree to which these findings in treatment-resistant, predominantly rapid-cycling patients pertain to community samples remains to be established.

A placebo-controlled study of lamotrigine and gabapentin monotherapy in refractory mood disorders.

There is a pressing need for additional treatment options for refractory mood disorders. This controlled comparative study evaluated the efficacy of lamotrigine (LTG) and gabapentin (GBP) monotherapy versus placebo (PLC). Thirty-one patients with refractory bipolar and unipolar mood disorders participated in a double-blind, randomized, crossover series of three 6-week monotherapy evaluations including LTG, GBP, and PLC. There was a standardized blinded titration to assess clinical efficacy or to determine the maximum tolerated daily dose (LTG 500 mg or GBP 4,800 mg). The primary outcome measure was the Clinical Global Impressions Scale (CGI) for Bipolar Illness as supplemented by other standard rating instruments. The mean doses at week 6 were 274 +/- 128 mg for LTG and 3,987 +/- 856 mg for GBP. Response rates (CGI ratings of much or very much improved) were the following: LTG, 52% (16/31); GBP, 26% (8/31); and PLC, 23% (7/31) (Cochran's Q = 6.952, df = 2, N = 31, p = 0.031). Post hoc Q differences (df = 1, N = 31) were the following: LTG versus GBP (Qdiff = 5.33, p = 0.011); LTG versus PLC (Qdiff = 4.76, p = 0.022); and GBP versus PLC (Qdiff = 0.08, p = 0.70). With respect to anticonvulsant dose and gender, there was no difference between the responders and the nonresponders. The agents were generally well tolerated. This controlled investigation preliminarily suggests the efficacy of LTG in treatment-refractory affectively ill patients. Further definition of responsive subtypes and the role of these medications in the treatment of mood disorders requires additional study.

A controlled trial of daily left prefrontal cortex TMS for treating depression.

BACKGROUND: Transcranial magnetic stimulation (TMS) is a new technology for noninvasively stimulating the brain. Several studies have suggested that daily stimulation of the left prefrontal cortex with TMS for 2 weeks has probable antidepressant effects. We conducted a parallel-design, double-masked, sham-controlled study to address whether 2 weeks of daily TMS over the left prefrontal cortex has antidepressant activity greater than sham. METHODS: Thirty medication-free adult outpatients with nonpsychotic, major depressive (n = 21) or bipolar (n = 9) (depressed phase) disorder who were in a current major depression (Hamilton Rating Scale for Depression [HRSD] 21-item score of >18) were treated each weekday for 2 weeks. Subjects were randomly assigned to receive either daily active (20 subjects) or sham (10 subjects) stimulation. Additionally, the 20 active subjects were equally divided between slower (5 Hz) and faster (20 Hz) frequency treatment. Antidepressant response was defined as greater than a 50% improvement in the baseline HRSD. RESULTS: Active TMS resulted in significantly more responders (9/20) than did sham (0/10) (chi(2) = 6.42, p <.01). The number of responders did not differ significantly between the two active cells (3/10 faster and 6/10 slower). Expressed as a percent change from baseline, active TMS subjects had significantly greater improvement on the Beck Depression Inventory as well as the Hamilton Anxiety Rating Scale than did those who received sham. CONCLUSIONS: Daily left prefrontal TMS for 2 weeks significantly reduced depression symptoms greater than did sham. The two forms of active TMS treatment did not differ significantly.

Opposite effects of high and low frequency rTMS on regional brain activity in depressed patients.

