Many of the motor symptoms of Parkinson disease (PD) can be preceded, sometimes for several years, by non-motor symptoms that include hyposmia, sleep disorders, depression and constipation. These non-motor features appear across the spectrum of patients with PD, including individuals with genetic causes of PD. The neuroanatomical and neuropharmacological bases of non-motor abnormalities in PD remain largely undefined. Here, we discuss recent advances that have helped to establish the presence, severity and effect on the quality of life of non-motor symptoms in PD, and the neuroanatomical and neuropharmacological mechanisms involved. We also discuss the potential for the non-motor features to define a prodrome that may enable the early diagnosis of PD.

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Non-motor features of Parkinson disease.

Computational and Mathematical Methods in Medicine

Background: Revision of the guidelines on the use of skin biopsy in the diagnosis of peripheral neuropathy, published in 2005, has become appropriate owing to publication of more relevant articles. Most of the new studies focused on small fiber neuropathy (SFN), a subtype of neuropathy for which the diagnosis was first developed through skin biopsy examination. This revision focuses on the use of this technique to diagnose SFN.

Methods:  Task force members searched the Medline database from 2005, the year of the publication of the first EFNS guideline, to June 30th, 2009. All pertinent articles were rated according to the EFNS and PNS guidance. After a consensus meeting, the task force members created a manuscript that was subsequently revised by two experts (JML and JVS) in the field of peripheral neuropathy and clinical neurophysiology, who were not previously involved in the use of skin biopsy.

Results and Conclusions:  Distal leg skin biopsy with quantification of the linear density of intraepidermal nerve fibers (IENF), using generally agreed upon counting rules, is a reliable and efficient technique to assess the diagnosis of SFN (Recommendation Level A). Normative reference values are available for bright-field immunohistochemistry (Recommendation Level A) but not yet for confocal immunofluorescence or the blister technique. The morphometric analysis of IENF density, either performed with bright-field or immunofluorescence microscopy, should always refer to normative values matched for age (Recommendation Level A). Newly established laboratories should undergo adequate training in a well-established skin biopsy laboratory and provide their own stratified for age and gender normative values, intra- and interobserver reliability, and interlaboratory agreement. Quality control of the procedure at all levels is mandatory (Good Practice Point). Procedures to quantify subepidermal nerve fibers and autonomic innervated structures, including erector pili muscles, and skin vessels, are under development but need to be confirmed by further studies. Sweat gland innervation can be examined using an unbiased stereologic technique recently proposed (Recommendation Level B).A reduced IENF density is associated with the risk of developing neuropathic pain (Recommendation Level B), but it does not correlate with its intensity. Serial skin biopsies might be useful for detecting early changes of IENF density, which predict the progression of neuropathy, and to assess degeneration and regeneration of IENF (Recommendation Level C). However, further studies are warranted to confirm its potential usefulness as an outcome measure in clinical practice and research. Skin biopsy has not so far been useful for identifying the etiology of SFN. Finally, we emphasize that 3-mm skin biopsy at the ankle is a safe procedure based on the experience of 10 laboratories reporting absence of serious side effects in approximately 35 000 biopsies and a mere 0.19% incidence of non-serious side effects in about 15 years of practice (Good Practice Point).

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European federation of neurological societies/peripheral nerve society guideline on the use of skin biopsy in the diagnosis of small fiber neuropathy. report of a joint task force of the european fe-deration of neurological societies and the peripheral nerve society

Small fibre neuropathy (SFN), a condition dominated by neuropathic pain, is frequently encountered in clinical practise either as prevalent manifestation of more diffuse neuropathy or distinct nosologic entity. Aetiology of SFN includes pre-diabetes status and immune-mediated diseases, though it remains frequently unknown. Due to their physiologic characteristics, small nerve fibres cannot be investigated by routine electrophysiological tests, making the diagnosis particularly difficult. Quantitative sensory testing (QST) to assess the psychophysical thresholds for cold and warm sensations and skin biopsy with quantification of somatic intraepidermal nerve fibres (IENF) have been used to determine the damage to small nerve fibres. Nevertheless, the diagnostic criteria for SFN have not been defined yet and a ‘gold standard’ for clinical practise and research is not available. We screened 486 patients referred to our institutions and collected 124 patients with sensory neuropathy. Among them, we identified 67 patients with pure SFN using a new diagnostic ‘gold standard’, based on the presence of at least two abnormal results at clinical, QST and skin biopsy examination. The diagnosis of SFN was achieved by abnormal clinical and skin biopsy findings in 43.3% of patients, abnormal skin biopsy and QST findings in 37.3% of patients, abnormal clinical and QST findings in 11.9% of patients, whereas 7.5% patients had abnormal results at all the examinations. Skin biopsy showed a diagnostic efficiency of 88.4%, clinical examination of 54.6% and QST of 46.9%. Receiver operating characteristic curve analysis confirmed the significantly higher performance of skin biopsy comparing with QST. However, we found a significant inverse correlation between IENF density and both cold and warm thresholds at the leg. Clinical examination revealed pinprick and thermal hypoesthesia in about 50% patients, and signs of peripheral vascular autonomic dysfunction in about 70% of patients. Spontaneous pain dominated the clinical picture in most SFN patients. Neuropathic pain intensity was more severe in patients with SFN than in patients with large or mixed fibre neuropathy, but there was no significant correlation with IENF density. The aetiology of SFN was initially unknown in 41.8% of patients and at 2-year follow-up a potential cause could be determined in 25% of them. Over the same period, 13% of SFN patients showed the involvement of large nerve fibres, whereas in 45.6% of them the clinical picture did not change. Spontaneous remission of neuropathic pain occurred in 10.9% of SFN patients, while it worsened in 30.4% of them.

