{"doi":"10.1177/155005940103200305","title":"Human Sleep EEG Analysis Using the Correlation Dimension","abstract":"<jats:p>Sleep electroencephalograms (EEG) were analyzed by non-linear analysis. Polysomnography (PSG) of nine healthy male subjects was analyzed and the correlation dimension (D2) was calculated. The D2 characterizes the dynamics of the sleep EEG, estimates the degrees of freedom, and describes the complexity of the signal. The mean D2 decreased from the awake stage to stages 1,2,3 and 4 and increased during rapid eye movement (REM) sleep. The D2 during each REM sleep stage were high and those during each slow wave sleep stage were low, respectively, for each sleep cycle. The mean D2 of the sleep EEG in the second half of the night was significantly higher than those in the first half of the night. Significant changes were also observed during sleep stage 2, but were not seen during REM sleep and sleep stages 3 and 4. The D2 may be a useful method in the analysis of the entire sleep EEG.</jats:p>","journal":"Clinical Electroencephalography","year":2001,"id":40704,"datarank":2.711778809757236,"base_score":3.5553480614894135,"endowment":3.5553480614894135,"self_citation_contribution":0.5333022092234121,"citation_network_contribution":2.178476600533824,"self_endowment_contribution":0.5333022092234121,"citer_contribution":2.178476600533824,"corpus_percentile":null,"corpus_rank":null,"citation_count":34,"citer_count":34,"citers_with_citation_signal":31,"citers_with_endowment":31,"datacite_reuse_total":0,"is_dataset":false,"is_dataset_confidence":null,"is_data_producer":false,"deposit_databanks":null,"is_oa":false,"file_count":0,"downloads":0,"has_version_chain":false,"published_date":null,"fair_score":null,"fair_percentile":null,"algorithm_id":"datarank_citation_only_1hop_v6","ranking_scope":"data_only","authors":[{"id":197296,"name":"Shigeki Madokoro","orcid":null,"position":1,"is_corresponding":false},{"id":197297,"name":"Yuji Wada","orcid":null,"position":2,"is_corresponding":false},{"id":197298,"name":"Kiwamu Misaki","orcid":null,"position":3,"is_corresponding":false},{"id":197299,"name":"Hiroki Nakagawa","orcid":null,"position":4,"is_corresponding":false},{"id":197295,"name":"Toshio Kobayashi","orcid":null,"position":0,"is_corresponding":false}],"reference_count":0,"raw_metadata":{"has_enrichment":true,"base_score":3.5553480614894135,"endowment":3.5553480614894135,"datacite_reuse_total":0,"file_count":0,"downloads":0,"views":0,"has_version_chain":false,"is_dataset":false,"is_oa":false,"pmid":"11512374","pmcid":null,"openalex_id":"https://openalex.org/W41640785","authors":[],"funders":[],"total_grants":0,"fwci":1.0783,"citation_percentile":0.74657912,"influential_citations":0,"citation_trend":[{"year":2012,"count":1},{"year":2014,"count":3},{"year":2018,"count":1},{"year":2021,"count":1},{"year":2022,"count":1},{"year":2024,"count":2},{"year":2025,"count":2}],"oa_status":"closed","license":"https://journals.sagepub.com/page/policies/text-and-data-mining-license","oa_locations":[{"url":"https://journals.sagepub.com/doi/pdf/10.1177/155005940103200305","host_type":"publisher"},{"url":"https://journals.sagepub.com/doi/full-xml/10.1177/155005940103200305","host_type":"publisher"},{"url":"https://doi.org/10.1177/155005940103200305","host_type":"journal"},{"url":"https://pubmed.ncbi.nlm.nih.gov/11512374","host_type":"repository"}],"fields_of_study":["EEG and Brain-Computer Interfaces","Chaos control and synchronization","Neural dynamics and brain function","Psychology","Medicine","Adult","Electroencephalography","Humans","Male","Nonlinear Dynamics","Polysomnography","Sleep Stages","Sleep, REM","Wakefulness"],"mesh_terms":["Adult","Electroencephalography","Humans","Male","Sleep Stages","Sleep, REM","Wakefulness","Polysomnography","Nonlinear Dynamics"],"keywords":["Polysomnography","Sleep (system call)","Electroencephalography","Slow-wave sleep","K-complex","Sleep Stages","Sleep spindle","Audiology","Non-rapid eye movement sleep","Rapid eye movement sleep","Psychology","Eye movement","Sleep onset","Correlation","Delta wave","Medicine","Insomnia","Neuroscience","Mathematics","Psychiatry","Computer science"],"sdg_mappings":[{"sdg_number":0,"sdg_label":"Gender equality"}],"linked_datasets":[],"clinical_trials":[],"software_tools":[],"database_accessions":[],"source":"live","citation_network_status":"fetched"},"created_at":"2026-06-12T12:27:00.377807Z","pmid":null,"pmcid":null,"fwci":null,"citation_percentile":null,"influential_citations":0,"oa_status":null,"license":null,"views":0,"total_file_size_bytes":0,"version_count":0,"fair_f":null,"fair_a":null,"fair_i":null,"fair_r":null,"fair_zscore":null,"fair_rationale":null,"fair_model":null,"fair_agent_version":null,"fair_fulltext_source":null,"fair_has_llm":null,"fair_computed_at":null,"clinical_trials":[],"software_tools":[],"db_accessions":[],"linked_datasets":[],"topics":[]}