The optimization of the targeting of a defined cortical region is a challenge in the current practice of transcranial magnetic stimulation (TMS). The dorsolateral prefrontal cortex (DLPFC) and the ...primary motor cortex (M1) are among the most usual TMS targets, particularly in its “therapeutic” application. This study describes a practical algorithm to determine the anatomical location of the DLPFC and M1 using a three-dimensional (3D) brain reconstruction provided by a TMS-dedicated navigation system from individual magnetic resonance imaging (MRI) data. The coordinates of the right and left DLPFC and M1 were determined in 50 normal brains (100 hemispheres) by five different investigators using a standardized procedure. Inter-rater reliability was good, with 95% limits of agreement ranging between 7 and 16mm for the different coordinates. As expressed in the Talairach space and compared with anatomical or imaging data from the literature, the coordinates of the DLPFC defined by our algorithm corresponded to the junction between BA9 and BA46, while M1 coordinates corresponded to the posterior border of hand representation. Finally, we found an influence of gender and possibly of age on some coordinates on both rostrocaudal and dorsoventral axes. Our algorithm only requires a short training and can be used to provide a reliable targeting of DLPFC and M1 between various TMS investigators. This method, based on an image-guided navigation system using individual MRI data, should be helpful to a variety of TMS studies, especially to standardize the procedure of stimulation in multicenter “therapeutic” studies.
•Correct targeting may increase the therapeutic impact of TMS.•We developed original algorithms to precisely target the DLPFC and M1.•We located these areas in 50 brain MRIs, using a TMS-dedicated navigation system.•We found high inter-rater reliability and anatomical accuracy of our procedure.•Our algorithms can be useful for DLPFC and M1 targeting in TMS practice.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
Background
‘Conventional’ protocols of high‐frequency repetitive transcranial magnetic stimulation (rTMS) delivered to M1 can produce analgesia. Theta burst stimulation (TBS), a novel rTMS paradigm, ...is thought to produce greater changes in M1 excitability than ‘conventional’ protocols. After a preliminary experiment showing no analgesic effect of continuous or intermittent TBS trains (cTBS or iTBS) delivered to M1 as single procedures, we used TBS to prime a subsequent session of ‘conventional’ 10 Hz‐rTMS.
Methods
In 14 patients with chronic refractory neuropathic pain, navigated rTMS was targeted over M1 hand region, contralateral to painful side. Analgesic effects were daily assessed on a visual analogue scale for the week after each 10 Hz‐rTMS session, preceded or not by TBS priming. In an additional experiment, the effects on cortical excitability parameters provided by single‐ and paired‐pulse TMS paradigms were studied.
Results
Pain level was reduced after any type of rTMS procedure compared to baseline, but iTBS priming produced greater analgesia than the other protocols. Regarding motor cortex excitability changes, the analgesic effects were associated with an increase in intracortical inhibition, whatever the type of stimulation, primed or non‐primed.
Conclusions
The present results show that the analgesic effects of ‘conventional’ 10 Hz‐rTMS delivered to M1 can be enhanced by TBS priming, at least using iTBS. Interestingly, the application of cTBS and iTBS did not produce opposite modulations, unlike previously reported in other systems. It remains to be determined whether the interest of TBS priming is to generate a simple additive effect or a more specific process of cortical plasticity.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
Background
Repetitive transcranial magnetic stimulation (rTMS) can relieve neuropathic pain when applied at high frequency (HF: 5–20 Hz) over the primary motor cortex (M1), contralateral to pain ...side. In most studies, rTMS is delivered over the hand motor hot spot (hMHS), whatever pain location. Navigation systems have been developed to guide rTMS targeting, but their value to improve rTMS efficacy remains to be demonstrated.
Objective
To compare the analgesic efficacy of HF‐rTMS targeting the hMHS (non‐navigated procedure) or the M1 representation of the pain region (navigated procedure).
Methods
The analgesic effect of a single session of 10 Hz‐rTMS of M1 was assessed in 66 patients with neuropathic pain of various causes and locations, according to three conditions: sham or active non‐navigated rTMS of the hMHS and active navigated rTMS of the pain region.
Results
Pain was relieved by both active rTMS conditions, and not by sham. Pain location influenced the results: upper or lower limb pain was significantly relieved, but not facial or hemibody pain. Pain relief lasted 1 week only after navigated rTMS, compared to sham.
Conclusion
Navigation may improve HF‐rTMS efficacy in patients with limb pain, whereas targeting remains to be optimized for more diffuse or facial pain.
What does this study add?
