Frontal lobe syndromes

Dr Saradhi, svs medical college, ap psychiatry

1. Frontal Lobe Disorder Moderator: Dr. Saradhi

2. Outline Introduction Functional anatomy of the frontal lobes Neurotransmitters in the frontal lobes Frontotemporal Dementia Frontal lobe syndrome Frontal lobe epilepsy Schizophrenia & Frontal lobe Depression & frontal lobe Testing prefrontal cortical function Common causes of frontal lobe syndromes

3. … one hundred trillion synapses in a single human brain organized into exquisitely complex circuits… responding to experience, drugs, disease, and injury… Complexity of the Brain

4. Complexity of the Brain As befits the 3-pound organ of the mind, the human brain is the most complex structure ever investigated by our science.

5. It is useful to think of the brain as containing six or seven component parts. The largest and most advanced part consists of the left and right cerebral hemispheres, which appear to be more or less symmetrical. They are covered with a layer of gray matter called the cerebral cortex. Each of the cerebral hemispheres has traditionally been divided into four "lobes," which are named after the bones of the skull that surround them: frontal, parietal, occipital, and temporal.

6. The frontal lobe is the largest and least understood, beginning at the front of the brain and reaching back to the central sulcus & laterely lateral sulcus. The area between the central and precentral sulci helps control body movements and is called the "motor area," while the remainder of the frontal lobe probably modulates various aspects of thinking, feeling, imagining, and making decisions.

7. Functional Frontal Lobe Anatomy Largest of all lobes SA: ~ 1/3 of each hemisphere 3 major areas in each lobe Dorsolateral aspect Medial aspect Inferior orbital aspect

8. Functional Frontal Lobe Anatomy Lateral sulcus/ Sylvian fissure Central sulcus Motor speech area of Broca Frontal eye field B 44, 45 B 9, 10, 11, 12 B 8 Primary motor area Premotor area Prefrontal area B6 B4 Supplementary motor area (medially)

9. Functional Frontal Lobe Anatomy Motor cortex Primary Premotor Supplementary Frontal eye field Broca’s speech area Prefrontal cortex Dorsolateral Medial Orbitofrontal

10. Motor Cortex Primary motor cortex Input: thalamus, BG, sensory, premotor Output: motor fibers to brainstem and spinal cord Function: executes design into movement Lesions: / tone;  power;  fine motor function on contra lateral side

11. Motor Cortex Premotor cortex Input: thalamus, BG, sensory cortex Output: primary motor cortex Function: stores motor programs; controls coarse postural movements Lesions: moderate weakness in proximal muscles on contralateral side

12. Motor Cortex Supplementary motor Input: cingulate gyrus , thalamus, sensory & prefrontal cortex Output: premotor , primary motor Function: intentional preparation for movement; procedural memory Lesions: mutism , akinesis ; speech is non-spontaneous

13. Motor Cortex Frontal eye fields Input: parietal / temporal (what is target); posterior / parietal cortex (where is target) Output: caudate; superior colliculus; paramedian pontine reticular formation Function: executive: selects target and commands movement (saccades) Lesion: eyes deviate ipsilaterally with destructive lesion and contralaterally with irritating lesions

14. Motor Cortex Broca’s speech area Input: Wernicke’s Output: primary motor cortex Function: speech production (dominant hemisphere); emotional, melodic component of speech (non-dominant) Lesions: motor aphasia; monotone speech

15. Prefrontal Cortex Orbital prefrontal cortex Connections: temporal,parietal, thalamus, GP, caudate, SN, insula, amygdala Part of limbic system Function: emotional imput, arousal, suppression of distracting signals Lesions: emotional lability, disinhibition, distractibility, ‘hyperkinesis’

16. Prefrontal Cortex Dorsomedial prefrontal cortex Connections: temporal,parietal, thalamus, caudate, GP, substantia nigra, cingulate Functions: motivation, initiation of activity Lesions: apathy; decreased drive/ awareness/ spontaneous movements; akinetic-abulic syndrome & mutism

