{"doi":"10.1002/mds.29362","title":"Redefining Bradykinesia","abstract":"Recognizing and characterizing bradykinesia is a critical issue in movement disorders. Bradykinesia is the core symptom for the definition of parkinsonism and for the diagnosis of Parkinson's disease (PD) and atypical parkinsonism (AP).1-7 To some extent, however, the debate on the terminology and definition of bradykinesia has never been settled.8, 9 Bradykinesia literally means slowness of movement. However, the term is still used interchangeably to indicate low amplitude movement (hypokinesia) or no movement (akinesia),10 and it is often used to apply to both voluntary and spontaneous/automatic movements.11-13 The current bradykinesia definition in the context of diagnostic criteria for PD includes both slowness and progressive reduction in movement amplitude and velocity when performing repetitive movements, that is, decrement or sequence effect.3, 4, 10 The current concept of bradykinesia, including potentially distinct motor abnormalities, is reflected in the evaluation scales routinely used in clinical practice.14, 15 The current bradykinesia definition has some clinical and pathophysiological inconsistencies.10, 16, 17 In this paper, we first review the historical background of the definition of bradykinesia and related terms. We then summarize the various inconsistencies that undermine the current bradykinesia definition and its applicability in different conditions and propose redefining bradykinesia. We finally emphasize the usefulness of a new bradykinesia definition and discuss the potential implications of this proposal. The terminology of bradykinesia, hypokinesia, and akinesia has long been debated.8 Interestingly, none of these terms were first introduced with specific reference to parkinsonism. The term bradykinesia was introduced in 1907 to describe slowed voluntary movements in dystonia.18 About 20 years later, the so-called “bradykinetic syndrome” has been described in PD and other conditions to specifically refer to slowness at the beginning and during the execution of voluntary movements.19 The term hypokinesia was introduced in 187820 as opposite to hyperkinesia.8 In the context of PD, hypokinesia was used for the first time in the early 1900s, with reference to the lack of “associated, successive, reactive and expressive movements.”21 Later on, it was suggested that hypokinesia could be adopted only when an amplitude decrement was present.22 The term akinesia was introduced in the second half of the 19th century to describe decreased motion, including paralysis. Subsequently, the term akinesia has been mainly adopted in psychiatric patients,23 and it was used for the first time in PD only in 1870, to indicate the “paralysis” occurring in the advanced disease stages.24 In the early 1990s, Gibb and Lees defined bradykinesia as “slowness of voluntary movement with a progressive reduction in speed and amplitude of repetitive actions.”3, 25 Accordingly, the current diagnostic criterion for PD4 defines bradykinesia as “slowness of movement AND decrement in amplitude or speed (or progressive hesitations/halts) as movements are continued,” due to two main clinical assumptions: (1) these signs are generally present during the examination of a PD patient and (2) in parkinsonism caused by PD, a decline in either speed or amplitude or both is seen as repetitive movements are continued, a feature usually not observed in other parkinsonisms.4 The concept of bradykinesia is even more complicated in AP.10 The diagnostic criterion for progressive supranuclear palsy (PSP)5 indicates akinesia, not bradykinesia, as a core feature and used this term synonymously with parkinsonism. The criteria for multiple system atrophy (MSA)1 diagnosis require bradykinesia to be associated with rigidity and tremor, without specifying what features would qualify as bradykinesia. Finally, the criteria for corticobasal syndrome (CBS)2 use bradykinesia and akinesia interchangeably. Only the clinical criteria for dementia with Lewy bodies (DL","journal":"Movement Disorders","year":2023,"id":317154,"datarank":0.0,"base_score":0.0,"endowment":0.0,"self_citation_contribution":0.0,"citation_network_contribution":0.0,"self_endowment_contribution":0.0,"citer_contribution":0.0,"corpus_percentile":null,"corpus_rank":null,"citation_count":83,"citer_count":0,"citers_with_citation_signal":0,"citers_with_endowment":0,"datacite_reuse_total":0,"is_dataset":false,"is_dataset_confidence":0.9583,"is_data_producer":false,"deposit_databanks":null,"is_oa":true,"file_count":0,"downloads":0,"has_version_chain":false,"published_date":"2023-01-01","fair_score":null,"fair_percentile":null,"algorithm_id":"datarank_citation_only_1hop_v6","ranking_scope":"data_only","authors":[{"id":233015,"name":"Alberto J. Espay","orcid":"0000-0002-3389-136X","position":1,"is_corresponding":false},{"id":263851,"name":"Alfonso Fasano","orcid":"0000-0001-5346-0180","position":2,"is_corresponding":false},{"id":1022254,"name":"Giulia Paparella","orcid":"0000-0002-7760-9442","position":3,"is_corresponding":false},{"id":255823,"name":"Mark Hallett","orcid":"0000-0002-3180-6811","position":4,"is_corresponding":false},{"id":347471,"name":"Alfredo Berardelli","orcid":"0000-0003-3598-3142","position":5,"is_corresponding":false},{"id":566229,"name":"Matteo Bologna","orcid":"0000-0003-0165-0833","position":0,"is_corresponding":true}],"reference_count":59,"raw_metadata":null,"created_at":"2026-07-19T01:06:50.336418Z","pmid":"36847357","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":[]}