Long-term sensory deficit after Guillain-Barré syndrome

In order to document the sensory deficit still present several years after onset of Guillain-Barré syndrome (GBS) and to determine if the sensory residua have a disrupting effect on daily life, 122 patients were asked to cooperate in a neurological examination and to complete a questionnaire three to six years after onset. On functional assessment 84 patients had no or only minor neurological symptoms or signs, 24 patients showed moderate recovery and 14 patients were left with severe residual signs. On neurological examination, residual sensory deficit was found in the arms of 38 % of the patients and in the legs of 66 % of the patients. Sensory disturbance was experienced as moderate to severe in the arms of 27 % of the patients and in the legs of 40 % of the patients. Muscle aches and cramps were still present in 48 %. There was a statistically significant relation between muscle aches and cramps and objective residual sensory deficit but not with residual weakness. Furthermore, in the group of patients with a pure motor GBS, significantly fewer people suffered from muscle aches and cramps than in the remaining patients (p=0.04). Twenty-five percent of patients changed jobs after their illness, and 44% gave up some leisure activities. It can be concluded that many patients still suffer from sensory deficit, and a considerable number experience these as moderately to seriously disruptive, especially in the legs. Muscle aches and cramps seems to be related to sensory rather than motor dysfunction. Received: 22 August 2000, Received in revised form: 29 November 2000, Accepted: 30 December 2000     

Quantitative sensory testing and norepinephrine levels in REM sleep behaviour disorder – a clue to early peripheral autonomic and sensory dysfunction?

Journal of Neurology - Studies have reported autonomic impairment in patients with idiopathic REM sleep behaviour disorder (iRBD), which is considered a prodromal stage of alpha-synucleinopathies....     

Auditory sensory dysfunction in schizophrenia: imprecision or distractibility?

BACKGROUND: Schizophrenia is associated with large effect-size deficits in auditory sensory processing, as reflected in impaired delayed-tone matching performance. The deficit may reflect either impaired sensory precision, which would be indicative of neural dysfunction within auditory sensory (temporal) regions, or of increased distractibility, which would be indicative of impaired prefrontal function. The present study evaluates susceptibility of schizophrenic subjects to same-modality distraction to determine whether patients fit a "bitemporal" or "prefrontal" model of sensory dysfunction. METHODS: Tone-matching ability was evaluated in 15 first-episode patients, 18 outpatients with chronic illness, and 21 patients in long-term residential care, relative to 32 nonpsychiatric controls of a similar age. A staircase procedure determined individual thresholds for attaining criterion level correct performance. RESULTS: Tone-matching thresholds in the absence of distractors were significantly elevated in patients in long-term residential care relative to all other groups (P<.001). The effect size (d) of the difference relative to controls was extremely large (SD, 1.95). Schizophrenic patients, even those with elevated tone-matching thresholds, showed no increased susceptibility to auditory distraction (P =.42). Deficits in tone-matching performance in subjects with chronic illness could not be attributed to medication status or level of symptoms. CONCLUSIONS: These findings suggest that sensory processing dysfunction in schizophrenia is particularly severe in a subgroup of patients who can be considered poor-outcome based on their need for long-term residential treatment. Furthermore, the absence of increased auditory distractibility argues against prefrontal dysfunction as an origin for auditory sensory imprecision in schizophrenia. Arch Gen Psychiatry. 2000;57:1149-1155.     

Auditory sensory memory in schizophrenia: inadequate trace formation?

This study explored duration mismatch negativity reductions observed in individuals with schizophrenia, in particular, the relationship to behavioural measures of temporal discrimination and two event-related potential (ERP) components occurring during the first phase of auditory sensory memory. Twenty-two patients with a DSM-IV and ICD-10 diagnosis of schizophrenia and 25 healthy comparison volunteers participated in a behavioural and an ERP testing session. Both groups performed equivalently on behavioural estimates of filled interval duration discrimination and gap detection. In contrast, electrophysiological measures revealed a significant reduction in patients' duration mismatch negativity and a significant difference in patients for the pattern of N100 facilitation over short stimulus onset asynchronies. Whilst behavioural results indicate intact temporal processing of filled intervals and equal temporal resolution limits in schizophrenia, both ERP measures indicated differences in auditory processing that may be traced to activity occurring during the first 250 ms. Results highlight the possibility of abnormalities in the process of auditory trace formation and temporal summation in schizophrenia.     

