Evaluation of a Patient-Specific Index as an outcome measure for physiotherapy in Parkinson's disease

AIM

The aim of this paper was to develop and evaluate a patient-specific index for physiotherapy in Parkinson's disease (PSI-PD).

METHODS

In the PSI-PD, patients 1) select problematic activities out of a predefined list, with one self-report item; 2) rank selected items in order of importance; and 3) rate severity for each ranked item. To examine test-retest reliability, a cohort of patients was asked to complete the PSI-PD twice. Afterwards, validity was evaluated using a telephone interview.

RESULTS

The PSI-PD was completed twice by 81 patients. Test-retest agreement for the selection of activity limitations was 73% to 94%. Items ranked by patients were categorized into domains, of which gait, transfers and dexterity were rated most frequently (41%-70%). Test-retest agreement for ranked domains ranged from 74% to 82%. Interviews confirmed that the PSI-PD reliably identified problem areas.

CONCLUSIONS

The PSI-PD is a relevant, reliable and valid instrument to identify limitations in everyday activities that are important for both PD patients and physiotherapists.

Quality indicators for physiotherapy in Parkinson's disease

AIM

The aim of this study was to develop quality indicators for physiotherapy in Parkinson's disease (PD) according to international criteria.

METHODS

Indicators were based on an evidence-based guideline for physiotherapy in PD. Guideline recommendations were transformed into indicators and rated for their relevance by an expert panel. Relevant indicators were incorporated into a questionnaire termed ''Quality Indicators for Physiotherapy in PD'' (QIP-PD). The QIP-PD was piloted among 105 physiotherapists. The adjusted version was evaluated in 46 physiotherapists with specific expertise in PD and in 795 general physiotherapists. The following clinimetric aspects of the QIP-PD were tested: completeness of answers, response distribution, internal consistency, and discriminative power. The reliability of the QIP-PD was evaluated by interviews among a randomly selected cohort of 32 PD experts and 32 general physiotherapists.

RESULTS

The expert panel selected 16 indicators, which were transformed into an adjusted 17-item QIP-PD. The adjusted QIP-PD was completed by 41 expert physiotherapists and 286 general physiotherapists. Comple-teness of item scores ranged from 95-98%. Six items were excluded from the final analyses as they showed ceiling effect among both groups, or lacked discriminative power. The total QIP-PD score for the 11 items was significantly higher for expert physiotherapists (35.1+/-4.2) compared to general physiotherapists (22.2+/-7.7; P=0.01). Internal consistency was good (Crohnbach's alpha 0.84). QIP-PD scores of therapists and interviewers (correlated using Intraclass Correlations Coefficients) ranged from 0.63 to 0.75.

CONCLUSIONS

The QIP-PD is a relevant, feasible, valid, discriminative and reliable instrument to measure adherence to guidelines for physiotherapy in PD. In addition, the results underscore that quality improvement interventions for physiotherapy in PD are needed, as guideline adherence is suboptimal in physiotherapists without specific PD expertise.

Manipulation of skin temperature improves nocturnal sleep in narcolepsy

OBJECTIVE

Besides excessive daytime sleepiness, disturbed nocturnal sleep is a major complaint of patients with narcolepsy. Previously, alterations in skin temperature regulation in narcoleptic patients have been shown to be related to increased sleepiness. This study tests the hypothesis that direct control of nocturnal skin temperature might be applied to improve the disturbed sleep of narcoleptic patients.

METHODS

Participants were eight patients (five males) diagnosed as having narcolepsy with cataplexy according to the ICSD-2 criteria, mean (SD) age 28.6 (6.4) years, range 18-35 years. During two nights, sleep was recorded polysomnographically while proximal and distal skin temperature were manipulated using a comfortable thermosuit that induced skin temperature to cycle slowly with an amplitude of only 0.4 degrees C within the comfortable range normally observed during sleep. Logistic regression was used to evaluate the effect of skin temperature manipulation on the probability of occurrence of different sleep stages and nocturnal wakefulness.

RESULTS

Proximal skin warming significantly suppressed wakefulness and enhanced slow wave sleep (SWS). In contrast, distal skin warming enhanced wakefulness and stage 1 sleep at the cost of SWS and REM sleep. The optimal combination of proximal skin warming and distal skin cooling led to a 160% increase in SWS, a 50% increase in REM sleep and a 68% decrease in wakefulness, compared with the least beneficial combination of proximal skin cooling and distal skin warming.

