Muscle atonia index during multiple sleep latency test: A possible marker to differentiate narcolepsy from other hypersomnias

OBJECTIVE

The complexity and delay of the diagnosis of narcolepsy require several diagnostic tests and invasive procedures such as lumbar puncture. Our study aimed to determine the changes in muscle tone (atonia index, AI) at different levels of vigilance during the entire multiple sleep latency test (MSLT) and each nap in people with narcolepsy type 1 (NT1) and 2 (NT2) compared with other hypersomnias and its potential diagnostic value.

METHODS

Twenty-nine patients with NT1 (11 M 18F, mean age 34.9 years, SD 16.8) and sixteen with NT2 (10 M 6F, mean age 39 years, SD 11.8) and 20 controls with other hypersomnias (10 M, 10F mean age 45.1 years, SD 15.1) were recruited. AI was evaluated at different levels of vigilance (Wake and REM sleep) in each nap and throughout the MSLT of each group. The validity of AI in identifying patients with narcolepsy (NT1 and NT2) was analyzed using receiver operating characteristic (ROC) curves.

RESULTS

AI during wakefulness (WAI) was significantly higher in the narcolepsy groups (NT1 and NT2 p < 0.001) compared to the hypersomniac group. AI during REM sleep (RAI) (p = 0.03) and WAI in nap with sudden onsets of REM sleep periods (SOREMP) (p = 0.001) were lower in NT1 than in NT2. The ROC curves showed high AUC values for WAI (NT1 0.88; Best Cut-off > 0.57, Sensitivity 79.3 % Specificity 90 %; NT2 0.89 Best Cut-off > 0.67 Sensitivity 87.5 % Specificity 95 %; NT1 and NT2 0.88 Best Cut-off > 0.57 Sensitivity 82.2 % Specificity 90 %) in discriminating subjects suffering from other hypersomnias. RAI and WAI in nap with SOREMP showed a poor AUC value (RAI AUC: 0.7 Best cutoff 0.7 Sensitivity 50 % Specificity 87.5 %; WAI in nap before SOREMP AUC: 0.66, Best cut-off < 0.82 sensitivity 61.9 % and specificity 67.35 %) differentiating NT1 and NT2.

CONCLUSIONS

WAI may represent an encouraging electrophysiological marker of narcolepsy and suggests a vulnerable tendency to dissociative wake / sleep dysregulation lacking in other forms of hypersomnia.

SIGNIFICANCE

AI during wakefulness may help distinguish between narcolepsy and other hypersomnias.

Improvements in metabolic abnormalities among overweight schizophrenia and bipolar disorder patients

PURPOSE

As weight-gain and metabolic abnormalities during treatment with psychotropic drugs are of great concern, we evaluated effects of psycho-education and medical monitoring on metabolic changes among severely mentally ill patients.

MATERIALS AND METHODS

During repeated, systematic psycho-education about general health among 66 consecutive patients diagnosed with DSM-IV-TR schizophrenia (n=33) or type-I bipolar disorder (n=33), we evaluated (at intake 1, 2, 3, and 6 months) clinical psychiatric status, treatments and doses, recorded physiological parameters, and assessed attitudes about medication.

RESULTS

At intake, patients with schizophrenia vs bipolar disorder were receiving 3-7 times more psychotropic medication, with 14% higher initial body-mass index (BMI: 29.1 vs 25.6 kg/m²), 12 times more obesity, and significantly higher serum lipid concentrations. During 6-months follow-up, among bipolar disorder patients, polytherapy and serum lipid concentrations declined more than among schizophrenia patients (e.g., total cholesterol+triglycerides, by 3.21 vs 1.75%/month). BMI remained stable. Declining lipid levels were associated with older age, bipolar disorder, being unemployed, higher antipsychotic doses, and lower initial BPRS scores (all P ≤ 0.001).

CONCLUSIONS

Psychotropic treatments were more complex, and metabolic measures more abnormal among bipolar disorder than schizophrenia patients. Intensive psycho-education, clinical monitoring, and encouragement of weight-control for six months were associated with improvements in metabolic measures (but not to BMI), and more realistic attitudes about medication.

Sleep disorders in adult-onset myotonic dystrophy type 1: a controlled polysomnographic study

BACKGROUND

  Sleep disturbances and excessive daytime somnolence are common and disabling features in adult-onset myotonic dystrophy type 1 (DM1).

METHODS

  Our study used questionnaires, ambulatory polysomnography and the multiple sleep latency test to evaluate sleep-wake cycle and daytime sleepiness in unselected adult-onset DM1 patients. We recruited 18 patients affected by adult-onset DM1 and 18 matched controls.

RESULTS

  Sleep efficiency was <90% in 16/18 patients, and it was significantly reduced when compared with controls. Reduced sleep efficiency was associated with abnormal respiratory events (5/18 patients) and/or periodic limb movements (11/18 patients). The Periodic Limb Movement Index was significantly increased in DM1 versus controls. A significantly lower mean MSLT sleep latency was detected in DM1 versus controls, but it did not reach pathological levels.

CONCLUSIONS

  Our controlled study demonstrated sleep alterations in unselected consecutive DM1 patients. Periodic limb movements in sleep are commonly associated with sleep disturbance in adult-onset DM1, and it may represent a marker of CNS neurodegenerative processes in DM1.