Primary visual cortex excitability in migraine: a systematic review with meta-analysis

The objective is to update and extend previous results of a systematic review of the literature with meta-analysis performed to determine the prevalence of phosphenes and the phosphene threshold (PT) values obtained during single-pulse transcranial magnetic stimulation (TMS) in adults with migraine. Both published and unpublished controlled studies measuring PT by single-pulse TMS in adults with migraine with or without aura (MA, MwA) were systematically reviewed. Prevalence of phosphenes and PT values were assessed calculating mean difference (MD) and odds ratio (OR) with 95 % confidence intervals (CI). Fifteen trials (369 migraine patients and 269 controls), were included. Patients with MA had a statistically significant lower PT compared with controls when a circular coil was used (MD: ?22.27, 95 % CI ?33.44 to ?11.10); with a figure-of-eight coil the difference was not statistically significant. There was a significant higher phosphene prevalence in MA compared with controls (OR: 3.57, 95 % CI 1.16–10.94). No significant differences were found either in phosphene reporting between patients with MwA and controls, or in PT values obtained by figure-of-eight coil in subjects with MwA versus controls. In general, these results slightly support the hypothesis of a primary visual cortex hyper-excitability in MA, providing not enough evidence for MwA. A significant heterogeneity across studies probably reflects relevant clinical and methodological heterogeneity.     

Functional evaluation of central cholinergic circuits in patients with Parkinson’s disease and REM sleep behavior disorder: a TMS study

Central cholinergic dysfunction has been reported in patients with Parkinson?s disease (PD) and hallucinations by evaluating short latency afferent inhibition (SAI), a transcranial magnetic stimulation protocol which gives the possibility to test an inhibitory cholinergic circuit in the human brain. REM sleep behavior disorder (RBD) was also found to be associated with cognitive impairment in PD patients. The objective of the study was to assess the cholinergic function, as measured by SAI, in PD patients with RBD (PD-RBD) and PD patients without RBD (PD-nRBD). We applied the SAI technique in 10 PD-RBD patients, in 13 PD-nRBD patients and in 15 age-matched normal controls. All PD patients and control subjects also underwent a comprehensive battery of neuropsychological tests. Mean SAI was significantly reduced in PD-RBD patients when compared with PD-nRBD patients and controls. Neuropsychological examination showed mild cognitive impairment in 9 out of the 10 PD-RBD patients, and in 5 out of the 13 PD-nRBD. SAI values correlated positively with neuropsychological tests measuring episodic verbal memory, executive functions, visuoconstructional and visuoperceptual abilities. Similar to that previously reported in the idiopathic form of RBD, SAI abnormalities suggest a cholinergic dysfunction in PD patients who develop cognitive impairment, and present findings indicate that RBD is an important determinant of MCI in PD.     

Repetitive transcranial magnetic stimulation transiently reduces punding in Parkinson’s disease: a preliminary study

Amongst the impulse-control disorders (ICDs) associated with dopamine-replacement therapy in patients with Parkinson’s disease (PD) is a repetitive, complex, stereotyped behaviour called punding. Disruption of the reciprocal loops between the striatum and structures in the prefrontal cortex (PFC) following dopamine depletion may predispose patients with PD to these behavioural disorders. The purpose of the present study was to assess the effects of repetitive transcranial magnetic stimulation (rTMS) over the dorsolateral PFC (DLPFC) on punding in PD. We used low-frequency (LF) rTMS in four PD patients presenting with punding. Punding was transiently reversed by LF-rTMS over the DLPFC without enhancing motor impairment. The effect was more sustained after right DLPFC rTMS. Therefore, LF-rTMS produced a transient beneficial effect in PD patients with punding, similar to that reported in PD patients with levodopa-induced dyskinesias. rTMS might have therapeutic potential for the treatment of punding and perhaps other ICDs in PD.     