17. Prefrontal Cortex Dorsolateral prefrontal cortex Connections: motor / sensory convergence areas, thalamus, GP, caudate, SN Functions: monitors and adjusts behavior using ‘working memory’ Lesions: executive function deficit; disinterest / emotional reactivity;  attention to relevant stimuli

18. Neurotransmitters Dopaminergic tracts Origin: ventral tegmental area in midbrain Projections: prefrontal cortex (mesocortical tract) and to limbic system (mesolimbic tract) Function: reward; motivation; spontaneity; arousal

19. Neurotransmitters Norepinephrine tracts Origin: locus ceruleus in brainstem and lateral brainstem tegmentum Projections: anterior cortex Functions: alertness, arousal, cognitive processing of somatosensory info

20. Neurotransmitters Serotonin tracts Origin: raphe nuclei in brainstem Projections: number of forebrain structures Function: minor role in prefrontal cortex; sleep, mood, anxiety, feeding

21. Functional Frontal Lobe Anatomy Five ‘frontal subcortical circuits’ (Cummings,‘93) Motor Oculomotor Dorsolateral prefrontal Lateral orbitofrontal Anterior cingulate

22. Functional Frontal Lobe Anatomy ‘Frontal subcortical circuits’ Thalamus Frontal cortex Striatum Caudate & Putamen Globus Pallidus & Substantia Nigra

23. Frontal subcortical Circuits: 1. Motor Circuit Supplementary Motor & Premotor: planning, initiation & storage of motor programs; fine-tuning of movements Motor:final station for execution of the the movement according to the design SMA, Premotor,Motor Putamen Globus Pallidus Thalamus Hypo-thalamus

24. Frontal subcortical Circuits: 2. Oculomotor Circuit Voluntary scanning eye movement Independent of visual stimuli Frontal Eye Field Central Caudate Globus Pallidus Substantia Nigra Thalamus

25. Frontal subcortical Circuits: 3. Dorsolateral Prefrontal Circuit Executive functions: motor planning, deciding which stimuli to attend to, shifting cognitive sets Attention span and working memory Lateral Prefrontal Caudate Globus Pallidus Substantia Nigra Thalamus

26. Frontal subcortical Circuits: 4. Lateral Orbitofrontal Circuit Emotional life and personality structure Arousal, motivation, affect Orbitofrontal cortex: consciousness Caudate Globus Pallidus Substantia Nigra Thalamus Infero-lateral prefrontal Orbito-frontal

27. Frontal subcortical Circuits: 5. Anterior Cingulate Circuit Abulia, akinetic mutism Anterior Cingulate Gyrus Ventral Striatum Globus Pallidus Substantia Nigra Thalamus

28. Frontal Lobe Syndromes The Case of Phineas Gage tamping iron blown through skull: L frontal brain injury excellent physical recovery dramatic personality change: stubborn , lacked in consideration for others, had profane speech, failed to execute his plans

29. Frontotemporal Lobe Dementia Frontotemporal lobar degeneration (FTLD) is a neurodegenerative disease that selectively attacks the frontal and anterior temporal regions . FTLD occurs in 5–15% of patients with dementia and it is the third most common degenerative dementia , following only Alzheimer’s disease (AD) and dementia with Lewy bodies. Typical age of onset is between 50 and 60 years, although FTLD can occur as early as the 20s and has been reported in the ninth decade.

30. Frontotemporal Lobe Dementia In contrast to AD, in which memory loss is usually the first symptom, the initial symptoms of FTLD often involve changes in personality , behavior, affective symptoms, and language function. Most patients with FTLD begin with language (left-sided cases) or emotional ( right-sided cases ) changes. The lack of insight seen in FTLD,leads patients to ignore or deny their deficits. The core features of FTLD as defined by the Neary criteria ( Neary et al., 1998) are early decline in social and personal conduct, emotional blunting , and loss of insight.