How does morphology relate to function in sensory arbors?

Sensory dendrites fall into many different morphological and functional classes. Polymodal nociceptors are one subclass of sensory neurons, which are of particular note owing to their elaborate dendritic arbors. Complex developmental programs are required to form these arbors and there is striking conservation of morphology, function and molecular determinants between vertebrate and invertebrate polymodal nociceptors. Based on these studies, we argue that arbor morphology plays an important role in the function of polymodal nociceptors. Similar associations between form and function might explain the plethora of dendrite morphologies seen among all sensory neurons.     

“Visual sensory trick” in patient with cervical dystonia

Sensory tricks are clinical maneuvers that may partially relieve dystonic contractions. Any clinical maneuver that modulates afferent sensory and efferent motor pathways could be used as a sensory trick in patients with cervical dystonia. Although various sensory tricks have been described to reduce cervical dystonia, little is known about the exact mechanisms by which they operate. We report a case of cervical dystonia that was alleviated through the use of a visual-sensory trick. Our findings suggest that visual stimulation might be an effective sensory trick in cervical dystonia by compensating for a defective sensory system, or because visual pathways might be also affected by sensory interactions in cervical dystonia.     

Pathology and pathogenesis of sensory neuropathy in Friedreich’s ataxia

Friedreich’s ataxia (FRDA) causes a complex neuropathological phenotype with characteristic lesions of dorsal root ganglia (DRG); dorsal spinal roots; dorsal nuclei of Clarke; spinocerebellar and corticospinal tracts; dentate nuclei; and sensory nerves. This report presents a systematic morphological analysis of sural nerves obtained by autopsy of six patients with genetically confirmed FRDA. The outstanding lesion consisted of lack of myelinated fibers whereas axons were present in normal numbers. On cross-sections, only 11% of all class III-β-tubulin-positive axons were myelinated in FRDA, contrasting with 36% in normal control nerves. Despite their paucity, thin myelinated fibers assembled compact sheaths containing the peripheral myelin proteins PMP-22, P₀, and myelin basic protein. The nerves displayed major modifications in Schwann cells that were apparent by laminin 2 and S100α immunocytochemistry. Few S100α-immunoreactive cells remained detectable whereas laminin 2 reaction product was abundant. The normal honeycomb-like distribution of laminin 2 around myelinated fibers was replaced by confluent regions of reaction product that enveloped clusters of closely apposed thin axons. Electron microscopy not only confirmed the lack of myelin but also showed abnormal Schwann cells and axons. Ferritin localized to normal Schwann cell cytoplasm. In the sensory nerves of patients with FRDA, the distribution of this protein strongly resembled laminin 2, but there was no net increase of the total ferritin-reactive area. Ferroportin reaction product occurred in all axons of sural nerves in FRDA, which was at variance with dorsal spinal roots. In the pathogenesis of sensory neuropathy in FRDA, two mechanisms are likely: hypomyelination due to faulty interaction between axons and Schwann cells; and slow axonal degeneration. Neurons of DRG, satellite cells, Schwann cells, and axons of sensory nerves and dorsal spinal roots derive from the neural crest, and hypomyelination in FRDA may be attributed to defects of regulation or migration of shared precursor cells. Sural nerves in FRDA showed no convincing change in ferritin and ferroportin, militating against local iron dysmetabolism. The result stands out in contrast to the previously reported changes in dorsal spinal roots of patients with FRDA.     

Chronic inflammatory demyelinating polyneuropathy or hereditary motor and sensory neuropathy?