INTERPRETATION

Subtle skin temperature manipulations under controlled conditions significantly improved the typical nocturnal sleep problems in narcolepsy.

[Narcolepsy: a new perspective on diagnosis and treatment]

The 5 classic symptoms of narcolepsy are excessive daytime sleepiness, cataplexy, sleep paralysis, hypnagogic hallucinations and disturbed nocturnal sleep. The presence of cataplexy is strongly associated with a deficiency of the neuropeptide hypocretin. This discovery has led to new diagnostic subclassifications: narcolepsy without cataplexy, which can be demonstrated by a multiple sleep latency test, and narcolepsy with cataplexy, which can be confirmed with a multiple sleep latency test or a cerebrospinal fluid deficiency of hypocretin I. Various treatment options are available, including psychostimulants and gamma hydroxybuterate.

Symptomatic distal myopathy with cardiomyopathy due to a MYH7 mutation

Mutations in the myosin heavy chain gene (MYH7) can cause several distinct phenotypes depending on the location of the mutation: hypertrophic cardiomyopathy (several exons), myosin storage myopathy (exon 37/39) or Laing distal myopathy (exons 32-36). Here, we describe a unique combination of hypertrophic cardiomyopathy and hypertrophic distal myopathy in a family with a MYH7 Val606Met mutation (exon 16).

Convergence of circadian and sleep regulatory mechanisms on hypocretin-1

Hypocretin is a potential regulator of sleep and wakefulness and its levels fluctuate with the day-night cycle with high levels during the animal's activity period. Whether the daily fluctuations are driven endogenously or by external light cycles is unknown. We investigated the circadian and homeostatic regulation of hypocretin in the absence of environmental light cycles. To this purpose we performed repetitive samplings of cerebrospinal fluid in rats through implanted microcannulas in the cisterna magna and determined hypocretin-1 levels by radioimmunoassay. These experiments were also performed in rats that received a lesion of the suprachiasmatic nucleus (SCN), a major pacemaker for circadian rhythms in mammals. The results showed sustained rhythmicity of hypocretin in constant dim red light in control animals. SCN-lesioned animals showed no circadian rhythms in hypocretin and mean hypocretin levels were remarkably low. The results indicate that the SCN is indispensable for rhythmicity in hypocretin and induces a daily increase in hypocretin levels during the animal's active phase. Additional sleep deprivation experiments were carried out to investigate homeostatic regulation of hypocretin. Hypocretin levels increased in response to sleep deprivation in both control and SCN-lesioned animals, demonstrating that sleep homeostatic control of hypocretin occurs independently from the SCN. Our data indicate that the circadian pacemaker of the SCN and sleep homeostatic mechanisms converge on one single sleep regulatory substance.

Pulsatile LH release is diminished, whereas FSH secretion is normal, in hypocretin-deficient narcoleptic men

Hypocretin (orexin) peptides are involved in the regulation of energy balance and pituitary hormone release. Narcolepsy is a sleep disorder characterized by disruption of hypocretin neurotransmission. Pituitary LH secretion is diminished in hypocretin-deficient animal models, and intracerebroventricular administration of hypocretin-1 activates the hypothalamo-pituitary-gonadal axis in rats. We evaluated whether hypocretin deficiency affects gonadotropin release in humans. To this end, we deconvolved 24-h serum concentrations of LH and FSH in seven hypocretin-deficient narcoleptic males (N) and seven controls (C) matched for age, body mass index, and sex. Basal plasma concentrations of testosterone, estradiol, and sex hormone-binding globulin were similar in both groups. Mean 24-h LH concentration was significantly lower in narcolepsy patients [3.0 +/- 0.4 (N) vs. 4.2 +/- 0.3 (C) U/l, P = 0.01], which was primarily due to a reduction of pulsatile LH secretion [23.5 +/- 1.6 (N) vs. 34.3 +/- 4.9 (C) U.l(-1).24 h(-1), P = 0.02]. The orderliness of LH and FSH secretion, quantitated by the approximate entropy statistic, was greater in patients than in controls. In contrast, all other features of FSH release were similar in narcoleptic and control groups. Also, LH and FSH secretions in response to intravenous administration of 100 microg of GnRH were similar in patients and controls. These data indicate that endogenous hypocretins are involved in the regulation of the hypothalamo-pituitary-gonadal axis activity in humans. In particular, reduced LH release in the face of normal pituitary responsivity to GnRH stimulation in narcoleptic men suggests that hypocretins promote endogenous GnRH secretion.

