The brainstem lateral mesencephalon contains the pedunculopontine nucleus and cuneiform nuclei which regulate locomotion. These regions receive cortical input and influence movement via outputs to the basal ganglia, thalamus, and spinal cord. Drop attacks can occur without loss of consciousness due to conditions like transient ischemic attacks or vestibular dysfunction. A thorough history and exam is needed to determine the etiology of falls, which may be due to various neurological, cardiac, or orthopedic disorders.

1. FALLS AND DROP
ATTACKS

2. MESENCEPHALIC LOCOMOTOR
REGION
► The brainstem lateral mesencephalus is a highly conserved supraspinal
locomotor centre, includes the pedunculopontine (PPN) and cuneiform
nuclei
► The pedunculopontine and cuneiform nuclei receive direct cortical inputs,
and are well positioned to influence locomotor behaviour via ascending
outputs to the basal ganglia and thalamus, as well as via descending outputs
to the spinal cord

3. ► The pedunculopontine nucleus (PPN) is located in the mesopontine tegmentum
and is best delineated by a group of large cholinergic neurons adjacent to the
decussation of the superior cerebellar peduncle
► Cluster of large, darkly staining neurons adjacent to the decussation of the superior
cerebellar peduncle

4. FALLS
Most commonly associated with
chronic disorders like neuropathies,
stroke, multiple sclerosis,
parkinsonism and dementia.
DEFINITION: Inability to maintain an
upright posture during a postural
challenge

5. NEUROMUSCULAR
SYSTEM
SENSORY
SYSTEM
VESTIBULOCEREBELLAR
SYSTEM
COGNITIVE
SYSTEM

6. DROP ATTACKS
► DEFINITION : SUDDEN FALL OCCURRING WITHOUT A PRODROME THAT MAY
OR MAY NOT BE ASSOCIATED WITH LOSS OF CONSCIOUSNESS AND
CANNOT BE PREVENTED BY ASSISTED DEVICES

8. QUESTIONS TO ASK
► PAST HISTORY OF FALL
► CIRCUMSTANCES OF FALL
► LOSS OF CONSCIOUS
► PRECEDING SENSATION – LIGHT HEADEDNESS, VERTIGO OR PALPITATIONS
► PAST HISTORY OF SEIZURE DISORDER , STARTLE SENSITIVITY, EXCESSIVE
DAYTIME SLEEPINESS OR FALLS PRECIPITATED BY STRONG EMOTIONS
► HEADACHE OR MIGRAINE
► HISTORY OF TIAs OR PRESENCE OF VASCULAR RISK FACTORS
► SENSORY LOSS, LIMB WEAKNESS OR STIFFNESS
► VISUAL SYMPTOMS, HEARING LOSS, VERTIGO OR TINNITUS

9. DROP ATTACKS WITH LOSS OF
CONSCIOUSNESS

10. SYNCOPE

11. CARDIAC SYNCOPE
TACHYARRYTHMIAS
BRADYARRYTHMIAS
STRUCTURAL HEART DISEASE

12. STRUCTURAL
HEART
DISEASE
OUTFLOW
OBSTRUCTION
INFLOW
OBSTRUCTION
MECHANICAL
FAILURE

13. ORTHOSTATIC HYPOTENSION
► Clinically, this is diagnosed by a sustained reduction in systolic blood pressure of at
least 20 mmHg or diastolic blood pressure of 10 mmHg within three minutes of
standing after being supine for five minutes or at a 60-degree angle on the tilt table
► CLASSIC AND DELAYED
► NEUROGENIC AND NON NEUROGENIC / MEDICATION INDUCED

14. NEUROGENIC ORTHOSTATIC
HYPOTENSION
NEURODEGENERATIVE DISEASES
•PARKINSONISM
NEUROPATHIES

15. ► LONG QT SYNDROMES – MISDIAGNOSED AS EPILEPSY
► GLOSSOPHARYNGEAL NEURALGIA : PAINFUL SYNCOPE
► HYPERVENTILATION:
HYPERVENTILATION
CO2 WASHOUT
CEREBRAL VASOCONSTRICTION
SYNCOPE

17. SITUATIONAL SYNCOPE
► COUGH SYNCOPE
► MICTURITION SYNCOPE
► VALSAVA MANOUVERE
► DIVING
► SWALLOWING

18. SEIZURES
► EPILEPTIC DROP ATTACKS: multiple mechanisms like asymmetric tonic
contraction of limbs and axial muscles, loss of tone of postural muscles and
epilepsy related arrythmias.
► Pediatric epileptic encephalopathy syndromes like Lennox-Gastaut
syndrome and Dravet syndrome, as well as the myoclonic epilepsies
present as drop attacks.