The pathological changes generally considered to distinguish chronic inflammatory demyelinating polyneuropathy (CIDP) from hereditary motor and sensory neuropathy (HMSN) are: mononuclear cell infiltrates, prominent endoneurial oedema, and marked fascicle-to-fascicle variability. We evaluated the diagnostic significance of these pathological features which are suggestive of CIDP. Nerve biopsies from 42 dominant HMSN type I cases with a normal disease course were investigated for the occurrence of inflammatory features. A small cluster of mononuclear cells was found in 12% of the cases and marked endoneurial oedema in 21%. Variability in pathology between the fascicles was not observed. The histogram configuration yielded additional information for differential diagnosis. Subsequently, we reviewed the clinical, electrophysiological and morphological features of 18 sporadic cases of chronic progressive demyelinating motor and sensory neuropathy with mainly classic onion bulbs in their nerve biopsies and a disease onset in the first decade. In all these patients DNA investigation for the 17p11.2 duplication was performed. According to the results of the DNA investigation, autosomal dominant HMSN type Ia was diagnosed in eight patients, although in six slight CIDP-positive features were present. A diagnosis was definite or most probable CIDP in eight patients. In two patients no definite diagnosis could be made. Testing for the presence of the 17p11.2 duplication is, therefore, helpful in distinguishing between CIDP and HMSN type I. The diagnosis of CIDP requires careful evaluation of the clinical, electrophysiological and morphological data to avoid false-positive diagnoses of inflammatory disorders.     

Attention and sensory gain control: a peripheral visual process?

Attention-related sensory gain control in human extrastriate cortex is believed to improve the acuity of visual perception. Yet given wide variance in the spatial resolution of vision across the retina, it remains unclear whether sensory gain operates homogenously between foveal and nonfoveal retinotopic locations. To address this issue, we used event-related potentials (ERPs) in a variant of the canonical spatial attention task. Participants were cued to expect targets at either fixation (foveal targets) or at a location several degrees above fixation (parafoveal targets). At both target locations, manual reaction times were shorter for cued relative to uncued targets, indicating that attention was consistently oriented to the cued location. Nevertheless, attention-related increases in sensory-evoked cortical activity were only observed at the parafoveal target location, as measured by the amplitude of the lateral occipital P1 ERP component. A second experiment replicated this data pattern using targets with lower stimulus contrast, indicating that the absence of a P1 effect for foveal targets could not be attributed to a saturated P1 response under higher-contrast stimulus conditions. When considered in light of retinogeniculate projections to cortex showing systematic changes in their physiological organization beginning within a degree of visual angle of the fovea, our findings support the proposal that the strategic functions of visual attention may vary with the retinotopic location involved.     

Acute motor sensory axonal neuropathy associated with Henoch-Schönlein purpura

A 41-year-old man was admitted with progressive tetraparesis with hypoesthesia. He also presented with purpura in both legs. After admission, joint pain, gastrointestinal tract bleeding, and renal dysfunction developed. A nerve conduction study revealed reduced amplitude of the motor and sensory nerve action potential, with normal conduction velocity. A skin biopsy showed leukocytoclastic vasculitis, indicating Henoch-Sch?nlein purpura (HSP). After administration of corticosteroids, the symptom completely disappeared. The present case is the first report in Japan of HSP associated clinically and electrophysiologically with confirmed acute motor sensory axonal neuropathy. Common pathogenesis might have a role for development for two distinct disorders.     

Wartenberg’s migrant sensory neuritis: a prospective follow-up study

Migrant sensory neuropathy (Wartenberg’s migrant sensory neuritis) is characterized by sudden numbness in the distribution of one or multiple cutaneous nerves. To study disease course and outcome, we prospectively followed 12 patients who presented to our tertiary referral neuromuscular outpatient clinic between January 2003 and January 2004. Medical history, neurological, laboratory and electrophysiological examinations were obtained from all patients. All patients were reviewed a second time in 2007, and five had a follow-up electrophysiological examination. At the first visit, 50% described an episode of stretching preceding the sensory complaints. All but three described pain in the affected area before or concomitant with sensory loss. At clinical examination a median of six skin areas were affected, and in 75% this could be confirmed by nerve conduction studies in at least one nerve. Forty-two percent had involvement of the trigeminal nerve. After a mean disease duration of 7.5 years, three patients reported a complete disappearance of sensory complaints and five that the pain had disappeared, but numbness remained. Three patients still had both painful and numb sensory deficits. One patient developed a distal symmetric sensory polyneuropathy. In conclusion, Wartenberg’s sensory neuritis is a distinct, exclusively sensory, neuropathy, marked by pain preceding numbness in affected nerves. An episode of stretching preceding pain is not necessary for the diagnosis. Wartenberg’s sensory neuritis often retains its spotty, exclusively sensory characteristics after long term follow-up.     