Hypocretin-1 CSF levels in anti-Ma2 associated encephalitis

Idiopathic narcolepsy is associated with deficient hypocretin transmission. Narcoleptic symptoms have recently been described in paraneoplastic encephalitis with anti-Ma2 antibodies. The authors measured CSF hypocretin-1 levels in six patients with anti-Ma2 encephalitis, and screened for anti-Ma antibodies in patients with idiopathic narcolepsy. Anti-Ma autoantibodies were not detected in patients with idiopathic narcolepsy. Four patients with anti-Ma2 encephalitis had excessive daytime sleepiness; hypocretin-1 was not detectable in their cerebrospinal fluid, suggesting an immune-mediated hypocretin dysfunction.

CSF hypocretin levels in Guillain-Barre syndrome and other inflammatory neuropathies

CSF hypocretin-1 was measured in 28 Guillain-Barré syndrome (GBS), 12 Miller-Fisher syndrome, 12 chronic inflammatory demyelinating polyneuropathy (CIDP), and 48 control subjects. Seven GBS subjects had undetectably low hypocretin-1 levels (<100 pg/mL). Hypocretin-1 levels were moderately reduced in an additional 11 GBS, 5 Miller-Fisher syndrome, and 1 CIDP subject. Low levels in GBS occurred early in the disease and were associated with upper CNS level abnormalities.

Dynamics of the pituitary-adrenal ensemble in hypocretin-deficient narcoleptic humans: blunted basal adrenocorticotropin release and evidence for normal time-keeping by the master pacemaker

Narcolepsy is a sleep disorder caused by disruption of hypocretin (orexin) neurotransmission. It has been suggested that anomalous timing by the biological clock contributes to the symptomatology. Hypocretins stimulate the pituitary-adrenal (PA) axis in rodents. We explored whether hypocretin deficiency disrupts circadian timing and blunts PA hormone release. We deconvolved 24-h plasma profiles of ACTH and cortisol, and determined their circadian rhythm by cosinor analysis in seven hypocretin-deficient narcoleptic males and seven matched controls. Basal and total ACTH production were blunted in narcoleptics [310 +/- 86 vs. 760 +/-160 ng/liter.24 h (P = 0.02) and 920 +/- 147 vs. 1460 +/- 220 ng/liter.24 h (P = 0.04), respectively], whereas pulsatile release did not differ between groups. In contrast, basal, pulsatile and total cortisol secretion were similar in both groups. The cross-approximate entropy of the joint ACTH/cortisol time series was higher in narcoleptics (1.26 +/- 0.07 vs. 1.07 +/- 0.04; P = 0.04), reflecting reduced secretory process regularity. The acrophases of both ACTH and cortisol occurred at similar clock times (approximately 0830 h) in patients and controls, which supports the idea that the master pacemaker is intact in narcolepsy. The reduced (basal) ACTH secretion and the diminished secretory process regularity of the ACTH/cortisol ensemble conjointly suggest that hypocretin deficiency induces changes in the interplay between PA hormones.

Reduction of plasma leptin levels and loss of its circadian rhythmicity in hypocretin (orexin)-deficient narcoleptic humans

Recent observations have implicated hypocretin deficiency in the pathogenesis of narcolepsy. Hypocretin neurotransmission also affects energy balance, and narcoleptic patients tend to become obese. Because hypocretins appear to have important neuroendocrine effects, we hypothesized that the neuroendocrine systems that regulate energy balance might be distinctly set in narcolepsy. As leptin is a pivotal part of these systems, we explored the 24-h plasma leptin (20-min sampling interval) concentration profile in six narcoleptic males and six normal controls, matched for age, sex, body mass index, waist/hip ratio, and fat mass. We thus demonstrated a reduction of the mean 24-h leptin concentration in narcoleptics to 52% of that in controls (5.9 microg/liter in narcolepsy vs. 11.4 microg/liter in controls; P < 0.05). Further, a nocturnal acrophase (clock time of the highest concentration), which is typical of normal leptin secretion, was observed in controls (mean, 2335 h; 95% confidence interval, 2105-0205 h), but not in narcoleptic patients. The mechanisms that potentially disturb the circadian rhythm of leptin levels in hypocretin-deficient narcoleptic humans include anomalies of the sleep-wake cycle and/or disruption of the circadian distribution of autonomic activity. As leptin deficiency clearly leads to morbid obesity in experimental animals and humans, we infer that the observed reduction of plasma leptin levels may predispose narcoleptic humans to weight gain.