The diagnostic criteria for small fibre neuropathy: from symptoms to neuropathology

The concept of consciousness continues to defy definition and elude the grasp of philosophical and scientific efforts to formulate a testable construct that maps to human experience. Severe acquired brain injury results in the dissolution of consciousness, providing a natural model from which key insights about consciousness may be drawn. In the clinical setting, neurologists and neurorehabilitation specialists are called on to discern the level of consciousness in patients who are unable to communicate through word or gesture, and to project outcomes and recommend approaches to treatment. Standards of care are not available to guide clinical decision-making for this population, often leading to inconsistent, inaccurate and inappropriate care. In this Review, we describe the state of the science with regard to clinical management of patients with prolonged disorders of consciousness. We review consciousness-altering pathophysiological mechanisms, specific clinical syndromes, and novel diagnostic and prognostic applications of advanced neuroimaging and electrophysiological procedures. We conclude with a provocative discussion of bioethical and medicolegal issues that are unique to this population and have a profound impact on care, as well as raising questions of broad societal interest.

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Disorders of consciousness after acquired brain injury: the state of the science

Sensory disturbances are part of the clinical picture of Parkinson's disease. Abnormalities in sensory processing, through a basal ganglia involvement, are thought to be responsible for the sensory dysfunction since sensory nerve conduction velocity (NCV) is usually normal. However, NCV does not examine small fibres or terminal endings of large sensory fibres, whereas skin biopsy is more suitable for these purposes. To evaluate peripheral sensory nerves in Parkinson's disease, we studied cutaneous free and encapsulated sensory nerve endings in 18 patients and 30 healthy controls using 3-mm punch biopsies from glabrous and hairy skin. Ten patients had additional skin biopsies from the contralateral side. Further evaluation included NCV and Quantitative Sensory Testing. Parkinson's disease patients showed a significant increase in tactile and thermal thresholds (P < 0.01), a significant reduction in mechanical pain perception (P < 0.01) and significant loss of epidermal nerve fibres (ENFs) and Meissner corpuscles (MCs) (P < 0.01). In patients with bilateral biopsies, loss of pain perception and ENFs was higher on the more affected side (P < 0.01). We found evidence suggesting attempts at counteracting degenerative processes as increased branching, sprouting of nerves and enlargement of the vascular bed. Morphological and functional findings did not correlate with age or disease duration. Disease severity correlated with loss of MCs and reduction in cold perception and pain perception. We demonstrated a peripheral deafferentation in Parkinson's disease that could play a major role in the pathogenesis of the sensory dysfunction.

Sensory deficit in Parkinson's disease: evidence of a cutaneous denervation.

Objectives: Late recovery of awareness in vegetative state (VS) is considered as an exceptional outcome, and has been reported prevalently after traumatic brain injury (TBI). The present prospective study aimed to verify frequency of late recovery (later than 1 year postonset in TBI and 3 months postonset in patients without TBI) of responsiveness and consciousness in traumatic and nontraumatic long-lasting (more than 6 months after onset) VS. Methods: Fifty inpatients with long-lasting VS (36% TBI, 36% hemorrhagic, and 28% anoxic) were enrolled and followed up for a mean of 25.7 months from onset (5 patients for more than 4 years). Level of responsiveness and functional disability were evaluated by means of validated scales (Coma Recovery Scale–Revised and Disability Rating Scale). Results: At the end of the study, 21 patients (42%) had died, 17 patients (34%) were in VS, and 2 patients with TBI (4%) had recovered responsiveness within 12 months postonset. The remaining 10 (20%) patients with TBI and patients without TBI showed late recovery of responsiveness; 6 of them (12%) further progressed to consciousness. Late recovery was significantly associated with younger age and was relatively more frequent in TBI. Functional abilities were severely impaired in all patients. Conclusions: This clinical study demonstrates that late recovery of responsiveness and consciousness is not exceptional in patients with traumatic and nontraumatic VS, although with residual severe disability.