Strength–duration properties of sensory and motor axons in alcoholic polyneuropathy

Abstract

Objective: The strength–duration time constant (SDTC) is a measure of axonal excitability and depends on the biophysical properties of the axonal membrane. The strength–duration time constant can provide information about Na⁺ channel function. We aimed to examine changes in the SDTCs of motor and sensory fibers in the median nerves in patients with alcoholic polyneuropathy.

Methods and results: We measured the SDTCs of motor and sensory fibers in 17 patients with alcoholic polyneuropathy (15 men and two women) after stimulating the right median nerve at the wrist. The results were compared with ten healthy age-matched subjects (six men and four women). In patients, the SDTC and rheobase for the motor fibers were 370.8 ± 97.4 μs and 3.9 ± 1.7 mA; for the sensory fibers, the SDTC and rheobase were 464.7 ± 104.3 μs and 3.3 ± 1.9 mA. In controls, the SDTC and rheobase for the motor fibers were 359.3 ± 103.5 μs and 3.5 ± 1.9 mA; for the sensory fibers, the SDTC and rheobase were 478.9 ± 113.9 μs and 2.1 ± 1.5 mA. Sensory fibers had significantly longer SDTCs and lower rheobase than motor fibers in patients and controls. However, when the values of the patients and controls were compared, a statistically significant difference was only found for the rheobase of sensory fibers (p=0.037).

Conclusions: Although alcoholic neuropathy corresponds to the pattern of axonopathy, it did not act on the SDTC of the median nerve, which depends on the biophysical properties of the axonal membrane at the node of Ranvier. The process causing axonal degeneration in alcoholic neuropathy may affect internodal channels other than nodal channels or the Na⁺ –K⁺ ATP pump.     

Motor and sensory demyelinating mononeuropathy multiplex (multifocal motor and sensory demyelinating neuropathy): a separate entity or a variant of chronic inflammatory demyelinating polyneuropathy?

We report 16 patients with motor and sensory demyelinating mononeuropathy multiplex (MSDMM) or multifocal motor and sensory demyelinating neuropathy (MMSDN). These patients had the clinical pattern of motor and sensory mononeuropathy multiplex, electrophysiological evidence of demyelination including conduction block, and segmental demyelination in the sural nerve biopsy. Sixty per cent of patients had high CSF protein. Eighty per cent of patients showed good responsiveness to steroid treatment. Unlike multifocal motor neuropathy (MMN), MSDMM is characterized by a shorter course, sensory deficits and sensory nerve conduction abnormalities, absence of GM1 antibody in most patients tested, and a good response to steroid therapy. We believe that MSDMM represents a variant of chronic inflammatory demyelinating polyneuropathy (CIDP) and an intermediate link between CIDP and MMN.     

Are sensory phenomena present in Sydenham's Chorea? Evaluation of 13 cases

Sydenham's Chorea (SC) is an early complication of rheumatic fever caused by group A beta-hemolytic streptococcal infection that manifests itself with adventitious choreatic movements and behavioral problems. Sensory phenomena are the premonitory sensory experiences that are described prior to tics. Tic disorders and SC share common underlying neurobiological substrates, yet sensory phenomena have not previously been examined in SC. We aimed to explore the presence of sensory phenomena associated with choreatic movements in children with SC. Thirteen SC patients are examined on measures of sensory phenomena using a semi-structured instrument. 10 out of 13 patients described sensory phenomena. Five of the SC patients described sensory phenomena as "between physical and mental". The patients described physical feelings of tension in joints, tingling and trembling sensations on skin. 69 % of them described movements as "completely involuntary". Sites of choreatic movements that were consistently preceded by sensory phenomena were upper and lower extremities, and trunk. Children may have difficulty in articulating sensory phenomena due to the subjective nature of premonitory feelings in SC. We recommend exploring the sensory experiences that might accompany the choreatic movements in children with SC.