31. Frontotemporal Lobe Dementia The clinical onset is insidious, with a slow gradual progression. Although the neuropsychiatric profile for patients with FTLD varies. Behavior problems such as overeating, repetitive compulsive behaviors , apathy, and agitation and disinhibition , develop in the majority of these patients as the disease progresses. T he estimated duration of the illness is around 6–10 years. SSRI improved a variety of psychiatric symptoms, including irritability, depression , repetitive behaviors, and hyperorality .

32. Frontal Lobe Syndromes The dorsolateral frontal cortex is concerned with planning, strategy formation, and executive function. Patients with dorsolateral frontal lesions tend to have apathy, personality changes, abulia , and lack of ability to plan or to sequence. patients have poor working memory for verbal information (if the left hemisphere is predominantly affected) or spatial information ( if right hemisphere lesion). The frontal operculum contains the center for expression of language. Patients with left frontal operculum lesions may demonstrate  Broca aphasia and defective verb retrieval, whereas patients with exclusively right opercular lesions tend to develop expressive aprosodia .

33. The orbitofrontal cortex is concerned with response inhibition. Patients with orbitofrontal lesions shows disinhibition , emotional lability , and memory disorders. Personality changes from orbital damage include impulsiveness, a jocular attitude, sexual disinhibition , and complete lack of concern for others. Patients with superior mesial lesions typically develop akinetic mutism . Patients with inferior mesial (basal forebrain) lesions tend to manifest anterograde and retrograde amnesia and confabulation. 

34. Causes Mental retardation Traumatic brain injury Brain tumors Degenerative dementias including Alzheimer disease, dementia with Lewy bodies,  Parkinsonian dementias, and  frontotemporal dementias Cerebrovascular disease Schizophrenia major depression  multiple sclerosis It is associated with blood alcohol level and occurs during acute intoxication with many recreational drugs.

35. Clinical picture Profound change in personality. Lack of initiation and spontanity . Response are sluggish. Occasionally patient are hyperactive and restless. Mood is often euphoric and out of keeping with patients situation. Irritability and outbursts are common. Loss of finer senses. Judgements are impaired. Fail to plan and carry through ideas.

36. Frontal Lobe Epilepsy Frontal lobe epilepsy is characterized by recurrent seizures arising from the frontal lobes. Seizures may arise from any of the frontal lobe areas, including orbitofrontal,dorsolateral , opercular , supplementary motor area, motor cortex, or cingulate gyrus . In most centers frontal lobe epilepsy accounts for 20-30% of operative procedures involving intractable epilepsy. No significant gender-based frequency. In a large series of cases, mean subject age was 28.5 years with age of epilepsy onset 9.3 years for left frontal epilepsy and 11.1 years for right frontal epilepsy.

37. Clinical Picture Patients with frontal lobe seizures may present with a clear epileptic syndrome or with unusual behavioral or motor manifestations that are not immediately recognizable as seizures. may be associated with facial grimacing, vocalization, or speech arrest. seizures frequently preceded by a somatosensory aura. Complex behavioral events characterized by motor agitation and gestural automatisms; viscerosensory symptoms and strong emotional feelings often described; motor activity and may involve pelvic thrusting, pedaling, or thrashing, often accompanied by vocalizations or laughter/crying; seizures often bizarre and may be diagnosed incorrectly as psychogenic

38. Differential Diagnoses Absence Seizures Periodic Limb Movement Disorder Psychogenic Nonepileptic Seizures REM Sleep Behavior Disorder Somnambulism (Sleep Walking) Temporal Lobe Epilepsy

39. Expressive aphasia Expressive aphasia, known as  Broca's aphasia caused by damage or developmental issues in anterior regions of the brain, including the left posterior inferior frontal gyrus  known as  Broca's area ( Brodmann area 44and  Brodmann area 45). Sufferers of this form of aphasia exhibit the common problem of  agrammatism . For them, speech is difficult to initiate, non-fluent, labored, and halting. Similarly, writing is difficult as well. Intonation and stress patterns are deficient. Language is reduced to disjointed words and sentence construction is poor. comprehensionis generally preserved, meaning interpretation dependent on syntax and phrase structure is substantially impaired.  Patients who recover go on to say that they knew what they wanted to say but could not express themselves. Residual deficits will often be seen.