Late recovery after traumatic, anoxic, or hemorrhagic long-lasting vegetative state

Ross syndrome is described as a rare disorder of sweating associated with areflexia and tonic pupil. Since Ross's first description in 1958, ∼40 cases have been described. We assessed the involvement of cutaneous innervation in 12 subjects with Ross syndrome using quantitative sensory testing, sweating assessment and immunohistochemical study of anhidrotic and hyperhidrotic skin. This evaluation was repeated over time in 4 out of 12 subjects. In addition, we enrolled four subjects with Holmes–Adie syndrome (areflexia and tonic pupil) to investigate similarities between the two conditions. We found in Ross patients a complex and progressive involvement of cutaneous sensory and autonomic innervation underlying the impairment of heat production and heat dissipation through both loss of sweating and loss of cutaneous blood flow regulation. In Holmes–Adie subjects we found a mild impairment of sweating without thermoregulatory problems. The persistence of a sudomotor vasoactive intestinal peptide-immunoreactive (VIP-ir) innervation, although deranged and poor, definitely differentiated Holmes–Adie from Ross patients. Ross syndrome is a progressive and complex disorder of thermoregulation difficult to differentiate from the probably pathogenetically related Holmes–Adie syndrome. Sweating assessment and skin biopsy are suitable tools to define a boundary between them. Owing to the large number of Ross patients observed in only 5 years, and to the long and complex medical history of most of them, doubts arise on the effective rarity of this condition, and we warn family doctors and other specialists, besides neurologists, to become aware of this complex disorder.

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Ross syndrome: a rare or a misknown disorder of thermoregulation? A skin innervation study on 12 subjects

Objective: The number of patients in prolonged postanoxic vegetative state (VS) is increasing. However, little information is available about prognostic markers of long-term outcome in patients who remain in VS more than 1 month postonset. The present 2-year prospective clinical study aimed to identify prognostic markers, recorded in the chronic phase, that might be useful for predicting recovery of responsiveness in a cohort of postanoxic VS patients. Methods: We enrolled 43 inpatients with prolonged anoxic VS (23 female; age range 12–83 years). We collected data about medical history, clinical findings, and neurophysiological assessments at study entry (1–6 months postonset), and assessed their relationships with outcome at 24 months postonset; for defining outcome, patients were classified as responsive or unresponsive on the basis of clinical criteria and on Coma Recovery Scale–Revised (CRS-R). Results: Nine patients had recovered responsiveness (but 2 of them died after awakening), whereas 12 patients remained in VS and 22 had died in VS. Functional abilities were severely affected in all responsive survivors. Responsive patients were significantly younger and showed higher CRS-R total score and lower Disability Rating Scale score at study entry than patients who did not recover. All responsive survivors had spared pupillary light reflex and nociceptive response, and paroxysmal sympathetic hyperactivity. Logistic regression analysis showed that the presence of median nerve somatosensory evoked potentials and CRS-R total score ≥6 were significant predictors of recovery of responsiveness. Conclusions: Clinical features and evoked potentials are useful predictors of long-term recovery of responsiveness in patients with prolonged postanoxic VS.

Predictors of recovery of responsiveness in prolonged anoxic vegetative state

Objective: To study small and large fiber pathology in drug-naive and l-dopa–treated patients affected by Parkinson disease (PD) in early phases, before the occurrence of neuropathic electrophysiologic abnormalities. Methods: We enrolled 85 patients with idiopathic PD (male/female 49/36, age 61.3 ± 9.7 years) without electrophysiologic signs of neuropathy, including 48 participants naive to l-dopa treatment. All patients underwent clinical, functional, and morphologic assessment of sensory and autonomic nerves through dedicated questionnaires, quantitative sensory testing, sympathetic skin response, dynamic sweat test, and punch biopsies from glabrous and hairy skin. Sensory and autonomic innervation was visualized with specific antibodies and analyzed by confocal microscopy. Data were compared with those obtained from sex- and age-comparable healthy controls. In 35 patients, skin biopsies were performed bilaterally to evaluate side-to-side differences. Results: Intraepidermal nerve fiber density was lower in patients compared to controls in all the examined sites ( p p p p p Conclusions: Both large and small fiber pathology occurs in the early stages of PD and may account for the sensory and autonomic impairment. l-Dopa affects the 2 populations of fibers differently.

Bernardo Lanzillo

Papers

Sensory deficit in Parkinson's disease: evidence of a cutaneous denervation.

Late recovery after traumatic, anoxic, or hemorrhagic long-lasting vegetative state

Ross syndrome: a rare or a misknown disorder of thermoregulation? A skin innervation study on 12 subjects

Predictors of recovery of responsiveness in prolonged anoxic vegetative state

Loss of cutaneous large and small fibers in naive and l-dopa–treated PD patients