Study: Type 2 narcolepsy is significantly different from type 1

Patients with type 1 narcolepsy have more clinical impairments and distinct functional abnormalities than do patients with type 2 narcolepsy, according to investigators.

Patients with type 2 “do not present with such severe handicaps and are clinically closer to hypersomniac patients than the patients with type 1 narcolepsy,” reported Yu-Shu Huang, MD, of Chang Gung Memorial Hospital and Chang Gung University, Taoyuan City, Taiwan, and associates. The study was published in Neurology.

The researchers used brain scans, neuropsychological tests, and other screening tests to analyze three groups of subjects – 104 patients with Na-1, 29 with Na-2, and a control group of 26 subjects. Depending on the group, 62%-66% of the subjects were men, and the mean age ranged from 19 to 20.

The mean age of onset for the narcolepsy groups was 12-13. Those with Na-1 had higher mean body mass indexes – 27 kg/m² vs. 24 (Na-2) vs. 20 (control), (P = .001).

The patients in both narcolepsy groups showed similar levels of sleepiness, but those with Na-2 had significantly fewer abnormal findings and disturbances.

Patients with Na-2 had significantly fewer sleep-onset REM periods, longer mean sleep latencies, and lower apnea-hypopnea indexes. The human leukocyte antigen DQ-Beta1*0602 was also found less frequently in Na-2 compared to Na-1 (52% vs. 97%, respectively, P less than .001).

PET findings also revealed less impairment in Na-2 compared to Na-1. The researchers noted increased metabolic rate in several brain areas in Na-1, although hypometabolism is more common in some areas in Na-2.

Based on their findings, the authors challenge a previous study of insurance data that suggests patients with both types have similarly poor outcomes over the long term. (PLoS One 2012;7:e33525.)

“In our study,” the authors wrote, “compared to patients with type 2 narcolepsy, patients with type 1 narcolepsy present with much more severe handicaps as early as adolescence. Further studies are needed to clarify the issue.”

The Taiwan Ministry of Science and Technology funded the study. The authors report no relevant disclosures.

SOURCE: Huang Y, et al. March 30, 2018, Neurology. 2018 Mar 30. doi: 10.1212/WNL.0000000000005346.

Patients with type 1 narcolepsy have more clinical impairments and distinct functional abnormalities than do patients with type 2 narcolepsy, according to investigators.

Patients with type 2 “do not present with such severe handicaps and are clinically closer to hypersomniac patients than the patients with type 1 narcolepsy,” reported Yu-Shu Huang, MD, of Chang Gung Memorial Hospital and Chang Gung University, Taoyuan City, Taiwan, and associates. The study was published in Neurology.

The researchers used brain scans, neuropsychological tests, and other screening tests to analyze three groups of subjects – 104 patients with Na-1, 29 with Na-2, and a control group of 26 subjects. Depending on the group, 62%-66% of the subjects were men, and the mean age ranged from 19 to 20.

The mean age of onset for the narcolepsy groups was 12-13. Those with Na-1 had higher mean body mass indexes – 27 kg/m² vs. 24 (Na-2) vs. 20 (control), (P = .001).

The patients in both narcolepsy groups showed similar levels of sleepiness, but those with Na-2 had significantly fewer abnormal findings and disturbances.

Patients with Na-2 had significantly fewer sleep-onset REM periods, longer mean sleep latencies, and lower apnea-hypopnea indexes. The human leukocyte antigen DQ-Beta1*0602 was also found less frequently in Na-2 compared to Na-1 (52% vs. 97%, respectively, P less than .001).

PET findings also revealed less impairment in Na-2 compared to Na-1. The researchers noted increased metabolic rate in several brain areas in Na-1, although hypometabolism is more common in some areas in Na-2.

Based on their findings, the authors challenge a previous study of insurance data that suggests patients with both types have similarly poor outcomes over the long term. (PLoS One 2012;7:e33525.)

“In our study,” the authors wrote, “compared to patients with type 2 narcolepsy, patients with type 1 narcolepsy present with much more severe handicaps as early as adolescence. Further studies are needed to clarify the issue.”

The Taiwan Ministry of Science and Technology funded the study. The authors report no relevant disclosures.

SOURCE: Huang Y, et al. March 30, 2018, Neurology. 2018 Mar 30. doi: 10.1212/WNL.0000000000005346.

Patients with type 1 narcolepsy have more clinical impairments and distinct functional abnormalities than do patients with type 2 narcolepsy, according to investigators.

Patients with type 2 “do not present with such severe handicaps and are clinically closer to hypersomniac patients than the patients with type 1 narcolepsy,” reported Yu-Shu Huang, MD, of Chang Gung Memorial Hospital and Chang Gung University, Taoyuan City, Taiwan, and associates. The study was published in Neurology.

The researchers used brain scans, neuropsychological tests, and other screening tests to analyze three groups of subjects – 104 patients with Na-1, 29 with Na-2, and a control group of 26 subjects. Depending on the group, 62%-66% of the subjects were men, and the mean age ranged from 19 to 20.

The mean age of onset for the narcolepsy groups was 12-13. Those with Na-1 had higher mean body mass indexes – 27 kg/m² vs. 24 (Na-2) vs. 20 (control), (P = .001).

The patients in both narcolepsy groups showed similar levels of sleepiness, but those with Na-2 had significantly fewer abnormal findings and disturbances.

Patients with Na-2 had significantly fewer sleep-onset REM periods, longer mean sleep latencies, and lower apnea-hypopnea indexes. The human leukocyte antigen DQ-Beta1*0602 was also found less frequently in Na-2 compared to Na-1 (52% vs. 97%, respectively, P less than .001).

PET findings also revealed less impairment in Na-2 compared to Na-1. The researchers noted increased metabolic rate in several brain areas in Na-1, although hypometabolism is more common in some areas in Na-2.

Based on their findings, the authors challenge a previous study of insurance data that suggests patients with both types have similarly poor outcomes over the long term. (PLoS One 2012;7:e33525.)

“In our study,” the authors wrote, “compared to patients with type 2 narcolepsy, patients with type 1 narcolepsy present with much more severe handicaps as early as adolescence. Further studies are needed to clarify the issue.”

The Taiwan Ministry of Science and Technology funded the study. The authors report no relevant disclosures.

SOURCE: Huang Y, et al. March 30, 2018, Neurology. 2018 Mar 30. doi: 10.1212/WNL.0000000000005346.