40. Schizophrenia & frontal lobe some schizophrenic symptoms are found in frontal lobe disorder, in particular that involving dorsolateral prefrontal cortex. Symptoms included are those of the affective changes, impaired motivation, poor insight. Evidence for frontal lobe dysfunction in schizophrenic patients has been noted in neuropathologic studies like EEG studies, in CT scan, with MRI, and in cerebral blood flow studies. H ypofrontality is documented in several studies using PET. These findings emphasize the importance of neurologic and neuropsychologic investigation of patients with schizophrenia.

41. Depression & Frontal lobe  it has been found that the right frontal lobe demonstrated increased activity in response to negative moods whereas left frontal activity decreases. repetitive transcranial magnetic stimulation of the right frontal lobe reduces depressive symptoms , whereas left frontal activity increase depression as demonstrated through functional imaging studies. Not only reductions in left frontal activity, but injuries to the left frontal lobe have been consistently associated with depression, "psycho-motor" retardation, apathy, irritability, and blunted mental functioning.  psychiatric patients classified as depressed demonstrate insufficient left frontal activation and arousal. In severely depressed patients demonstrate insufficient activation and a significant lower integrated amplitude of the EEG evoked response over the left vs right frontal lobe.

42. Wisconsin Card Sorting Test abstract thinking and set shifting; L>R Trail Making visuo -motor track, conceptualization, set shift Stroop Color & Word Test attention, shift sets; L>R Tower of London Test planning Testing for Frontal lobe function

43. Wisconsin Card Sorting Test “Please sort the 60 cards under the 4 samples. I won’t tell you the rule, but I will announce every mistake. The rule will change after 10 correct placements.”

44. Trail Making Test A C 1 2 7 3 D 5 B 4 6 Various levels of difficulty: 1. “Please connect the letters in alphabetical order as fast as you can.” 2. “Repeat, as in ‘1’ but alternate with numbers in increasing order”

45. Stroop Color and Word Tests RED BLUE ORANGE YELLOW GREEN RED PURPLE RED GREEN YELLOW BLUE RED YELLOW ORANGE RED GREEN BLUE GREEN PURPLE RED “Please read this as fast as you can”

46. Tower of London Tests Various levels of difficulty: e.g. “Please rearrange the balls on the pegs, so that each peg has one ball only. Use as few movements as possible”

47. Diseases Commonly Associated With Frontal Lobe Lesions Traumatic brain injury Gunshot wound Closed head injury Widespread stretching and shearing of fibers throughout Frontal lobe more vulnerable Contusions and intracerebral hematomas

48. Diseases Commonly Associated with Frontal Lobe Lesions Frontal Lobe seizures Usually secondary to trauma Difficult to diagnose: can be odd (laughter, crying, verbal automatism, complex gestures)

49. Diseases Commonly Associated With Frontal Lobe Lesions Vascular disease Common cause especially in elderly ACA territory infarction Damage to medial frontal area MCA territory Dorsolateral frontal lobe Anterior Communicating artery aneurysm rupture Personality change, emotional disturbance

50. Diseases Commonly Associated With Frontal Lobe Lesions Tumors Gliomas, meningiomas subfrontal and olfactory groove meningiomas: profound personality changes and dementia Multiple Sclerosis Frontal lobes 2 nd highest number of plaques euphoric/depressed mood, Memory problems, cognitive and behavioral effects

51. Diseases Commonly Associated With Frontal Lobe Lesions Degenerative diseases Pick’s disease Huntington’s disease Infectious diseases Neurosyphilis Herpes simplex encephalitis

52. Diseases Commonly Associated with Frontal Lobe Lesions Psychiatric Illness – proposed associations Depression Schizophrenia OCD PTSD ADHD

53. Thanks for your patience