Nociceptive inputs transmission in Huntington's disease: a study by laser evoked potentials.

The aim of the present study was to evaluate pain perception and evoked responses by laser stimuli (LEPs) in mild not demented Huntington's Disease (HD) patients. Twenty-eight HD patients and 30 control subjects were selected. LEPs were obtained by four scalp electrodes, (Fz, Cz, referred to the nasion; T3, T4, referred to Fz), stimulating the dorsum of both hands. All patients were also evaluated by somatosensory evoked potentials (SEPs) by median nerve stimulation. Only 3 patients referred pain of arthralgic type. Laser pain perception was similar between HD patients and controls. An abnormal N2, P2 and N1 latency increase was evident in the majority of HD patients. LEPs features were similar between patients taking and not taking neuroleptics. The N2 and P2 latencies, showed a negative correlation with functional score and Mini Mental State Examination, and a positive correlation with the severity of hyperkinetic movements. A delay in nociceptive input processing emerged in HD, concurring with the main features of the disease, in absence of clinical evidence of abnormalities in pain perception. The dysfunction of pain signals transmission in HD may induce sub-clinical changes of sensory functions, which may probably interfere with sensory-motor integration and contribute to functional impairment.

Fibromyalgia comorbidity in primary headaches.

Fibromyalgia syndrome (FMS) is a chronic pain condition of unknown aetiology characterized by diffuse pain and tenderness at tender points. The aim of the study was to assess the prevalence and clinical features of FMS in the different forms of primary headaches, in a tertiary headache centre. Primary headache patients (n = 217) were selected and submitted to the Total Tenderness Score, anxiety and depression scales, Migraine Disability Assessment, allodynia questionnaire, Short Form 36 Health Survey and the Medical Outcomes Study-Sleep Scale. In patients with FMS, the Multidimensional Assessment of Fatigue, the Pain Visual Analog Scale, the Manual Tender Point Survey and the Fibromyalgia Impact Questionnaire were employed. FMS was present in 36.4% of patients and prevailed significantly in tension-type headache and in patients with higher headache frequency. Headache frequency, pericranial muscle tenderness, anxiety and sleep inadequacy were especially associated with FMS comorbidity. In the FMS patients, fatigue and pain at tender points were significantly correlated with headache frequency. FMS seems increasingly prevalent with increased headache frequency, for the facilitation of central sensitization phenomena favoured by anxiety and sleep disturbances.

Central sensitisation phenomena in primary headaches: overview of a preventive therapeutic approach.

Central sensitisation phenomena have been well recognized in the development of migraine attacks and tension type headache. It is also known that headache frequency is related to sensitization. Though some studies have focused on the effects of symptomatic treatment on allodynia, few reports have described the action of preventive agents on the facilitating factors for central sensitisation. In this study we aim to review the factors concurrent with an increase in central sensitisation, in view of the choice of preventive agents for primary headaches. Central sensitisation phenomena are increased in pain syndromes with psycho-pathological co-morbidities. For instance, sleep disorders are a frequent symptom in headache, prevailing in chronic forms and in patients with psychiatric comorbidity. Sleep deprivation is also a factor producing hyperalgesic changes. It is known that symptoms attributable to central sensitization are diffusely pronounced in fibromyalgic (FMS) patients, and that FMS co-morbidity is frequent in primary headaches and associated with higher frequency and poorer quality of life. We report our preliminary experience in a group of 20 chronic migraine patients, treated with duloxetine 60 mg/die vs a self-management program including stretching (relaxation training) and exercise (cervical-dorsal flexion and rotation) to decrease strength and flexibility of muscles of cervical and dorsal spine headache patients. Both the treatments were effective on headache frequency and pericranial tenderness, although FMS comorbidity significantly reduced their efficacy on migraine and quality of life. The whole spectrum of action of pharmacological and non pharmacological treatments on central sensitisation mechanisms, and on their facilitating factors, should be taken into account for the best preventive therapeutic approach of primary headaches.

Effects of the remote C fibres stimulation induced by capsaicin on the blink reflex in chronic migraine.

The aim of this study was to test the function of the diffuse noxious inhibitory control system (DNIC) in chronic and episodic migraine, exploring the blink reflex (BR) modifications induced by topical application of capsaicin on the hand. We evaluated 11 migraine without aura (MA) and nine chronic migraine (CM) patients during the not symptomatic phase; they were compared with 14 non-headache subjects (N). The BR was elicited by weak electrical stimuli delivered to the right supraorbital nerve; it was obtained 10 min and 20 min after the application of 1 ml of 3% capsaicin in a cream base (Teofarma) on the skin of the dorsum of the right hand, and 60 min after capsaicin removal. The subjective pain sensation induced by capsaicin was significantly increased in CM with respect to both MA patients and normal subjects; the R2 area was increased in CM patients during capsaicin application, with respect to controls and MA patients, who did not exhibit any reflex alterations. These results may suggest a failure of DNIC and a disturbed control of the trigeminal reflex at the central level, linked with migraine frequency.

Effects of amitriptyline and intra-oral device appliance on clinical and laser-evoked potentials features in chronic tension-type headache.

In the present study, we examined clinical and laser-evoked potentials (LEP) features in two groups of chronic tension-type headache (CTTH) patients treated with two different approaches: intra-oral appliance of prosthesis, aiming to reduce muscular tenderness, and 10 mg daily amitriptyline. Eighteen patients suffering from CTTH (IHS, 2004) participated in the study. We performed a basal evaluation of clinical features and LEPs in all patients (T0) vs. 12 age- and sex-matched controls; successively, patients were randomly assigned to a two-month treatment by amitriptyline or intra-oral device appliance. The later LEPs, especially the P2 component, were significantly increased in amplitude in the CTTH group. Both the intra-oral prosthesis and amitriptyline significantly reduced headache frequency. Total Tenderness Score was significantly reduced in the group treated by the prosthesis. The amplitude of P2 response elicited by stimulation of pericranial zones showed a reduction after amitriptyline treatment. The results of this study may confirm that pericranial tenderness is primarily a phenomenon initiating a self-perpetuating circuit, favoured by central sensitisation at the level of the cortical nociceptive areas devoted to the attentive and emotive compounds of pain. Both the interventions at the peripheral and central levels may interrupt this reverberating circuit, improving the outcome of headache.