To produce analgesic effects, HF‐rTMS should be applied over the precentral cortex contralaterally to the painful side. Although the hMHS is the target normally chosen for stimulation, the optimal target has not been defined yet. Neuronavigational methods have been recently developed; they allow the integration of MRI data and are thought to improve rTMS efficacy.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
Summary Tremor is frequently described in patients with multiple sclerosis (MS) but remains poorly characterized using neurophysiological techniques. Accelerometric (ACC) and electromyographic (EMG) ...recordings were performed in 26 MS patients complaining of clumsiness, associated ( n = 16) or not associated ( n = 10) with visible tremor. Seventeen healthy subjects with physiological tremor (PT) and eight patients with essential tremor (ET) served as controls. Signals were analyzed using non-linear Empirical Mode Decomposition (EMD) and related Hilbert-Huang Transform (HHT), compared to the standard linear spectral analysis using Fast Fourier Transform (FFT). The presence of cerebellar signs and motor deficit was assessed on clinical examination. Using FFT, tremor was found in all patients with ET and 12% of subjects with PT, but in none of the MS patients, even in the presence of visible tremor. In contrast, EMD-HHT analysis of ACC-EMG coupling showed common frequency peaks characterizing tremor related to a central generator in 62.5% of MS patients with visible tremor, 40% of MS patients without visible tremor, 29% of subjects with PT, and all patients with ET. In EMD-HHT analysis, tremor characteristics were similar in subjects with PT and MS patients, regardless of the presence of a visible tremor, but these characteristics clearly differed in patients with ET. A visible tremor in MS patients was associated with more frequent cerebellar signs and less motor deficit at the upper limb. The low-frequency tremor observed in MS patients could therefore originate in lesions of the brainstem (midbrain) or cerebellothalamic circuits, or may correspond to an enhanced PT, partly favored by cerebellar dysfunction and being more visible during movement execution in the absence of concomitant motor deficit.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
Summary Rare cases of demyelinating neuropathy have been described in association with amyotrophic lateral sclerosis (ALS). We report two patients with typical ALS whose initial ...electroneuromyographic (ENMG) presentation could suggest the existence of a process of motor nerve fiber demyelination. However, subsequent ENMG examinations and the fatal course of the disease in a few months rather supported severe ongoing axonal degeneration at the origin of motor nerve conduction abnormalities. Repeated examinations could be required to distinguish between ENMG features of concomitant demyelinating neuropathy and rapidly progressive motor neuron loss in ALS.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
During the past decade, a large amount of work on transcranial magnetic stimulation (TMS) has been performed, including the development of new paradigms of stimulation, the integration of imaging ...data, and the coupling of TMS techniques with electroencephalography or neuroimaging. These accumulating data being difficult to synthesize, several French scientific societies commissioned a group of experts to conduct a comprehensive review of the literature on TMS. This text contains all the consensual findings of the expert group on the mechanisms of action, safety rules and indications of TMS, including repetitive TMS (rTMS). TMS sessions have been conducted in thousands of healthy subjects or patients with various neurological or psychiatric diseases, allowing a better assessment of risks associated with this technique. The number of reported side effects is extremely low, the most serious complication being the occurrence of seizures. In most reported seizures, the stimulation parameters did not follow the previously published recommendations (Wassermann, 1998) 430 and rTMS was associated to medication that could lower the seizure threshold. Recommendations on the safe use of TMS / rTMS were recently updated (Rossi et al., 2009) 348, establishing new limits for stimulation parameters and fixing the contraindications. The recommendations we propose regarding safety are largely based on this previous report with some modifications. By contrast, the issue of therapeutic indications of rTMS has never been addressed before, the present work being the first attempt of a synthesis and expert consensus on this topic. The use of TMS/rTMS is discussed in the context of chronic pain, movement disorders, stroke, epilepsy, tinnitus and psychiatric disorders. There is already a sufficient level of evidence of published data to retain a therapeutic indication of rTMS in clinical practice (grade A) in chronic neuropathic pain, major depressive episodes, and auditory hallucinations. The number of therapeutic indications of rTMS is expected to increase in coming years, in parallel with the optimisation of stimulation parameters.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
Background and purpose
High‐dose steroid administration is the usual treatment of multiple sclerosis (MS) relapse, but it remains to determine whether this treatment may act by changing the ...excitability of cortical circuitry.
Methods
The functional cortical effects of high‐dose steroids in 21 MS patients before and after 3 days of intravenous administration of methylprednisolone (1 g/day) for the treatment of MS relapse were studied. Investigations included various clinical scales Kurtzke Functional System Scale (KFSS), Expanded Disability Status Scale and Fatigue Severity Scale, 10‐m walk and transcranial magnetic stimulation (TMS) tests of cortical excitability resting motor threshold, recruitment curve of motor evoked potentials, short‐interval intracortical inhibition (SICI) and intracortical facilitation (ICF) at various interstimuli intervals (ISIs), cortical silent period and interhemispheric inhibition.
Results
Following steroid administration, clinical improvement was significant for the KFSS pyramidal (motor) and total scores, whilst TMS showed a reduction of SICI (mean and maximum values) and an increase of ICF at 10 ms ISI.
Conclusions
Very rapid functional changes in the excitability of cortical circuits involved in motor control can be induced by steroids, before any process of remyelination or axonal regeneration has time to occur. The net effect of steroids on the balance between intracortical GABAergic inhibition and glutamatergic facilitation was in favour of weaker inhibition or stronger facilitation, which could lead to improving the motor performance in MS patients.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
Abstract Neuromyelitis optica (NMO, also eponymously known as Devic's disease) is an immune‐mediated demyelinating disease of the central nervous system that can lead to significant disability. ...Pediatric NMO is a rare disorder often reported after an infection. The authors report a 16 year-old female patient with pemphigus foliaceus who developed subacute optic neuritis followed by cervical transverse myelitis. Restricted distribution of the lesions in the optic nerve and spinal cord was confirmed by ophthalmological evaluation and magnetic resonance imaging of the brain and spinal cord. She was started on intravenous methylprednisolone and then given a maintenance oral prednisone. Subsequently, she was treated with a nonsteroidal immunosuppressant, mycophenolate mofetil, with a target dose of 1000 mg twice a day. Over the course of months, patient noted significant recovery of previous deficits and resolution of the cervical cord enhancement, expansion and cystic dilatation that was previously seen. This case is noteworthy for being the first patient reported with neuromyelitis optica associated with pemphigus foliaceus.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
Adult Burkitt’s lymphoma emerged as an AIDS-defining condition in the 1980s. We describe a case of HIV-associated adult Burkitt’s lymphoma diagnosed and treated with high-dose chemotherapy in our ...institution, complicated by unusual bilateral renal vein tumour thrombi and tumour lysis syndrome. We believe this unique case highlights the need for early recognition of current and potential complications on staging computed tomography imaging, as well as successful use of a high-dose chemotherapy regimen.
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