19. ► Psychogenic pseudosyncope
► Psychiatrically, most cases are classified as conversion disorder, which is
hypothesized to represent the physical manifestation of internal stressors

20. DROP ATTACKS WITHOUT LOC
► TIA : falls from TIA usually occurs without warning or obvious explanation
like tripping
► Vascular distribution includes posterior circulation and anterior circulation

21. ► Vertebrobasilar insufficiency : rarely an isolated event.
► Usually associated with other symptoms like vertigo, diplopia, ataxia, motor
weakness and hemisensory loss.
► Usually associated with transient ischemia of corticospinal tracts and
paramedian reticular formation
► Sometimes an ominous precursor of progressive basilar artery thrombus.

22. ► Anterior circulation TIA: Drop attacks attributed to impaired perfusion of
the parasagittal premotor and motor cortex controlling the lower
extremities.
► Common root origin of both ACAs occurs in 20% population making them
prone to paraparesis from a single embolus.
► Rare causes : carotid dissection and frontal arteriovenous fistulas

23. Third ventricle and posterior fossa
abnormalities
► Drop attacks can be a manifestation of third ventricle cysts, chiari
malformation or mass lesions in posterior fossa.
► With colloid cysts of the third ventricle unprovoked falling is the second most
common symptom next to position induced headaches
► Pineal cysts- occasional cause
► Chiari malformation
► Posterior fossa arachnoid cysts

24. OTOLITH CRISIS
► VESTIBULAR DROP ATTACKS: 6% of Menieres disease- Tumarkin otolithic crisis
► Stimulation of otolith receptors in the saccule triggers inappropriate
postural reflex adjustments through vestibulospinal pathways causing falls
without vertigo

25. CATAPLEXY
► TETRAD OF NARCOLEPSY : cataplexy (loss of lower limb muscle tone),
excessive daytime sleepiness, hypnagogic hallucinations and sleep
paralysis.
► Preserved consciousness
► Attack less than a minute
► Provoked by strong emotion

26. FALLS
► NEUROMUSCULAR DISORDERS AND MYELOPATHY
► Proximal muscle weakness causing gait abnormalities, lumbosacral
radiculopathy, myelopathy, channelopathies and NMJ disorders

27. ► Stroke : weakness, ataxia, sensory
deafferentation, hemianopsia, diplopia, anosognosia, hemineglect,
vestibular tilting, and acquired gait abnormalities are obvious risk
enhancing factors.
► Post stroke depression and immobilisation

28. Other cerebral and cerebellar
disorders
► Asterixis : in metabolic encephalopathies – characteristic loss of postural tone
► Cerebellar diseases : truncal ataxia
► Episodic ataxia syndromes and familial hemiplegic migraine
► Hyperekplexia – increased startle sensitivity
► Normal pressure hydrocephalus

29. CRYPTOGENIC FALLS
► FALLS OF UNKNOWN ETIOLOGY
► Common in women over the age of 40
► No loss of consciousness/dizziness/ sense of imbalance

30. Aging and neurodegeneration
► Significant alterations in quantitative gait characteristics evolve with
advancing age, even in healthy individuals.
► In the future, standardized measurement of gait speed
could be included in the routine clinical assessment of the elderly,
akin to a “vital sign” because slow speed (≤0.6 m/sec) has strong
predictive power for all-cause mortality

31. ► Cognitive circuitry in the frontal lobe
and in the temporoparietal cortex is also involved
in gait and balance functions, explaining the link between declining
stability and cognition in the elderly, sometimes described as “brain
failure.”
Reduction of step length or stoppage when talking (“stops walking while talking”)
is a reliable indicator of an increased fall risk in the elderly

32. BASAL GANGLIA DISORDERS
► Nearly all patients with Parkinson disease (PD) fall over the course of their
illness and suffer twice as many fractures as age-matched controls.
► Disease duration, depression, cognitive impairment,
treatment-related motor fluctuation, sedating drug use, coexisting rapid
eye movement (REM) sleep behavior disorder (RBD) and, especially,
cardiovascular autonomic dysfunction with orthostatic hypotension.
► DOPAMINE INDUCED MOTOR FLUCTUATIONS – PEAK DOSE DYSKINESIAS
AND OFF PERIODS

33. ► Freezing of gait (FOG), another fall-promoting feature of PD, associated
with changes in the mesencephalic locomotor and balance centers (PPN
and locus coeruleus)
► Degeneration of the cholinergic PPN appears to be a key factor for
impaired postural control in PD.

34. PROGRESSIVE SUPRANUCLEAR PALSY
AND OTHER PARKINSONIAN
SYNDROMES
► PSP : PARKINSONIAN FEATURES, AXIAL RIGIDITY, SPASTICITY AND
OPHTHALMOPARESIS.
► More likely in the backward direction than in those with PD, even with
equivalent functional impairment.
► RBD is a precursor of PSP and an underrecognized cause of nocturnal falls.

35. ► Clinical evaluation – fall mechanism + predisposing medical conditions +
correctable risk factors
► In the absence of an overt explanation for falls, a syncopal event for
which the patient may be amnestic becomes more likely