Altered Motor Cortex Excitability to Magnetic Stimulation in Alcohol Withdrawal Syndrome

Background: Alcohol addiction is a complex brain disease caused by alterations in crucial neurotransmitter systems, including gamma‐aminobutyric acid (GABA) and glutamate. These disturbances could be revealed by changes in cortical excitability parameters, as assessed by transcranial magnetic stimulation (TMS). This study was aimed to further investigate the complex pathophysiology of alcohol withdrawal syndrome (AWS). Methods: Motor cortex excitability was examined in 13 subjects with AWS in a mild predelirial state, in 12 chronic alcoholics and in 15 age‐matched control subjects, using a range of TMS protocols. Central motor conduction time, resting and active motor threshold, duration of the cortical silent period, short latency intracortical inhibition (SICI), and intracortical facilitation (ICF) to paired TMS were examined. Results: Intracortical facilitation was significantly increased in the AWS patients when compared with the chronic alcoholics and the control subjects. The other TMS parameters did not differ significantly from the controls. Administration of a single oral dose of the glutamatergic antagonist riluzole in a subgroup of 8 patients significantly reduced ICF; motor threshold and SICI were not affected by riluzole. Conclusion: Transcranial magnetic stimulation shows a selective increase in intracortical facilitation after ethanol withdrawal. Our findings support the theory that altered glutamatergic receptor function plays an important role in the pathogenesis of human alcohol withdrawal. This study provides further physiological evidence that antiglutamatergic approaches represent an efficacious alternative for treating alcohol withdrawal symptoms.     

Demyelinating polyradiculoneuritis following Coxiella burnetti infection (Q fever).

Neurological complications of Coxiella burnetii infection (Q fever) are rare, although the occurrence of headache, paresthesias, and transient focal deficits has been reported. We report the case of a patient with a relapsing demyelinating polyradiculoneuritis as an aftermath of C. burnetti endocarditis and pneumonia.     

MR Atypical Wernicke Encephalopathy Showing Extensive Brain Stem and Diencephalic Involvement

Wernicke encephalopathy (WE) is a serious neurological disorder caused by thiamine (vitamin B1) deficiency. We report a case of atypical and extensive location of abnormal signal lesions on magnetic resonance imaging (MRI) in a man with alcohol abuse with WE. MRI performed on the first hospital day showed signal intensity alterations extending in the whole brain stem and diencephalon; the mismatch between diffusion‐weighted images and apparent diffusion coefficient map was highly suggestive of vasogenic edema. This report further supports the view that WE may represent a spectrum of radiological entities and can have a wide spectrum of manifestations on MRI; thus, clinical features are essential to diagnose it.     

Extra-adrenal Composite Paraganglioma with Ganglioneuroma Component Presenting as a Pancreatic Mass

Paragangliomas may have composite forms in which they combine features of a typical paraganglioma with those of a neural component consisting of either neuroblastoma, ganglioneuroblastoma, or ganglioneuroma. These variants are rare and generally located in the adrenal. Herein, we describe a retroperitoneal, extra-adrenal composite paraganglioma–ganglioneuroma of a 57-year-old woman. Radiological evaluation revealed a nodular mass with apparent pancreatic location, with findings suggestive of an endocrine tumor, yielding the diagnosis of a pancreatic endocrine tumor. At histology the neoplasm, strictly adhering to the external surface of the pancreatic gland but well demarcated, displayed a main central region with typical paraganglioma features and cells arranged in cords and in a nesting “zellballen” pattern, positive for neuroendocrine markers, and a distinct peripheral area consisting of dense bundles of wavy spindled Schwann cells, with scattered ganglionic cells.     

Trigemino-cervical reflex abnormalities in patients with migraine and cluster headache

BACKGROUND: Head pain arises within the trigeminal nociceptive system. Current theories propose that the trigeminal system is intimately involved in the pathogenesis of migraine. Short-latency responses can be recorded in sternocleidomastoid muscles after stimulation of the trigeminal nerve (trigemino-cervical reflex). This brainstem reflex could be a suitable method to evaluate the trigeminal system in migraine and CH. OBJECTIVE: The aim of the present study was to further elucidate the pathophysiology of migraine and cluster headache (CH) with special reference to the involvement of the central trigeminal system in the different forms of primary headache. METHODS: The trigemino-cervical reflex was investigated in 15 healthy subjects, in 15 patients having migraine with aura, in 15 patients with migraine without aura, and in 10 patients with CH. RESULTS: Significant abnormalities were observed in a great number of patients with both types of migraine and CH during the headache attacks, but only in migraine patients during the interictal period. The alterations are bilateral in migraine, unilateral in CH. CONCLUSIONS: Our results further support the relevance of brainstem mechanisms in the pathogenesis of migraine rather than of CH. These data, taken together with that from experimental head pain and functional imaging studies, demonstrate that primary headache syndromes may be distinguished on a functional basis by areas of activation specific to the clinical syndrome.