[Hypocretin (orexin) deficiency in narcolepsy-cataplexy]

A mutation in the HCRT locus was proved in 18-yrs old male suffering from narcolepsy-cataplexy. He has demonstrated cataplectic attacks (brief spells of head dropping provoked by laughter) as well as imperative sleep in spells of several minutes up to one hour since the age of six months. He has suffered from severe bulimia since five years; later hypnagogic hallucinations, sleep paralysis and unquiet nocturnal sleep accompanied by periodic limb movements appeared. Symptoms are partially controlled with methylphenidate and either imipramine, clomipramine or fluoxetine. Periodic leg movements poorly responded to L-DOPA and clonazepam treatment. He is HLA-DQB1*0602 negative. Repeated MSLT (over 16 years followed-up period) showed extremely short latency with predominant SOREMPs and also nocturnal PSG recordings revealed fragmented sleep with SOREMPs. This case report demonstrates that hypocretin (orexin) mutations in human can produce the full narcolepsy phenotype and validates data recently reported in dog and mouse models suggesting a role for hypocretin (orexin) in the pathophysiology of narcolepsy and the regulation of REM sleep.

Dynamic posturography using a new movable multidirectional platform driven by gravity

Human upright balance control can be quantified using movable platforms driven by servo-controlled torque motors (dynamic posturography). We introduce a new movable platform driven by the force of gravity acting upon the platform and the subject standing on it. The platform consists of a 1 m2 metal plate, supported at each of its four corners by a cable and two magnets. Sudden release of the magnets on three sides of the platform (leaving one side attached) induces rotational perturbations in either the pitch or roll plane. Release of all magnets causes a purely vertical displacement. By varying the slack in the supporting cables, the platform can generate small (0.5 degrees ) to very destabilising (19 degrees ) rotations. Experiments in healthy subjects showed that the platform generated standardised and reproducible perturbations. The peak rotation velocity well exceeded the threshold required to elicit postural responses in the leg muscles. Onset latencies were comparable to those evoked by torque motor-driven platforms. Randomly mixed multidirectional perturbations of large amplitude forced the subject to use compensatory steps (easily possible on the large support surface), with little confounding influence of habituation. We conclude that this gravity-driven multidirectional platform provides a useful and versatile tool for dynamic posturography.

CSF hypocretin/orexin levels in narcolepsy and other neurological conditions

OBJECTIVE

To examine the specificity of low CSF hypocretin-1 levels in narcolepsy and explore the potential role of hypocretins in other neurologic disorders.

METHODS

A method to measure hypocretin-1 in 100 microL of crude CSF sample was established and validated. CSF hypocretin-1 was measured in 42 narcolepsy patients (ages 16-70 years), 48 healthy controls (ages 22-77 years,) and 235 patients with various other neurologic conditions (ages 0-85 years).

RESULTS

As previously reported, CSF hypocretin-1 levels were undetectably low (<100 pg/mL) in 37 of 42 narcolepsy subjects. Hypocretin-1 levels were detectable in all controls (224-653 pg/mL) and all neurologic patients (117-720 pg/mL), with the exception of three patients with Guillain-Barré syndrome (GBS). Hypocretin-1 was within the control range in most neurologic patients tested, including patients with AD, PD, and MS. Low but detectable levels (100-194 pg/mL) were found in a subset of patients with acute lymphocytic leukemia, intracranial tumors, craniocerebral trauma, CNS infections, and GBS.

CONCLUSIONS

Undetectable CSF hypocretin-1 levels are highly specific to narcolepsy and rare cases of GBS. Measuring hypocretin-1 levels in the CSF of patients suspected of narcolepsy is a useful diagnostic procedure. Low hypocretin levels are also observed in a large range of neurologic conditions, most strikingly in subjects with head trauma. These alterations may reflect focal lesions in the hypothalamus, destruction of the blood brain barrier, or transient or chronic hypofunction of the hypothalamus. Future research in this area is needed to establish functional significance.