Enlargements of somatosensory-evoked potentials in progressive supranuclear palsy

Unilateral Transient Enhanced SEP during Integrated Multiparameter Neurophysiological Monitoring in a Newborn with Symptomatic Seizure

During Integrated Multiparametric Neurophysiological Monitoring (IMNA), a newborn with suspected hypoxia at birth and microhaemorrhagic and ischaemic lesions presented some clonic-tonic episodes with specific EEG patterns characterized by rolandic and temporal spikes and the appearance of a unilateral enhanced Somatosensory Evoked Potential (SEP) (10.45 µv). Since the literature does not seem to describe cases of giant SEP in newborns, in this case report, we will discuss the hypotheses underlying this potential. It could be assumed that the ischaemic and haemorrhagic lesions presented by the newborn may have developed as a result of neurotransmitter balance failure. This may be the origin of the EEG picture, which, consequently, could have triggered a potential with high amplitude.

Cutaneous sensory and autonomic denervation in progressive supranuclear palsy

AIM

Progressive Supranuclear Palsy (PSP) is a progressive neurodegenerative tauopathy characterised by motor, behavioural and cognitive dysfunction. While in the last decade, sensory and autonomic disturbances as well as peripheral nerve involvement are well-recognised in Parkinson's Disease (PD), little is known in this regard for PSP. Herein, we aim to assess peripheral sensory and autonomic nerve involvement in PSP and to characterise possible differences in morpho-functional pattern compared to PD patients.

METHODS

We studied 27 PSP and 33 PD patients without electrophysiological signs of neuropathy, and 33 healthy controls (HC). In addition to motor impairment, evaluated by means of UPDRS-III and the PSP rating scale, all patients underwent clinical, functional and morphological assessment of sensory-autonomic nerves through dedicated questionnaires, sympathetic skin response, dynamic sweat test and skin biopsies. The analysis of cutaneous sensory and autonomic innervation was performed using indirect immunofluorescence and confocal microscopy.

RESULTS

PSP patients displayed a length-dependent loss of sensory and autonomic nerve fibres associated with functional impairment compared to HC and, overall, a more severe picture than in PD patients. The disease severity correlated with the loss of intraepidermal nerve fibre density in the leg of PSP patients (p < 0.05).

CONCLUSION

We demonstrated a length-dependent small fibre pathology in PSP, more severe compared to PD, and paralleling disease severity. Our findings suggest the morphological and functional study of cutaneous nerves as possible biomarkers to monitor disease progression and response to new treatments.

Design and evaluation of tiled parallel coordinate visualization of multichannel EEG data

The field of visualization assists data interpretation in many areas, but does not manage all types of data equally well. This holds, in particular, for time-varying multichannel EEG data. No existing method can successfully visualize simultaneous information from all channels in use at all time steps. To address this problem, a new visualization method is presented based on the parallel coordinate method and making use of a tiled organization. This tiled organization employs a two-dimensional row-column representation, rather than a one-dimensional arrangement in columns as used for classical parallel coordinates. The usefulness of the new method, referred to as tiled parallel coordinates (TPC), is demonstrated by a particular type of EEG data. It can be applied to an arbitrary number of time steps, handling the maximum number of channels currently in use. An extensive user evaluation shows that, for a typical EEG assessment task, data evaluation by the TPC method is faster than by an existing clinical EEG visualization method, without loss of information. The generality of the TPC method makes it widely applicable to other time-varying multivariate data types.

Topographic MN-SSEPs (N18, N20 and N30) might characterize underlying CNS involvements in representative types of cerebral palsy

This study is aimed at constructing the neurophysiological basis for determining the characteristic features of cerebral motor disturbance in representative cerebral palsy (CP) types using topographical S-SEPs technology. Median-nerve stimulated S-SEPs (MN-SSEPs) were examined for 23 patients with four representative types of cerebral palsy: 6 athetotic (including 3 patients due to hypoxic-ischemic encephalopathy (HIE) and 3 to kernicterus), 7 hemiplegic, 5 diplegic and 5 tetraplegic types, and 13 normal controls. In HIE group of athetotic CP, frontal N30 specifically showed severe amplitude reduction or abolishment. In hemiplegic CP, both N20 and N30 on the affected cerebral side tended either to disappear or to be normally evoked at the same time, and their mean amplitudes declined severely. In diplegic CP, the amplitudes of subcortical N18 and parietal N20 were not small but significantly enlarged. N30 amplitude stayed within normal. The reason for this unexpected enlargement of N18 and N20 is unclear, but may be partly due to premature birth which caused abnormally abundant dendritic spine due to absence from perinatal normal spine elimination in the brainstem. In several quadriplegic patients, both N20 and N30 disappeared. The mean amplitude of N30 severely decreased. In conclusion, topographical results of N18, N20 and N30 may basically suggest the underlying involvement of nervous structures in CP according to their representative type.

Observation of unaveraged giant MEG activity from language areas during speech tasks in patients harboring brain lesions very close to essential language areas: expression of brain plasticity in language processing networks?

We describe a series of 12 patients who suffered from lesions adjacent to the classic Broca and Wernicke areas and were examined by magnetoencephalography (MEG) for presurgical language localization while performing a protocol of different language tasks. In these patients very large MEG activity of up to 5pT was observed, which was located not only in the adjacent language processing brain areas but also in more distant areas, which are part of the language processing neuronal network. The high amplitude and the focal spatial extent of this activity allowed MEG source localization from the unaveraged data. In nine patients sources of this high amplitude activity were even found in the homologous language areas on the contralateral, the nondominant side of the brain. The physiological interrelationship of these large MEG changes needs to be investigated in more detail in further studies especially in the context of possible mechanisms for brain plasticity to overcome inhibitory activity of the impaired language area.