BACKGROUND: High (10-20 Hz) and low frequency (1-5 Hz) repetitive transcranial magnetic stimulation (rTMS) have been explored for possible therapeutic effects in the treatment of neuropsychiatric disorders. As part of a double-blind, placebo-controlled, crossover study evaluating the antidepressant effect of daily rTMS over the left prefrontal cortex, we evaluated changes in absolute regional cerebral blood flow (rCBF) after treatment with 1- and 20-Hz rTMS. Based on preclinical data, we postulated that high frequency rTMS would increase and low frequency rTMS would decrease flow in frontal and related subcortical circuits. METHODS: Ten medication-free, adult patients with major depression (eight unipolar and two bipolar) were serially imaged using (15)O water and positron emission tomography to measure rCBF. Each patient was scanned at baseline and 72 hours after 10 daily treatments with 20-Hz rTMS and 10 daily treatments with 1 Hz rTMS given in a randomized order. TMS was administered over the left prefrontal cortex at 100% of motor threshold (MT). Significant changes in rCBF from pretreatment baseline were determined by paired t test. RESULTS: Twenty-hertz rTMS over the left prefrontal cortex was associated only with increases in rCBF. Significant increases in rCBF across the group of all 10 patients were located in the prefrontal cortex (L > R), the cingulate gyrus (L >> R), and the left amygdala, as well as bilateral insula, basal ganglia, uncus, hippocampus, parahippocampus, thalamus, and cerebellum. In contrast, 1-Hz rTMS was associated only with decreases in rCBF. Significant decreases in flow were noted in small areas of the right prefrontal cortex, left medial temporal cortex, left basal ganglia, and left amygdala. The changes in mood following the two rTMS frequencies were inversely related (r = -.78, p <.005, n = 10) such that individuals who improved with one frequency worsened with the other. CONCLUSIONS: These data indicate that 2 weeks of daily 20-Hz rTMS over the left prefrontal cortex at 100% MT induce persistent increases in rCBF in bilateral frontal, limbic, and paralimbic regions implicated in depression, whereas 1-Hz rTMS produces more circumscribed decreases (including in the left amygdala). These data demonstrate frequency-dependent, opposite effects of high and low frequency rTMS on local and distant regional brain activity that may have important implications for clinical therapeutics in various neuropsychiatric disorders.

Emerging trends in the treatment of rapid cycling bipolar disorder: a selected review.

Recent evidence suggests that lithium therapy (even as supplemented by antidepressants and neuroleptics) is inadequate for the majority of patients with bipolar illness, and particularly those with rapid cycling. Valproate and carbamazepine have emerged as adjuncts and alternatives, but they, too, often require additional approaches with lithium, thyroid hormones, and other putative mood stabilizers, including nimodipine (and related dihydropyridine calcium channel blockers), lamotrigine, gabapentin, topiramate, and the atypical neuroleptics. Evaluating how these agents and the unimodal antidepressants are optimally applied and sequenced in the treatment of bipolar illness with its multiple subtypes, patterns and comorbidities will require much future investigation and the development of new methodological clinical trial approaches.

Treatment of ataxia in isolated vitamin E deficiency caused by alpha-tocopherol transfer protein deficiency.

Dysfunction of the alpha-tocopherol transfer protein causes ataxia with isolated vitamin E deficiency. A 14-year-old male patient presented with ataxia and mental symptoms caused by a homozygous (552G-->A) alpha-tocopherol transfer protein mutation. After initiation of high-dosage alpha-tocopherol therapy, the organic mental syndrome disappeared and cognitive function improved rapidly. Neurologic recovery, however, was slow and incomplete.

Wheat kernel ingestion protects from progression of muscle weakness in mdx mice, an animal model of Duchenne muscular dystrophy.

A simple, reproducible test was used to quantify muscle weakness in mdx mice, an animal model of Duchenne muscular dystrophy. The effect of bedding on wheat kernels and of dietary supplementation of alpha-tocopherol on the progression of muscle weakness was investigated in mdx mice. When measured during the first 200 d of life, mdx mice developed muscle weakness, irrespective of bedding and diet. When kept on wood shavings and fed a conventional rodent diet, mdx mice showed progressive muscle weakness over the consecutive 200 d, and eventually showed a significant weight loss during the next 200-d observation period. Progression of muscle weakness and weight loss were almost completely prevented in mdx mice that were kept on wheat kernel bedding. In contrast, only incomplete maintenance of muscle strength and body weight was observed in mdx mice kept on wood shavings and fed the alpha-tocopherol-supplemented diet. It is concluded from these experiments that a component of wheat kernels other than alpha-tocopherol is essential to prevent the progression of muscle weakness in mdx mice.